Self-Injurious Behaviour during Early Childhood in a General Population Sample – Exploratory Analysis in the Norwegian Mother, Father and Child Cohort Study (MoBa)

Self-Injurious Behaviour during Early Childhood in a General Population Sample – Exploratory Analysis in the Norwegian Mother, Father and Child Cohort Study (MoBa) | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Self-Injurious Behaviour during Early Childhood in a General Population Sample – Exploratory Analysis in the Norwegian Mother, Father and Child Cohort Study (MoBa) Anastasia Izotova, Line Indrevoll Stänicke, Becky Mars, Kim Stene-Larsen, and 7 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7235784/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Objective Self-harm is one of the strongest risk factors for suicide and a major public health concern. Most existing research has focused on adolescents and adults. Knowledge about the prevalence and correlates of self-harm in children is limited. Method Lived experience interviews informed the analysis plan. In the Norwegian Mother, Father and Child Cohort Study (MoBa), mothers reported on self-injurious behaviour (SIB) at age 3 and 8 years (N=35,494): ‘Does your child ever injure himself/herself deliberately, such as by biting his/her arm or banging his/her head?’. We examined the prevalence of SIB and the prevalence patterns of sociodemographic, neurodevelopmental and mental health factors. Results Mothers answered ‘yes’ on the SIB item at age 3 only (‘ transient ’) for 6.6% ( n =2,336) of the children, 1.2% ( n =434) at 8 years only (‘ emergent ’), and 0.5% ( n =181) at both 3 and 8 years (‘ persistent ’). We observed different patterns of sociodemographic, mental health, and neurodevelopmental factors for all SIB groups compared to No SIB , with individuals in the Emergent and Persistent SIB groups often most distinct from those reporting no SIB. Several factors also distinguished these two groups - most notably rates of paternal depression diagnoses and reports of children's motor developmental delay and sleep problems. Conclusion Groups reporting SIB in childhood had a higher prevalence of mental health and neurodevelopmental conditions. This pattern differed depending on when SIB first emerged and whether it persisted. Future studies should investigate the potential underlying mechanisms for the reported prevalence patterns and their implications for SIB prevention in children. MoBa MBRN childhood self-harm self-injury longitudinal mental health Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Globally, suicide is the cause of death for more than 700,000 people every year and is the 4th most common cause of death among adolescents and young adults from ages 15 to 29 years[ 1 ]. Therefore, the focus on suicide prevention is an important priority for global health, and early prevention is crucial to decrease the number of suicide deaths. Self-harm was shown to be a strong predictor of the transition from suicidal thoughts to suicide attempts[ 2 ] and suicide [ 3 ], [ 4 ]. Early self-harm prevention, recognition and treatment may therefore be important factors in reducing suicide rates as well as the development of other mental health conditions. The estimated lifetime prevalence of self-harm in adolescents varies greatly across different countries, study designs and samples, from around 4.3% up to 47.1%[ 5 ]. The differences also depend on the definition and measurement of self-harm used across studies, geographic regions and research fields. Some definitions, such as the National Institute for Health and Care Excellence (NICE) guidelines in the UK[ 6 ], describe behaviours such as self-injury or self-poisoning as self-harm irrespective of the apparent purpose, whereas others make a distinction between self-harm that occurs with and without suicidal intent. Several studies suggest an increasing prevalence of self-harm, particularly among children and adolescents[ 7 ], [ 8 ], [ 9 ]. Tørmoen et al.[ 10 ] reported an increase in self-reported self-harm prevalence in the last 12 months from 4.1% in 2002 to 16.2% in 2018 among Norwegian 13-15-year-old adolescents. Little is known about the prevalence of self-harm behaviour among children below the age of 12 in general population samples. Previous research, predominantly focusing on adolescents and adults, has shown associations of self-harm with various psychosocial and sociodemographic factors such as depression, anxiety, peer-related victimisation, sex, family environment or educational attainment[ 11 ]. Studies on which factors are associated with self-harm in younger children remain limited. Better characterization of self-harm in younger children is necessary for more effective prevention, identification and treatment. In this study, we use the term ‘self-injurious behaviour’ (SIB), as this best reflects the behaviours captured by the questionnaire item available ‘Does your child ever injure himself/herself deliberately, such as by biting his/her arm or banging his/her head?’ - and data on the intention behind the act(s) was not available. We examined the occurrence of SIB at ages 3 and 8, including whether it was ‘ transient ’ (only at age 3), ‘ emergent ’ (only at age 8) or ‘ persistent ’ (at both 3 and 8) across age. We also described the patterns of sociodemographic, neurodevelopmental and mental health factors for these SIB groups in early childhood. Methods Study Cohort MoBa is a population-based pregnancy cohort study conducted by the Norwegian Institute of Public Health. Participants were recruited from all over Norway from 1999–2008[ 12 ]. The women consented to participation in 41% of the pregnancies. The cohort includes approximately 114,500 children, 95,200 mothers and 75,200 fathers. The establishment of MoBa and initial data collection was based on a license from the Norwegian Data Protection Agency and approval from The Regional Committees for Medical and Health Research Ethics. The MoBa cohort is currently regulated by the Norwegian Health Registry Act. The current study was approved by The Regional Committees for Medical and Health Research Ethics (REK project number: 2016/1702). Questionnaires were self-reported by mothers at baseline (15–20 weeks of pregnancy), 3 years and 8 years, and by the fathers at baseline. Registry data was used from the Norwegian Patient Registry (NPR) and the Medical Birth Registry of Norway (MBRN). MBRN is a national health registry containing information about all births in Norway. NPR includes diagnoses received between 2008–2021 in specialized healthcare services in hospitals, private and public outpatient clinics. Data from the Autism Birth Cohort (ABC) study was used to validate the SIB measure at 3 years. For the ABC study, parents participating in MoBa were invited for an in-person assessment of their children (n = 1,306 invitations) based on specific criteria related to autistic traits, an autism diagnosis or having a sibling with an autism diagnosis as well as 915 children who were randomly selected as controls, with an overall participation rate of around 50%[ 13 ]. Lived Experience Interviews We conducted four lived experience interviews to inform the analysis plan. The interview questions were developed by the first author, followed by an in-depth team discussion and collective decision on their final form. The questions formed the interview guidelines which were accompanied by a debriefing section and a tailored consent form. Adults with lived experience of self-harm in childhood (4–9 years) were recruited through social media and personal referrals. The participants provided written informed consent and received a gift card equalling 500 NOK as compensation for their time. Participants were asked about their thoughts and priorities for research on self-harm, including which risk and protective factors they considered important. The responses formed the decisions on variable inclusion in the analysis. There was a diversity of ethnic background and neurodiversity among the participants. However, all participants identified as female. Measures Abbreviations used are explained in the supplementary materials (S1). All included measures are described in detail in S2 and summarised below. Self-injurious behaviour SIB of the children was reported by the mothers using one item of the Social Communication Questionnaire (SCQ)[ 14 ] at the ages of 3 and 8 years. The item ‘Does your child ever injure himself/herself deliberately, such as by biting his/her arm or banging his/her head?’ was answered by the mothers with ‘yes’ or ‘no’. SIB item validation An interview question on SIB from the Autism Diagnostic Interview Revised (ADI-R) as part of the Autism Birth Cohort (ABC) study clinical assessment was used to validate the reported SIB in the questionnaire at 3 years. The responses to the ADI-R interview item were restricted to a maximum of one year after the 3-year questionnaire in MoBa was filled out by the mothers. Sociodemographic measures Sociodemographic measures included at baseline for both mothers and fathers were: age at child’s birth, child’s registered sex at birth, employment status, level of education (whether they achieved college or university degree) and whether Norwegian is the native language of the child’s parents or grandparents. The maternal living situation at baseline (whether or not they are living with their partner), civil status (mothers being married or in a cohabitant status with their partners) reported in the 3-years-questionnaire, and a variable on whether the mothers were living with the child’s father in the 8-years-questionnaire were also included, allowing for comparisons across groups on factors regarding the maternal living situation and civil status at the different ages of their child. Health-related behaviours in mothers and fathers Health-related behaviour measures included at baseline are alcohol consumption and smoking from both parents. Furthermore, measures of eating behaviours in mothers from the 3-years-questionnaire were included, featuring items on behaviours to control weight such as fasting, use of laxatives, vomiting and hard physical exercise as well as an item on binge eating. Mental health and neurodevelopmental conditions in mothers, fathers and children Diagnostic groups were defined from registry data as having received an ICD-10 diagnostic code at least once for depression (F32, F33), anxiety disorders (F40, F41, F93), post-traumatic stress disorder (PTSD) (F43.1), bipolar disorder (BP) (F31), schizophrenia (F20), attention deficit hyperactivity disorder (ADHD) (F90), autism (F84.0, F84.1, F84.5, F84.8, F84.9) and eating disorders (F50). Adverse life experiences in mothers and children We included variables from the 8-year questionnaire on the child’s experiences with bullying, being bullied and being subject to physical violence by other children. For the mothers, a variable on experience with sexual abuse was included from the baseline questionnaire. Developmental characteristics in children Measures about the experience of developmental conditions or challenges included from the 3-years-questionnaire items on ‘delayed motor development’, ‘hyperactivity’, ‘abnormal speech development’, ‘sleep problems’, and ‘trouble relating to others’. Items included from the 8-years-questionnaire were ‘delayed psychomotor development’, ‘abnormal language development’, ‘hyperactivity’, ‘concentration or attention difficulties’, ‘autistic traits/autism/Asperger’s syndrome’, ‘behavioural problems (difficult and unruly)’ and ‘emotional difficulties (sad or anxious)’. Statistical Analysis Analyses were performed in R version 4.1.2[ 15 ]. Diagnostic data and MoBa questionnaire variables were extracted and pre-processed using the phenotools (v0.3.3) package[ 16 ]. A detailed description of variable cleaning steps is given in S2. We included MoBa children with childbirth registered in MBRN whose mothers responded to the SIB item when the child was 3 and 8 years old. First, we estimated the prevalence of SIB in the MoBa cohort at child’s ages of 3 and 8 years. We analysed the responses and reported the prevalence and persistence of SIB, forming four mutually exclusive groups: No SIB ( answered with ‘no’ at 3 and 8 years ) , Transient SIB ( answered with ‘yes’ at 3 years only ) , Emergent SIB ( answered with ‘yes’ at 8 years only ) and Persistent SIB ( answered with ‘yes’ at 3 and 8 years). Next, we described the sociodemographic, mental health and neurodevelopmental factors across each of the four groups using percentages with confidence intervals for binary variables and means with 95% confidence intervals for the continuous variables. This was an exploratory analysis, and the results are primarily descriptive. We examined the general pattern of results to describe the characteristics of the groups including those children who self-injured at different ages. We used independent sample chi square tests to compare prevalence of the characteristics in each of the self-injury groups to the No SIB group. Our results aim to generate hypotheses that can be tested in future analyses. To explore the potential impact of missing data, we conducted a sensitivity analysis comparing responders with non-responders at the child ages of 3 and 8 years for the following key demographic variables: mother living with a partner (at baseline), maternal employment status (at baseline), maternal highest educational attainment (at baseline), and only for 8 years, SIB reported at 3 years. Furthermore, we compared the diagnoses of mental health and neurodevelopmental conditions of the mothers and the children from NPR. Additionally, we examined the prevalence of SIB in absolute numbers and percentages per birth year to explore potential time effects. Results Prevalence and persistence of SIB Mothers responded for a total of 35,494 children in MoBa to the SIB item at both time points (3 and 8 years). As per the maternal report, 91.7% ( n =32,543) of the children did not show SIB at any of the assessed time points. The prevalence of Transient SIB (age 3 only) was 6.6% ( n =2,336), Emergent SIB (age 8 only) was 1.2% ( n =434) and Persistent SIB (both time points) was 0.5% ( n =181). Proportions of examined variables A detailed overview of all the proportions of the examined variables (sociodemographic variables, health-related behaviours in parents, mental health and neurodevelopmental conditions in mothers, fathers and children, measures of adverse life experiences in mothers and children, and mother-reported developmental conditions in the 3- and 8-year-old children) across each of the four groups is reported in the S3. Sociodemographic characteristics The mean age at child’s birth was significantly lower for both parents in all of the SIB groups in comparison to the No SIB group. The lowest mean age was in the Persistent SIB group. The parental mean age (SD) across all groups can be found in the S4. Binary sociodemographic variables of the parents as well as the child’s sex are reported in Figure 1. The same pattern of results was found across most of the sociodemographic variables, except for child sex, where the highest proportion of male children was observed for the Emergent SIB group. The proportion of living with a partner at baseline (mother), being married/cohabiting at the child’s age of 3 years (mother), parents living together at the child’s age of 8 years, holding a university degree (mother and father), being employed (mother and father), and Norwegian being the native language of the parents and grandparents was highest in the No SIB group, and lowest in the Persistent SIB group. Paternal university degree was not significantly different for Transient SIB in comparison to the No SIB group. Health-related behaviours in the parents Health-related behaviours of the parents across the SIB groups are reported in Figure 2. Maternal smoking during pregnancy was more frequent in the SIB groups (9% for Transient SIB , 10.6% for Emergent SIB , and 11.4% for Persistent SIB ) compared to the No SIB (5.5%) group. The self-reported proportion of smoking among fathers during their partner’s pregnancy was between 35.7% ( Persistent SIB ) and 43.9% ( Emergent SIB ). Mothers reported in the 3-years-questionnaire on behaviours aimed to control weight that they experienced in the last 18 months. The highest proportions were reported for the items on binge-eating behaviour (26.1% Persistent SIB ) and using hard exercise to control weight (17% Emergent SIB ). The differences in alcohol consumption were not significant for both parents across all SIB groups compared to the No SIB group. Maternal report of hard exercise did not differ significantly for the Persistent SIB from the No SIB group as well as the proportion of those who reported to use vomiting to control weight was not significantly different in the Emergent SIB compared the No SIB group. Mental health and neurodevelopmental conditions in mothers, fathers, and children Mental health and neurodevelopmental conditions in parents and children across the SIB groups are reported in Figure 3. Across maternal diagnoses registered in NPR – Figure 3 - panel A, the proportion was highest for the Emergent SIB and Persistent SIB groups. The most prevalent condition in the mothers was depression (14.8% Emergent SIB) , followed by anxiety disorder (10.8% Emergent SIB) and PTSD (5% Persistent SIB). Eating disorders did not differ significantly in the Transient SIB group from the No SIB group . For the fathers – Figure 3 - panel B, the overall rates of registered diagnoses were low, so not all percentages could be reported. Depression had the highest prevalence (7% Emergent and 8.5% Persistent SIB ), followed by anxiety (5.9% Emergent SIB ) and ADHD (5.6% Persiste nt SIB ). In children, Figure 3 – panel C, ADHD was the most prevalent condition (21.2% Emergent SIB , 19.3% Persistent SIB ), followed by anxiety (9.9%) and autism (9.4%) in the Persistent SIB group. Across child diagnoses, prevalences were highest for the Emergent and Persistent SIB groups, with rates of diagnoses in the Transient SIB group looking more similar to the No SIB group. Depression and eating disorders did not differ significantly between the Emergent and the No SIB group. Measures for adverse life experiences in mothers and children Adverse life experiences in mothers and children are shown in Figure 4. The proportion of 8-year-olds who were bullied by other children was three times higher in the Emergent SIB (21.3%) and Persistent SIB (21.8%) groups compared to No SIB (6.8%). The proportion of those who bullied others was also highest in the Emergent SIB (7.4%) and Persistent SIB (11%) groups. Reported experienced violence by other children showed an overall similar pattern to the ‘bullying other children’ item. Maternal experience of sexual abuse was reported by 16.4% of the mothers in the No SIB group. The proportion increased by about one-third in the Transient SIB group and nearly doubled in the groups Emergent SIB (31.6%) and Persistent SIB (32%). The differences were significant across all variables and for all SIB groups compared to the No SIB group in this category. Mother reported developmental conditions in the 3- and 8-year-old children Conditions related to the child’s development at the ages of 3 and 8 years and reported by the mothers are shown in Figure 5, panels A and B. As reported in the 3-year questionnaire, ‘Sleep problems’ were about 3.5 times more frequent in the Persistent SIB (14%) than in the No SIB (4.1%) group. Similarly, ‘abnormal speech development’ had the lowest proportion in the No SIB (3.3%) group and increased about 3.75 times in the Persistent SIB (12.5%) group. The proportion of ‘delayed motor development’ was almost six times higher in the Persistent SIB (11.9%) than in the No SIB (2%) group. While the proportion of ‘trouble relating to others’ is very low in the No SIB (0.2%) group and overall not very high in the other groups, it is 26 times higher in the Persistent SIB (4.5%) group. Also, the proportion of ‘hyperactivity’ is 15 times higher in the Persistent SIB (4.5%) compared to the No SIB (0.3%) group. All the reported items on developmental conditions in the 8-years-questionnaire show similarities in the proportion patterns - with the No SIB group showing the lowest proportion, the Transient SIB group showing a moderately increased proportion and the Emergent SIB as well as Persistent SIB groups showing the highest proportion. For instance, ‘Concentration or attention difficulties’ were reported for 7.3% of the children in the No SIB group, almost doubling the proportion for the Transient SIB (14.6%) group and being more than 4.5 times higher in the Emergent SIB (33.1%) and Persistent SIB (35%) groups. The proportion for the ‘concentration or attention difficulties’ item is also the highest reported proportion in this category, closely followed by ‘behavioural problems’ (34.5% in the Persistent SIB group) and ‘emotional difficulties’ (32.8% in the Persistent SIB group). Prevalences for all the reported variables at the ages of 3 and 8 years differ significantly across all SIB groups compared to the No SIB group. Sensitivity analysis SIB item responders have been compared to non-responders for the 3-year- and 8-year-questionnaire across selected sociodemographic variables as well as mental health and neurodevelopmental conditions (S5). Mothers who were non-responders were less likely to live with a partner, be employed and hold a university degree. Furthermore, non-responding mothers were more likely to be diagnosed with the majority of the selected mental health and neurodevelopmental conditions. Children with a missing response to the SIB item at the age of 8 years were more likely to receive a diagnosis of any of the included conditions, while non-responders at the age of 3 did not significantly differ from responders for diagnoses of autism, eating disorder or schizophrenia. Additionally, the prevalence of SIB was analysed per birth year – showing a small, but inconsistent increase from the early to the latest inclusion years in MoBa (S6). Self-injurious behaviour at three years – item validation To test the validity of the SCQ item assessing SIB at the age of three, we cross-validated the available data with responses to the ADI-R interview item on SIB that were available through the ABC study. The participants in the ABC study are a sub-sample from the MoBa sample. We ran specificity and sensitivity analyses which show a high specificity and positive likelihood ratios on the one hand, and low sensitivity and negative likelihood ratios on the other hand (S7). The high specificity shows that the SCQ item is a useful measure of the presence of SIB. However, the low sensitivity indicates that it is not as good at capturing the absence of SIB. One of the possible explanations can be that we restricted the ABC study measurement to maximum one year past the MoBa data collection of the 3-year questionnaire and that the SIB measured in the ABC study may have occurred after the MoBa questionnaire was filled out. Discussion In the present study, we investigated the prevalence and persistence of childhood SIB in the MoBa cohort and described the sociodemographic as well as mental health and neurodevelopmental characteristics of children who did self-injure compared to those who did not. The prevalence of SIB among children in the MoBa cohort reported at either 3 years only, 8 years only or both ages was 8.3%. The majority of characteristics showed a consistent pattern of results, with SIB groups tending to show a higher prevalence of low socioeconomic status, higher rates of mental health and neurodevelopmental diagnoses, and more developmental difficulties than the No SIB group. Among sociodemographic characteristics, the proportion of parents living with partners, being employed, holding a university degree as well as having Norwegian as their or their parents’ native language was slightly lower in the SIB groups compared to no SIB. The majority of children with reported SIB were male which is in line with previous findings in a recent study on self-harm in children aged 5–10 years in England[ 17 ]. Several variables showed the highest prevalence in the Emergent SIB and Persistent SIB groups, where prevalence is substantially higher than in the Transient SIB as well as No SIB groups. This was particularly notable for ADHD, anxiety, autism and depression in children, anxiety, depression and PTSD in the mothers, and ADHD and depression in the fathers. These patterns of particularly higher proportions in the Emergent and Persistent SIB groups were also seen across the adverse experience variables and the childhood developmental traits reported at both 3 and 8 years. Reported prevalence differences suggest that the underlying phenotype of Transient SIB may differ from the Emergent SIB . For several variables, the pattern of characteristics was more similar between the No SIB and the Transient SIB groups, such as the prevalences for parental diagnoses of anxiety and depression, maternal diagnoses of eating disorders and PTSD, paternal diagnoses of ADHD or the prevalence of depression in the children. Similarly, children with No SIB and Transient SIB showed more similar estimates for delayed motor development, abnormal speech development and trouble relating to others at the age of 3 years compared to those with Emergent and Persistent SIB . This suggests that the measure of SIB is capturing different underlying behaviours at these two ages. Some studies found SIB to be more common in children younger than five years of age with intellectual and developmental conditions. For instance, one study from the US, including infants at high familial risk of autism, found a prevalence for SIB of 32 and 39% at 12 and 24 months respectively[ 18 ]. The increased rates of anxiety diagnoses among children in the Emergent and Persistent SIB groups on the other hand indicate that SIB at the age of 8 years might be more associated with mental health conditions, which can be stand-alone as well as co-occur with neurodevelopmental conditions. A study on preschoolers in MoBa estimated that 33% of children with ADHD symptoms also reported anxiety symptoms[ 19 ]. In line with our findings, a meta-analysis from 2012, found that the most frequent conditions in adolescents presenting at hospitals after having self-harmed were depression, anxiety, and ADHD[ 20 ]. These findings strengthen the assumption that SIB in early childhood may also be associated with the co-occurrence of mental health and neurodevelopmental conditions in childhood and adolescence. These are indicators of the importance of psychological interventions and psychosocial support for families and children with neurodevelopmental and mental health conditions. Similar to our findings in the parents, a previous population and record-linkage study among 3- to14-year-old children and adolescents in New South Wales (Australia) found that those with self-harm had higher proportions of parental mental health and neurodevelopmental conditions, in particular depression, anxiety and ADHD[ 21 ]. These conditions are associated with affect regulation challenges and an increased parental experience of stress which can influence the parental ability and capacity to regulate their own emotions and to support their children with the development of emotional regulation skills[ 22 ]. These findings are in line with previous studies showing that parental mental health conditions may be subject to intergenerational transmission, both through a potentially higher genetic liability as well as the impact of mental health and neurodevelopmental conditions on the family environment[ 23 ]. The higher prevalence of being bullied, experiencing violence from other children as well as bullying others in the SIB groups are in line with findings from studies on children and adolescents aged 11 to 16 years in Wales as well as adolescents aged 16–17 years in Australia[ 24 ]. In a Norwegian cross-sectional study among 12 to 19-year-old adolescents, the risk of self-harm was three times higher for those who bullied others and five times higher for those who were bullied[ 25 ]. In mothers, the higher proportion of mothers reporting lifetime experience of sexual abuse in all SIB groups could potentially be mediated by maternal psychological distress as shown in a Japanese study on the impact of maternal adverse childhood experiences on their children[ 26 ]. Strengths and limitations This study has several strengths, including the large sample size, which allows us to examine the rare outcome of SIB in young children. Furthermore, MoBa questionnaire data is linked to registry data on mental health and neurodevelopmental diagnoses which enriches maternal reports and allows exploration of missingness to the SIB item. The availability of paternal self-report and registry data enables a more extensive picture of the family environment where previous studies often focus on maternal behaviours. However, several potential limitations are important to consider. First, the reported prevalence of SIB in the MoBa cohort is likely an underestimate of prevalence in the general population for several reasons. One of the possible explanations is that parents may not be fully aware of their child’s behaviours, and our study relied on the SIB prevalence on maternal reports only. Earlier studies on child mental health (e.g. anxiety) have shown that parental reports tend to be lower than the child’s self-reports[ 27 ], [ 28 ], [ 29 ]. Furthermore, longitudinal cohort studies like MoBa are affected by selection bias, with mental health conditions likely influencing participation and loss to follow-up[ 30 ]. Our missingness analysis revealed that those with and without SIB data at both 3 and 8 years differ significantly on both sociodemographic as well as mental health and neurodevelopmental factors. Mothers were less likely to respond to the SIB items when they or their child had a condition such as depression, anxiety or ADHD suggesting that reported prevalences of mental health diagnoses across SIB groups are also likely underestimated. Second, the SIB item used in the current study is part of the SCQ, which is a screening measure for neurodevelopmental traits, more specifically focusing on autistic traits[ 14 ]. This could potentially influence how the SIB item was interpreted by the mothers answering it. However, our pattern of results did not only show an association with autism diagnoses, but also with other mental health and neurodevelopmental conditions such as depression, anxiety and ADHD. Furthermore, previous studies have also used a single-item measure to examine SIB, such as in a sample of preschool children, 30 and 68 months old, in the United States with autism or other developmental delays and disorders where the SIB item from the SCQ[ 31 ] was also used, as well as a study on 6- to 17-year-olds using an item from the Child Behaviour Checklist to examine self-harm and suicidal attempts in three different samples in the United States, including autism groups and a general population sample[ 32 ]. The validation of the SIB item using the ADI-R interview item on SIB (supplementary table S7) shows high specificity and positive likelihood ratios on the one side, but also low sensitivity and negative likelihood ratios on the other side. The results indicate that mothers reporting SIB in MoBa at the age of three were also likely to report self-injury in the ABC study. At the same time, the SIB report at 3 years in MoBa is not as reliable in ruling out SIB. A possible explanation could be due to the restriction we introduced for the ABC study, the responses in the ABC study were limited to maximum one year after the 3-year questionnaire in MoBa was filled out. It is possible that some of the SIB emerged during that time. Third, our measure was also limited in that we only have maternal SIB reports, and further characteristics such as methods, motivations or frequency were not assessed. However, to our knowledge, this is the first description of SIB at such a young age in a longitudinal cohort study as large as MoBa, and future studies should expand upon this work with more detailed phenotyping of the phenomena. Future directions This explorative study describes the characteristics of children across groups with and without SIB at the ages of 3 and 8 years. Future studies should build on this work and include hypothesis testing to examine which potential risk and protective factors may influence the occurrence of SIB in young children and how these may change across more vulnerable groups. The results of this paper suggest that the SIB item not only identifies SIB potentially related to autism or other neurodevelopmental conditions but also SIB in children across different mental health and environmental conditions. The occurrence of SIB in those relevant samples, such as children with depression and anxiety diagnoses and those with a higher risk of developing mental health conditions, should be investigated further. Furthermore, follow-up research exploring outcomes in adolescence and adulthood is important to assess whether SIB in early childhood can be used as an early marker of later adverse outcomes, including self-harm and suicidal ideation and attempts. Conclusions In conclusion, children who show SIB at the young ages of 3 and 8 years were more likely to have received a diagnosis (anytime between birth and the year 2021) of a mental health or neurodevelopmental condition, particularly ADHD, anxiety, autism and depression and show higher proportions of developmental challenges such as delayed motor, speech and language development. Parents whose children showed SIB were also more likely to have a history of a diagnosed mental health condition, such as depression or anxiety. The prevalence of a mental health condition may potentially be adding to parental stress factors and therefore influencing the child’s family environment. Therefore, specific as well as global interventions to support families and create an inclusive environment that allows both, parents and children, to reduce potential internal and external risk factors of SIB may contribute to its risk reduction in early childhood. This will likely also contribute to a decrease in the risk of further development of mental health conditions in adolescence and adulthood, including the risk of suicide and suicide attempts. Declarations Author Contribution A.I. curated the data, ran formal analysis, developed methodology, was involved in project administration, wrote, reviewed and edited the main manuscript and prepared the figures and supplementary materials.R.E.W. and A.H. were involved in study conceptualization, data curation, funding acquisition, methodology, project administration, supervision, provided necessary resources and reviewed and edited the main manuscript incl. supplementary materials.L.I.S. and B.M. supervised the project, were involved in study conceptualization and funding acquisition, and reviewed and edited the manuscript incl. supplementary materials.L.J.H. was involved in study conceptualization and data curation, development of some of the used software, and reviewed and edited the manuscript incl. supplementary materials.K.S.L., A.S.Ø., H.A., G.D.S. and A.R. were involved in study conceptualization, and reviewed and edited the manuscript incl. supplementary materials. Acknowledgement The Norwegian Mother, Father and Child Cohort Study is supported by the Norwegian Ministry of Health and Care Services and the Ministry of Education and Research. We are grateful to all the participating families in Norway who take part in this ongoing cohort study. The Autism Birth Cohort Study provided the funding for the repetitive linkage between MoBa and NPR. This work was performed on the TSD (Tjeneste for Sensitive Data) facilities, owned by the University of Oslo, operated and developed by the TSD service group at the University of Oslo, IT Department (USIT) ( [email protected] ). Disclaimer. Data from the Norwegian Patient Registry has been used in this publication. The interpretation and reporting of these data are the sole responsibility of the authors, and no endorsement by the Norwegian Patient Registry is intended nor should be inferred. Data Availability Data from the Norwegian Mother, Father and Child Cohort Study is managed by the Norwegian Institute of Public Health. Access requires approval from the Regional Committees for Medical and Health Research Ethics (REC), compliance with GDPR, and data owner approval. Participant consent does not allow individual-level data storage in repositories or journals. Researchers seeking access for replication must apply via www.helsedata.no. References World Health Organization, Suicide worldwide in 2019: global health estimates . Geneva: World Health Organization, 2021. Accessed: Nov. 16, 2022. [Online]. Available: https://apps.who.int/iris/handle/10665/341728 B. Mars et al. , ‘Predictors of future suicide attempt among adolescents with suicidal thoughts or non-suicidal self-harm: a population-based birth cohort study’, Lancet Psychiatry , vol. 6, no. 4, Art. no. 4, Apr. 2019, doi: 10.1016/S2215-0366(19)30030-6. World Health Organization, Preventing suicide: a global imperative . Geneva: World Health Organization, 2014. Accessed: Apr. 11, 2023. [Online]. Available: https://apps.who.int/iris/handle/10665/131056 R. Carroll, C. Metcalfe, and D. Gunnell, ‘Hospital Presenting Self-Harm and Risk of Fatal and Non-Fatal Repetition: Systematic Review and Meta-Analysis’, PLoS ONE , vol. 9, no. 2, p. e89944, Feb. 2014, doi: 10.1371/journal.pone.0089944. Q. Xiao, X. Song, L. Huang, D. Hou, and X. Huang, ‘Global prevalence and characteristics of non-suicidal self-injury between 2010 and 2021 among a non-clinical sample of adolescents: A meta-analysis’, Front. Psychiatry , vol. 13, 2022, Accessed: Jul. 24, 2023. [Online]. Available: https://www.frontiersin.org/articles/10.3389/fpsyt.2022.912441 National Institute for Health and Care Excellence (NICE), Self-harm assessment, management and preventing recurrence . London: National Institute for Health and Care Excellence (NICE), 2022. E. Griffin, E. McMahon, F. McNicholas, P. Corcoran, I. J. Perry, and E. Arensman, ‘Increasing rates of self-harm among children, adolescents and young adults: a 10-year national registry study 2007–2016’, Soc. Psychiatry Psychiatr. Epidemiol. , vol. 53, no. 7, pp. 663–671, Jul. 2018, doi: 10.1007/s00127-018-1522-1. S. McManus et al. , ‘Prevalence of non-suicidal self-harm and service contact in England, 2000–14: repeated cross-sectional surveys of the general population’, Lancet Psychiatry , vol. 6, no. 7, pp. 573–581, Jul. 2019, doi: 10.1016/S2215-0366(19)30188-9. A. Reneflot, C. Haga, B. Engdahl, and K. Stene‐Larsen, ‘Sharp increase in self‐poisonings among adolescent girls during the Covid‐19 pandemic: Findings from Norwegian registry data’, Acta Psychiatr. Scand. , vol. 147, no. 6, pp. 634–636, Jun. 2023, doi: 10.1111/acps.13553. A. J. Tørmoen, M. Myhre, F. A. Walby, B. Grøholt, and I. Rossow, ‘Change in prevalence of self-harm from 2002 to 2018 among Norwegian adolescents’, Eur. J. Public Health , vol. 30, no. 4, pp. 688–692, Aug. 2020, doi: 10.1093/eurpub/ckaa042. D. McEvoy et al. , ‘Risk and protective factors for self-harm in adolescents and young adults: An umbrella review of systematic reviews’, J. Psychiatr. Res. , vol. 168, pp. 353–380, Dec. 2023, doi: 10.1016/j.jpsychires.2023.10.017. P. Magnus et al. , ‘Cohort Profile Update: The Norwegian Mother and Child Cohort Study (MoBa)’, Int. J. Epidemiol. , vol. 45, no. 2, pp. 382–388, Apr. 2016, doi: 10.1093/ije/dyw029. A. Havdahl et al. , ‘Age of walking and intellectual ability in autism spectrum disorder and other neurodevelopmental disorders: a population‐based study’, J. Child Psychol. Psychiatry , vol. 62, no. 9, pp. 1070–1078, Sep. 2021, doi: 10.1111/jcpp.13369. M. Rutter, Bailey, A., and Lord, C., ‘The Social Communication Questionnaire: Manual.’, Los Angeles, CA: Los Angeles, CA: Western Psychological Services., 2003. ‘R: The R Project for Statistical Computing’. Accessed: Jul. 11, 2024. [Online]. Available: https://www.r-project.org/ Hannigan, L., psychgen/phenotools . (Sep. 06, 2023). R. psychgen. Accessed: Jan. 26, 2024. [Online]. Available: https://github.com/psychgen/phenotools G. Geulayov et al. , ‘Self-harm in children 12 years and younger: characteristics and outcomes based on the Multicentre Study of Self-harm in England’, Soc. Psychiatry Psychiatr. Epidemiol. , vol. 57, no. 1, pp. 139–148, Jan. 2022, doi: 10.1007/s00127-021-02133-6. A. F. Dimian et al. , ‘Potential Risk Factors for the Development of Self-Injurious Behavior among Infants at Risk for Autism Spectrum Disorder’, J. Autism Dev. Disord. , vol. 47, no. 5, pp. 1403–1415, May 2017, doi: 10.1007/s10803-017-3057-9. K. R. Overgaard, H. Aase, S. Torgersen, and P. Zeiner, ‘Co-Occurrence of ADHD and Anxiety in Preschool Children’, J. Atten. Disord. , vol. 20, no. 7, pp. 573–580, Jul. 2016, doi: 10.1177/1087054712463063. K. Hawton, K. E. Saunders, and R. C. O’Connor, ‘Self-harm and suicide in adolescents’, The Lancet , vol. 379, no. 9834, pp. 2373–2382, Jun. 2012, doi: 10.1016/S0140-6736(12)60322-5. K. O’Hare et al. , ‘Parental and community risk factors for childhood self-harm thoughts and behaviours’, J. Affect. Disord. , vol. 310, pp. 279–283, Aug. 2022, doi: 10.1016/j.jad.2022.05.050. M. L. Zajicek-Farber, L. M. Mayer, and L. G. Daughtery, ‘Connections Among Parental Mental Health, Stress, Child Routines, and Early Emotional Behavioral Regulation of Preschool Children in Low-Income Families’, J. Soc. Soc. Work Res. , vol. 3, no. 1, pp. 31–50, Jan. 2012, doi: 10.5243/jsswr.2012.3. A. S. F. Kwong et al. , ‘Genetic and Environmental Risk Factors Associated With Trajectories of Depression Symptoms From Adolescence to Young Adulthood’, JAMA Netw. Open , vol. 2, no. 6, p. e196587, Jun. 2019, doi: 10.1001/jamanetworkopen.2019.6587. K. Ahmad et al. , ‘The impact of gender and age on bullying role, self-harm and suicide: Evidence from a cohort study of Australian children’, PLOS ONE , vol. 18, no. 1, p. e0278446, May 2023, doi: 10.1371/journal.pone.0278446. I. Myklestad and M. Straiton, ‘The relationship between self-harm and bullying behaviour: results from a population based study of adolescents’, BMC Public Health , vol. 21, no. 1, p. 524, Mar. 2021, doi: 10.1186/s12889-021-10555-9. S. Doi, T. Fujiwara, and A. Isumi, ‘Association between maternal adverse childhood experiences and mental health problems in offspring: An intergenerational study’, Dev. Psychopathol. , vol. 33, no. 3, pp. 1041–1058, Aug. 2021, doi: 10.1017/S0954579420000334. C. A. Burrows et al. , ‘Profiles and Correlates of Parent–Child Agreement on Social Anxiety Symptoms in Youth with Autism Spectrum Disorder’, J. Autism Dev. Disord. , vol. 48, no. 6, pp. 2023–2037, Jun. 2018, doi: 10.1007/s10803-018-3461-9. C. B. Kalvin et al. , ‘Discrepancies Between Parent and Child Ratings of Anxiety in Children With Autism Spectrum Disorder’, Autism Res. Off. J. Int. Soc. Autism Res. , vol. 13, no. 1, pp. 93–103, Jan. 2020, doi: 10.1002/aur.2220. T. May, K. Cornish, and N. J. Rinehart, ‘Parent-Child Agreement Using the Spence Children’s Anxiety Scale and a Thermometer in Children with Autism Spectrum Disorder’, Autism Res. Treat. , vol. 2015, pp. 1–9, 2015, doi: 10.1155/2015/315495. G. Biele et al. , ‘Bias from self selection and loss to follow-up in prospective cohort studies’, Eur. J. Epidemiol. , vol. 34, no. 10, Art. no. 10, Oct. 2019, doi: 10.1007/s10654-019-00550-1. G. N. Soke, S. A. Rosenberg, C. R. Rosenberg, R. A. Vasa, L.-C. Lee, and C. DiGuiseppi, ‘Brief Report: Self-Injurious Behaviors in Preschool Children with Autism Spectrum Disorder Compared to Other Developmental Delays and Disorders’, J. Autism Dev. Disord. , vol. 48, no. 7, pp. 2558–2566, Jul. 2018, doi: 10.1007/s10803-018-3490-4. C. M. Conner, J. Golt, G. Righi, R. Shaffer, M. Siegel, and C. A. Mazefsky, ‘A Comparative Study of Suicidality and Its Association with Emotion Regulation Impairment in Large ASD and US Census-Matched Samples’, J. Autism Dev. Disord. , vol. 50, no. 10, pp. 3545–3560, Oct. 2020, doi: 10.1007/s10803-020-04370-1. Additional Declarations No competing interests reported. Supplementary Files SupplementarytablesSIBinchildhood.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7235784","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":495718955,"identity":"2cd921d5-0ef4-4fa9-8609-df8353dbc002","order_by":0,"name":"Anastasia Izotova","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABAElEQVRIie3QMUvEMBTA8RcKujy4NaKkXyHl4BYLfpUGobfcLDdIyRGom64VP4ZfICVwt+iecrfIgXPkQDqJLSeKQ3qODvlPGfIjeQ8gFPrHIQCR++OxkvTgff1Nsl7XfyNf9YSKYTJ6UNuduy7ORjJS7q1Nxd39y6JpYcN8hG6WE6qXBqkmMqmyXFRroc4RXsfeZ2w2AX2kETpyiZkZw1qUpwBGSI+I7XTn9EeBcUdMT+KmLk/aAcLtjNO6jJBrslAdYdySkuIASezsij7fGkwMUaTKc5Y89bNw452F2emjm78XF2x1s3UuTZGtTN20c+Pd2E/R7w8fBqFQKBTy9wnHL1yHXpR6RAAAAABJRU5ErkJggg==","orcid":"","institution":"Lovisenberg Diaconal Hospital","correspondingAuthor":true,"prefix":"","firstName":"Anastasia","middleName":"","lastName":"Izotova","suffix":""},{"id":495718956,"identity":"7348a0bd-d2dc-4650-b99a-adc673dcb5d4","order_by":1,"name":"Line Indrevoll Stänicke","email":"","orcid":"","institution":"Lovisenberg Diaconal Hospital","correspondingAuthor":false,"prefix":"","firstName":"Line","middleName":"Indrevoll","lastName":"Stänicke","suffix":""},{"id":495718957,"identity":"34bbef23-9813-4cce-b22c-5dca3ca4f8be","order_by":2,"name":"Becky Mars","email":"","orcid":"","institution":"University of Bristol","correspondingAuthor":false,"prefix":"","firstName":"Becky","middleName":"","lastName":"Mars","suffix":""},{"id":495718959,"identity":"54500cac-569b-4906-bb34-a4b42435b4b3","order_by":3,"name":"Kim Stene-Larsen","email":"","orcid":"","institution":"Norwegian Institute of Public Health","correspondingAuthor":false,"prefix":"","firstName":"Kim","middleName":"","lastName":"Stene-Larsen","suffix":""},{"id":495718960,"identity":"ce136d9a-b91d-4b65-9068-a0e5deee2025","order_by":4,"name":"Laurie J. 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Wootton","email":"","orcid":"","institution":"Lovisenberg Diaconal Hospital","correspondingAuthor":false,"prefix":"","firstName":"Robyn","middleName":"E.","lastName":"Wootton","suffix":""}],"badges":[],"createdAt":"2025-07-28 16:09:54","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7235784/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7235784/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":88503789,"identity":"e79473f0-c309-43b5-85d5-b50d0367df7e","added_by":"auto","created_at":"2025-08-07 07:04:47","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":86355,"visible":true,"origin":"","legend":"\u003cp\u003eSociodemographic variables of the parents and child per SIB group in percent including confidence intervals of proportion (error bars). Abbreviations: m - mothers, f - fathers, c - children; bl - baseline-, 3y - 3-year-questionnaire, 8y - 8-year-questionnaire\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7235784/v1/8f5a5b13b506ef78357c9ff9.jpg"},{"id":88504973,"identity":"02c3586f-83e1-49d4-aa70-4a09c4e566c7","added_by":"auto","created_at":"2025-08-07 07:12:47","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":87879,"visible":true,"origin":"","legend":"\u003cp\u003eHealth-related behaviours of the parents; Abbreviations: m - mothers, f - fathers; bl – baseline questionnaire\u003c/p\u003e\n\u003cp\u003e*for minimum 3 months in the last 18 months\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7235784/v1/e6e9797ed0f2d61a4dbc655d.png"},{"id":88504967,"identity":"14038559-fa6e-4f63-8a88-785baa1eac97","added_by":"auto","created_at":"2025-08-07 07:12:47","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":145575,"visible":true,"origin":"","legend":"\u003cp\u003ea: Maternal mental health diagnoses - NPR 2008 to 2021; Abbreviations: m – mothers, ADHD - attention deficit hyperactivity disorder, BP – bipolar disorder, PTSD – post-traumatic stress disorder\u003c/p\u003e\n\u003cp\u003eb: Paternal mental health diagnoses - NPR 2008 to 2021; Abbreviations: f – fathers, ADHD - attention deficit hyperactivity disorder, BP – bipolar disorder, PTSD – post-traumatic stress disorder\u003c/p\u003e\n\u003cp\u003ec: Child’s mental health diagnoses - NPR 2008 to 2021; Abbreviations: c - children, ADHD - attention deficit hyperactivity disorder, PTSD – post-traumatic stress disorder\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7235784/v1/d69b1ae827584bef1931a8c9.png"},{"id":88504968,"identity":"2599718e-6522-455f-b7ff-329446a86b19","added_by":"auto","created_at":"2025-08-07 07:12:47","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":58050,"visible":true,"origin":"","legend":"\u003cp\u003eAdverse life experiences of the children at the age of 8 years and mothers at baseline; Abbreviations: m - mother, bl - baseline questionnaire\u003c/p\u003e","description":"","filename":"4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7235784/v1/d44b98910ac2441cd6cc483f.jpg"},{"id":88503785,"identity":"08bfdefd-3167-452a-812c-92cfda0b35b0","added_by":"auto","created_at":"2025-08-07 07:04:47","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":70335,"visible":true,"origin":"","legend":"\u003cp\u003ea: Developmental conditions in children at the age of 3 years\u003c/p\u003e\n\u003cp\u003eb: Developmental conditions in children at the age of 8 years\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7235784/v1/f0dd4e47877b0129b069df71.jpg"},{"id":108803839,"identity":"9b01faa4-7d4f-45d0-86b9-b49a9d746a3f","added_by":"auto","created_at":"2026-05-08 15:09:10","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":746865,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7235784/v1/f02d7826-2978-4afd-9e09-1a5e261c31c7.pdf"},{"id":88504971,"identity":"0e7f9012-4065-4c16-a92d-666bdb2cd225","added_by":"auto","created_at":"2025-08-07 07:12:47","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":91002,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementarytablesSIBinchildhood.docx","url":"https://assets-eu.researchsquare.com/files/rs-7235784/v1/c906e72396ad649647139409.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Self-Injurious Behaviour during Early Childhood in a General Population Sample – Exploratory Analysis in the Norwegian Mother, Father and Child Cohort Study (MoBa)","fulltext":[{"header":"Introduction","content":"\u003cp\u003eGlobally, suicide is the cause of death for more than 700,000 people every year and is the 4th most common cause of death among adolescents and young adults from ages 15 to 29 years[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Therefore, the focus on suicide prevention is an important priority for global health, and early prevention is crucial to decrease the number of suicide deaths. Self-harm was shown to be a strong predictor of the transition from suicidal thoughts to suicide attempts[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] and suicide [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Early self-harm prevention, recognition and treatment may therefore be important factors in reducing suicide rates as well as the development of other mental health conditions.\u003c/p\u003e\u003cp\u003eThe estimated lifetime prevalence of self-harm in adolescents varies greatly across different countries, study designs and samples, from around 4.3% up to 47.1%[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. The differences also depend on the definition and measurement of self-harm used across studies, geographic regions and research fields. Some definitions, such as the National Institute for Health and Care Excellence (NICE) guidelines in the UK[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], describe behaviours such as self-injury or self-poisoning as self-harm irrespective of the apparent purpose, whereas others make a distinction between self-harm that occurs with and without suicidal intent. Several studies suggest an increasing prevalence of self-harm, particularly among children and adolescents[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Tørmoen et al.[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] reported an increase in self-reported self-harm prevalence in the last 12 months from 4.1% in 2002 to 16.2% in 2018 among Norwegian 13-15-year-old adolescents. Little is known about the prevalence of self-harm behaviour among children below the age of 12 in general population samples.\u003c/p\u003e\u003cp\u003ePrevious research, predominantly focusing on adolescents and adults, has shown associations of self-harm with various psychosocial and sociodemographic factors such as depression, anxiety, peer-related victimisation, sex, family environment or educational attainment[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Studies on which factors are associated with self-harm in younger children remain limited. Better characterization of self-harm in younger children is necessary for more effective prevention, identification and treatment.\u003c/p\u003e\u003cp\u003eIn this study, we use the term ‘self-injurious behaviour’ (SIB), as this best reflects the behaviours captured by the questionnaire item available ‘Does your child ever injure himself/herself deliberately, such as by biting his/her arm or banging his/her head?’ - and data on the intention behind the act(s) was not available. We examined the occurrence of SIB at ages 3 and 8, including whether it was ‘\u003cem\u003etransient\u003c/em\u003e’ (only at age 3), ‘\u003cem\u003eemergent\u003c/em\u003e’ (only at age 8) or ‘\u003cem\u003epersistent\u003c/em\u003e’ (at both 3 and 8) across age. We also described the patterns of sociodemographic, neurodevelopmental and mental health factors for these SIB groups in early childhood.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eStudy Cohort\u003c/p\u003e\n\u003cp\u003eMoBa is a population-based pregnancy cohort study conducted by the Norwegian Institute of Public Health. Participants were recruited from all over Norway from 1999\u0026ndash;2008[\u003cspan class=\"CitationRef\"\u003e12\u003c/span\u003e]. The women consented to participation in 41% of the pregnancies. The cohort includes approximately 114,500 children, 95,200 mothers and 75,200 fathers. The establishment of MoBa and initial data collection was based on a license from the Norwegian Data Protection Agency and approval from The Regional Committees for Medical and Health Research Ethics. The MoBa cohort is currently regulated by the Norwegian Health Registry Act. The current study was approved by The Regional Committees for Medical and Health Research Ethics (REK project number: 2016/1702).\u003c/p\u003e\n\u003cp\u003eQuestionnaires were self-reported by mothers at baseline (15\u0026ndash;20 weeks of pregnancy), 3 years and 8 years, and by the fathers at baseline. Registry data was used from the Norwegian Patient Registry (NPR) and the Medical Birth Registry of Norway (MBRN). MBRN is a national health registry containing information about all births in Norway. NPR includes diagnoses received between 2008\u0026ndash;2021 in specialized healthcare services in hospitals, private and public outpatient clinics. Data from the Autism Birth Cohort (ABC) study was used to validate the SIB measure at 3 years. For the ABC study, parents participating in MoBa were invited for an in-person assessment of their children (n\u0026thinsp;=\u0026thinsp;1,306 invitations) based on specific criteria related to autistic traits, an autism diagnosis or having a sibling with an autism diagnosis as well as 915 children who were randomly selected as controls, with an overall participation rate of around 50%[\u003cspan class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e\n\u003cp\u003eLived Experience Interviews\u003c/p\u003e\n\u003cp\u003eWe conducted four lived experience interviews to inform the analysis plan. The interview questions were developed by the first author, followed by an in-depth team discussion and collective decision on their final form. The questions formed the interview guidelines which were accompanied by a debriefing section and a tailored consent form. Adults with lived experience of self-harm in childhood (4\u0026ndash;9 years) were recruited through social media and personal referrals. The participants provided written informed consent and received a gift card equalling 500 NOK as compensation for their time. Participants were asked about their thoughts and priorities for research on self-harm, including which risk and protective factors they considered important. The responses formed the decisions on variable inclusion in the analysis. There was a diversity of ethnic background and neurodiversity among the participants. However, all participants identified as female.\u003c/p\u003e\n\u003cp\u003eMeasures\u003c/p\u003e\n\u003cp\u003eAbbreviations used are explained in the supplementary materials (S1). All included measures are described in detail in S2 and summarised below.\u003c/p\u003e\n\u003cp\u003eSelf-injurious behaviour\u003c/p\u003e\n\u003cp\u003eSIB of the children was reported by the mothers using one item of the Social Communication Questionnaire (SCQ)[\u003cspan class=\"CitationRef\"\u003e14\u003c/span\u003e] at the ages of 3 and 8 years. The item \u0026lsquo;Does your child ever injure himself/herself deliberately, such as by biting his/her arm or banging his/her head?\u0026rsquo; was answered by the mothers with \u0026lsquo;yes\u0026rsquo; or \u0026lsquo;no\u0026rsquo;.\u003c/p\u003e\n\u003cp\u003eSIB item validation\u003c/p\u003e\n\u003cp\u003eAn interview question on SIB from the Autism Diagnostic Interview Revised (ADI-R) as part of the Autism Birth Cohort (ABC) study clinical assessment was used to validate the reported SIB in the questionnaire at 3 years. The responses to the ADI-R interview item were restricted to a maximum of one year after the 3-year questionnaire in MoBa was filled out by the mothers.\u003c/p\u003e\n\u003cp\u003eSociodemographic measures\u003c/p\u003e\n\u003cp\u003eSociodemographic measures included at baseline for both mothers and fathers were: age at child\u0026rsquo;s birth, child\u0026rsquo;s registered sex at birth, employment status, level of education (whether they achieved college or university degree) and whether Norwegian is the native language of the child\u0026rsquo;s parents or grandparents. The maternal living situation at baseline (whether or not they are living with their partner), civil status (mothers being married or in a cohabitant status with their partners) reported in the 3-years-questionnaire, and a variable on whether the mothers were living with the child\u0026rsquo;s father in the 8-years-questionnaire were also included, allowing for comparisons across groups on factors regarding the maternal living situation and civil status at the different ages of their child.\u003c/p\u003e\n\u003cp\u003eHealth-related behaviours in mothers and fathers\u003c/p\u003e\n\u003cp\u003eHealth-related behaviour measures included at baseline are alcohol consumption and smoking from both parents. Furthermore, measures of eating behaviours in mothers from the 3-years-questionnaire were included, featuring items on behaviours to control weight such as fasting, use of laxatives, vomiting and hard physical exercise as well as an item on binge eating.\u003c/p\u003e\n\u003cp\u003eMental health and neurodevelopmental conditions in mothers, fathers and children\u003c/p\u003e\n\u003cp\u003eDiagnostic groups were defined from registry data as having received an ICD-10 diagnostic code at least once for depression (F32, F33), anxiety disorders (F40, F41, F93), post-traumatic stress disorder (PTSD) (F43.1), bipolar disorder (BP) (F31), schizophrenia (F20), attention deficit hyperactivity disorder (ADHD) (F90), autism (F84.0, F84.1, F84.5, F84.8, F84.9) and eating disorders (F50).\u003c/p\u003e\n\u003cp\u003eAdverse life experiences in mothers and children\u003c/p\u003e\n\u003cp\u003eWe included variables from the 8-year questionnaire on the child\u0026rsquo;s experiences with bullying, being bullied and being subject to physical violence by other children. For the mothers, a variable on experience with sexual abuse was included from the baseline questionnaire.\u003c/p\u003e\n\u003cp\u003eDevelopmental characteristics in children\u003c/p\u003e\n\u003cp\u003eMeasures about the experience of developmental conditions or challenges included from the 3-years-questionnaire items on \u0026lsquo;delayed motor development\u0026rsquo;, \u0026lsquo;hyperactivity\u0026rsquo;, \u0026lsquo;abnormal speech development\u0026rsquo;, \u0026lsquo;sleep problems\u0026rsquo;, and \u0026lsquo;trouble relating to others\u0026rsquo;. Items included from the 8-years-questionnaire were \u0026lsquo;delayed psychomotor development\u0026rsquo;, \u0026lsquo;abnormal language development\u0026rsquo;, \u0026lsquo;hyperactivity\u0026rsquo;, \u0026lsquo;concentration or attention difficulties\u0026rsquo;, \u0026lsquo;autistic traits/autism/Asperger\u0026rsquo;s syndrome\u0026rsquo;, \u0026lsquo;behavioural problems (difficult and unruly)\u0026rsquo; and \u0026lsquo;emotional difficulties (sad or anxious)\u0026rsquo;.\u003c/p\u003e\n\u003ch2\u003eStatistical Analysis\u003c/h2\u003e\n\u003cp\u003eAnalyses were performed in R version 4.1.2[\u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e]. Diagnostic data and MoBa questionnaire variables were extracted and pre-processed using the \u003cem\u003ephenotools\u003c/em\u003e (v0.3.3) package[\u003cspan class=\"CitationRef\"\u003e16\u003c/span\u003e]. A detailed description of variable cleaning steps is given in S2.\u003c/p\u003e\n\u003cp\u003eWe included MoBa children with childbirth registered in MBRN whose mothers responded to the SIB item when the child was 3 and 8 years old. First, we estimated the prevalence of SIB in the MoBa cohort at child\u0026rsquo;s ages of 3 and 8 years. We analysed the responses and reported the prevalence and persistence of SIB, forming four mutually exclusive groups: \u003cem\u003eNo SIB (\u003c/em\u003eanswered with \u0026lsquo;no\u0026rsquo; at 3 and 8 years\u003cem\u003e)\u003c/em\u003e, \u003cem\u003eTransient SIB (\u003c/em\u003eanswered with \u0026lsquo;yes\u0026rsquo; at 3 years only\u003cem\u003e)\u003c/em\u003e, \u003cem\u003eEmergent SIB (\u003c/em\u003eanswered with \u0026lsquo;yes\u0026rsquo; at 8 years only\u003cem\u003e)\u003c/em\u003e and \u003cem\u003ePersistent SIB (\u003c/em\u003eanswered with \u0026lsquo;yes\u0026rsquo; at 3 and 8 years). Next, we described the sociodemographic, mental health and neurodevelopmental factors across each of the four groups using percentages with confidence intervals for binary variables and means with 95% confidence intervals for the continuous variables.\u003c/p\u003e\n\u003cp\u003eThis was an exploratory analysis, and the results are primarily descriptive. We examined the general pattern of results to describe the characteristics of the groups including those children who self-injured at different ages. We used independent sample chi square tests to compare prevalence of the characteristics in each of the self-injury groups to the \u003cem\u003eNo SIB\u003c/em\u003e group. Our results aim to generate hypotheses that can be tested in future analyses.\u003c/p\u003e\n\u003cp\u003eTo explore the potential impact of missing data, we conducted a sensitivity analysis comparing responders with non-responders at the child ages of 3 and 8 years for the following key demographic variables: mother living with a partner (at baseline), maternal employment status (at baseline), maternal highest educational attainment (at baseline), and only for 8 years, SIB reported at 3 years. Furthermore, we compared the diagnoses of mental health and neurodevelopmental conditions of the mothers and the children from NPR. Additionally, we examined the prevalence of SIB in absolute numbers and percentages per birth year to explore potential time effects.\u003c/p\u003e"},{"header":"Results","content":"\u003ch4\u003ePrevalence and persistence of SIB\u003c/h4\u003e\n\u003cp\u003eMothers responded for a total of 35,494 children in MoBa to the SIB item at both time points (3 and 8 years). As per the maternal report, 91.7% (\u003cem\u003en\u003c/em\u003e=32,543) of the children did not show SIB at any of the assessed time points. The prevalence of \u003cem\u003eTransient SIB\u003c/em\u003e (age 3 only) was 6.6% (\u003cem\u003en\u003c/em\u003e=2,336), \u003cem\u003eEmergent SIB\u003c/em\u003e (age 8 only) was 1.2% (\u003cem\u003en\u003c/em\u003e=434) and \u003cem\u003ePersistent SIB\u003c/em\u003e (both time points) was 0.5% (\u003cem\u003en\u003c/em\u003e=181).\u0026nbsp;\u003c/p\u003e\n\u003ch4\u003eProportions of examined variables\u003c/h4\u003e\n\u003cp\u003eA detailed overview of all the proportions of the\u0026nbsp;examined variables (sociodemographic variables, health-related behaviours in parents, mental health and neurodevelopmental conditions in mothers, fathers and children, measures of adverse life experiences in mothers and children, and mother-reported developmental conditions in the 3- and 8-year-old children) across each of the four groups is reported in the S3.\u003c/p\u003e\n\u003ch4\u003eSociodemographic characteristics\u0026nbsp;\u003c/h4\u003e\n\u003cp\u003eThe mean age at child\u0026rsquo;s birth was significantly lower for both parents in all of the SIB groups in comparison to the \u003cem\u003eNo SIB\u0026nbsp;\u003c/em\u003egroup. The lowest mean age was in the \u003cem\u003ePersistent SIB\u003c/em\u003e group. The parental mean age (SD) across all groups can be found in the S4.\u003c/p\u003e\n\u003cp\u003eBinary sociodemographic variables of the parents as well as the child\u0026rsquo;s sex are reported in Figure 1. The same pattern of results was found across most of the sociodemographic variables, except for child sex, where the highest proportion of male children was observed for the \u003cem\u003eEmergent SIB\u003c/em\u003e group. The proportion of living with a partner at baseline (mother), being married/cohabiting at the child\u0026rsquo;s age of 3 years (mother), parents living together at the child\u0026rsquo;s age of 8 years, holding a university degree (mother and father), being employed (mother and father), and Norwegian being the native language of the parents and grandparents was highest in the \u003cem\u003eNo SIB\u003c/em\u003e group, and lowest in the \u003cem\u003ePersistent SIB\u003c/em\u003e group. Paternal university degree was not significantly different for \u003cem\u003eTransient SIB\u003c/em\u003e in comparison to the \u003cem\u003eNo SIB\u003c/em\u003e group.\u003c/p\u003e\n\u003ch4\u003eHealth-related behaviours in the parents\u003c/h4\u003e\n\u003cp\u003eHealth-related behaviours of the parents across the SIB groups are reported in Figure 2. \u0026nbsp;Maternal smoking during pregnancy was more frequent in the SIB groups (9% for \u003cem\u003eTransient SIB\u003c/em\u003e, 10.6% for \u003cem\u003eEmergent SIB\u003c/em\u003e, and 11.4% for \u003cem\u003ePersistent SIB\u003c/em\u003e) compared to the \u003cem\u003eNo SIB\u003c/em\u003e (5.5%) group. The self-reported proportion of smoking among fathers during their partner\u0026rsquo;s pregnancy was between 35.7% (\u003cem\u003ePersistent SIB\u003c/em\u003e) and 43.9% (\u003cem\u003eEmergent SIB\u003c/em\u003e). Mothers reported in the 3-years-questionnaire on behaviours aimed to control weight that they experienced in the last 18 months. The highest proportions were reported for the items on binge-eating behaviour (26.1% \u003cem\u003ePersistent SIB\u003c/em\u003e) and using hard exercise to control weight (17% \u003cem\u003eEmergent\u003c/em\u003e\u003cem\u003e\u0026nbsp;SIB\u003c/em\u003e). The differences in alcohol consumption were not significant for both parents across all SIB groups compared to the \u003cem\u003eNo SIB\u003c/em\u003e group. Maternal report of hard exercise did not differ significantly for the \u003cem\u003ePersistent SIB\u003c/em\u003e from the \u003cem\u003eNo SIB\u003c/em\u003e group as well as the proportion of those who reported to use vomiting to control weight was not significantly different in the \u003cem\u003eEmergent SIB\u003c/em\u003e compared the \u003cem\u003eNo SIB\u003c/em\u003e group.\u003c/p\u003e\n\u003ch4\u003eMental health and neurodevelopmental conditions in mothers, fathers, and children\u003c/h4\u003e\n\u003cp\u003eMental health and neurodevelopmental conditions in parents and children across the SIB groups are reported in Figure 3. Across maternal diagnoses registered in NPR \u0026ndash; Figure 3 - panel A, the proportion was highest for the \u003cem\u003eEmergent SIB\u003c/em\u003e and \u003cem\u003ePersistent SIB\u003c/em\u003e groups.\u0026nbsp;The most prevalent condition in the mothers was depression (14.8% \u003cem\u003eEmergent SIB)\u003c/em\u003e, followed by anxiety disorder (10.8% \u003cem\u003eEmergent SIB)\u0026nbsp;\u003c/em\u003eand PTSD (5% \u003cem\u003ePersistent SIB).\u0026nbsp;\u003c/em\u003eEating disorders did not differ significantly in the\u003cem\u003e\u0026nbsp;Transient SIB\u0026nbsp;\u003c/em\u003egroup from the\u003cem\u003e\u0026nbsp;No SIB\u003c/em\u003e group\u003cem\u003e.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eFor the fathers\u0026nbsp;\u0026ndash; Figure 3 - panel B, the overall rates of registered diagnoses were low, so not all percentages could be reported. Depression had the highest prevalence (7% \u003cem\u003eEmergent\u003c/em\u003e and 8.5% \u003cem\u003ePersistent SIB\u003c/em\u003e), followed by anxiety (5.9% \u003cem\u003eEmergent SIB\u003c/em\u003e) and ADHD (5.6% \u003cem\u003ePersiste\u003c/em\u003e\u003cem\u003ent SIB\u003c/em\u003e).\u003c/p\u003e\n\u003cp\u003eIn children, Figure 3 \u0026ndash; panel C, ADHD was the most prevalent condition (21.2% \u003cem\u003eEmergent SIB\u003c/em\u003e, 19.3% \u003cem\u003ePersistent SIB\u003c/em\u003e), followed by anxiety (9.9%) and autism (9.4%) in the \u003cem\u003ePersistent SIB\u003c/em\u003e group. Across child diagnoses, prevalences were highest for the \u003cem\u003eEmergent\u003c/em\u003e and \u003cem\u003ePersistent SIB\u003c/em\u003e groups, with rates of diagnoses in the \u003cem\u003eTransient SIB\u003c/em\u003e group looking more similar to the \u003cem\u003eNo SIB\u003c/em\u003e group. Depression and eating disorders did not differ significantly between the \u003cem\u003eEmergent\u0026nbsp;\u003c/em\u003eand the \u003cem\u003eNo SIB\u003c/em\u003e group.\u0026nbsp;\u003c/p\u003e\n\u003ch4\u003eMeasures for adverse life experiences in mothers and children\u003c/h4\u003e\n\u003cp\u003eAdverse life experiences in mothers and children are shown in Figure 4. The proportion of 8-year-olds who were bullied by other children was three times higher in the \u003cem\u003eEmergent SIB\u0026nbsp;\u003c/em\u003e(21.3%) and \u003cem\u003ePersistent SIB\u003c/em\u003e (21.8%) groups compared to \u003cem\u003eNo SIB\u003c/em\u003e (6.8%). The proportion of those who bullied others was also highest in the \u003cem\u003eEmergent SIB\u003c/em\u003e (7.4%) and \u003cem\u003ePersistent SIB\u003c/em\u003e (11%) groups. Reported experienced violence by other children showed an overall similar pattern to the \u0026lsquo;bullying other children\u0026rsquo; item.\u003c/p\u003e\n\u003cp\u003eMaternal experience of sexual abuse was reported by 16.4% of the mothers in the \u003cem\u003eNo SIB\u0026nbsp;\u003c/em\u003egroup. The proportion increased by about one-third in the \u003cem\u003eTransient SIB\u0026nbsp;\u003c/em\u003egroup and nearly doubled in the groups \u003cem\u003eEmergent SIB\u0026nbsp;\u003c/em\u003e(31.6%) and \u003cem\u003ePersistent SIB\u0026nbsp;\u003c/em\u003e(32%).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe differences were significant across all variables and for all SIB groups compared to the \u003cem\u003eNo SIB\u003c/em\u003e group in this category.\u003c/p\u003e\n\u003ch4\u003eMother reported developmental conditions in the 3- and 8-year-old children\u003c/h4\u003e\n\u003cp\u003eConditions related to the child\u0026rsquo;s development at the ages of 3 and 8 years and reported by the mothers are shown in Figure 5, panels A and B.\u003c/p\u003e\n\u003cp\u003eAs reported in the 3-year questionnaire, \u0026lsquo;Sleep problems\u0026rsquo; were about 3.5 times more frequent in the \u003cem\u003ePersistent SIB\u0026nbsp;\u003c/em\u003e(14%) than in the \u003cem\u003eNo SIB\u003c/em\u003e (4.1%) group. Similarly, \u0026lsquo;abnormal speech development\u0026rsquo; had the lowest proportion in the \u003cem\u003eNo SIB\u003c/em\u003e (3.3%) group and increased about 3.75 times in the \u003cem\u003ePersistent SIB\u0026nbsp;\u003c/em\u003e(12.5%) group. The proportion of \u0026lsquo;delayed motor development\u0026rsquo; was almost six times higher in the \u003cem\u003ePersistent SIB\u003c/em\u003e (11.9%) than in the \u003cem\u003eNo SIB\u003c/em\u003e (2%) group. While the proportion of \u0026lsquo;trouble relating to others\u0026rsquo; is very low in the \u003cem\u003eNo SIB\u0026nbsp;\u003c/em\u003e(0.2%) group and overall not very high in the other groups, it is 26 times higher in the \u003cem\u003ePersistent SIB\u003c/em\u003e (4.5%) group. Also, the proportion of \u0026lsquo;hyperactivity\u0026rsquo; is 15 times higher in the \u003cem\u003ePersistent SIB\u003c/em\u003e (4.5%) compared to the \u003cem\u003eNo SIB\u003c/em\u003e (0.3%) group.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAll the reported items on developmental conditions in the 8-years-questionnaire show similarities in the proportion patterns - with the \u003cem\u003eNo SIB\u003c/em\u003e group showing the lowest proportion, the \u003cem\u003eTransient SIB\u0026nbsp;\u003c/em\u003egroup showing a moderately increased proportion and the \u003cem\u003eEmergent SIB\u0026nbsp;\u003c/em\u003eas well as \u003cem\u003ePersistent SIB\u003c/em\u003e groups showing the highest proportion. For instance, \u0026lsquo;Concentration or attention difficulties\u0026rsquo; were reported for 7.3% of the children in the \u003cem\u003eNo SIB\u003c/em\u003e group, almost doubling the proportion for the \u003cem\u003eTransient\u003c/em\u003e \u003cem\u003eSIB\u0026nbsp;\u003c/em\u003e(14.6%) group and being more than 4.5 times higher in the \u003cem\u003eEmergent SIB\u003c/em\u003e (33.1%) and \u003cem\u003ePersistent SIB\u003c/em\u003e (35%) groups. The proportion for the \u0026lsquo;concentration or attention difficulties\u0026rsquo; item is also the highest reported proportion in this category, closely followed by \u0026lsquo;behavioural problems\u0026rsquo; (34.5% in the \u003cem\u003ePersistent SIB\u003c/em\u003e group) and \u0026lsquo;emotional difficulties\u0026rsquo; (32.8% in the \u003cem\u003ePersistent SIB\u003c/em\u003e group).\u003c/p\u003e\n\u003cp\u003ePrevalences for all the reported variables at the ages of 3 and 8 years differ significantly across all SIB groups compared to the \u003cem\u003eNo SIB\u003c/em\u003e group.\u003c/p\u003e\n\u003ch4\u003eSensitivity analysis\u003c/h4\u003e\n\u003cp\u003eSIB item responders have been compared to non-responders for the 3-year- and 8-year-questionnaire across selected sociodemographic variables as well as mental health and neurodevelopmental conditions (S5). Mothers who were non-responders were less likely to live with a partner, be employed and hold a university degree. Furthermore, non-responding mothers were more likely to be diagnosed with the majority of the selected mental health and neurodevelopmental conditions. Children with a missing response to the SIB item at the age of 8 years were more likely to receive a diagnosis of any of the included conditions, while non-responders at the age of 3 did not significantly differ from responders for diagnoses of autism, eating disorder or schizophrenia. Additionally, the prevalence of SIB was analysed per birth year \u0026ndash; showing a small, but inconsistent increase from the early to the latest inclusion years in MoBa (S6). \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSelf-injurious behaviour at three years \u0026ndash; item validation\u003c/p\u003e\n\u003cp\u003eTo test the validity of the SCQ item assessing SIB at the age of three, we cross-validated the available data with responses to the ADI-R interview item on SIB that were available through the ABC study. The participants in the ABC study are a sub-sample from the MoBa sample. We ran specificity and sensitivity analyses which show a high specificity and positive likelihood ratios on the one hand, and low sensitivity and negative likelihood ratios on the other hand (S7). The high specificity shows that the SCQ item is a useful measure of the presence of SIB. However, the low sensitivity indicates that it is not as good at capturing the absence of SIB. One of the possible explanations can be that we restricted the ABC study measurement to maximum one year past the MoBa data collection of the 3-year questionnaire and that the SIB measured in the ABC study may have occurred after the MoBa questionnaire was filled out. \u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn the present study, we investigated the prevalence and persistence of childhood SIB in the MoBa cohort and described the sociodemographic as well as mental health and neurodevelopmental characteristics of children who did self-injure compared to those who did not. The prevalence of SIB among children in the MoBa cohort reported at either 3 years only, 8 years only or both ages was 8.3%. The majority of characteristics showed a consistent pattern of results, with SIB groups tending to show a higher prevalence of low socioeconomic status, higher rates of mental health and neurodevelopmental diagnoses, and more developmental difficulties than the \u003cem\u003eNo SIB\u003c/em\u003e group.\u003c/p\u003e\u003cp\u003eAmong sociodemographic characteristics, the proportion of parents living with partners, being employed, holding a university degree as well as having Norwegian as their or their parents\u0026rsquo; native language was slightly lower in the SIB groups compared to no SIB. The majority of children with reported SIB were male which is in line with previous findings in a recent study on self-harm in children aged 5\u0026ndash;10 years in England[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eSeveral variables showed the highest prevalence in the \u003cem\u003eEmergent SIB\u003c/em\u003e and \u003cem\u003ePersistent SIB\u003c/em\u003e groups, where prevalence is substantially higher than in the \u003cem\u003eTransient SIB\u003c/em\u003e as well as \u003cem\u003eNo SIB\u003c/em\u003e groups. This was particularly notable for ADHD, anxiety, autism and depression in children, anxiety, depression and PTSD in the mothers, and ADHD and depression in the fathers. These patterns of particularly higher proportions in the \u003cem\u003eEmergent\u003c/em\u003e and \u003cem\u003ePersistent SIB\u003c/em\u003e groups were also seen across the adverse experience variables and the childhood developmental traits reported at both 3 and 8 years. Reported prevalence differences suggest that the underlying phenotype of \u003cem\u003eTransient SIB\u003c/em\u003e may differ from the \u003cem\u003eEmergent SIB\u003c/em\u003e. For several variables, the pattern of characteristics was more similar between the \u003cem\u003eNo SIB\u003c/em\u003e and the \u003cem\u003eTransient SIB\u003c/em\u003e groups, such as the prevalences for parental diagnoses of anxiety and depression, maternal diagnoses of eating disorders and PTSD, paternal diagnoses of ADHD or the prevalence of depression in the children.\u003c/p\u003e\u003cp\u003eSimilarly, children with \u003cem\u003eNo SIB\u003c/em\u003e and \u003cem\u003eTransient SIB\u003c/em\u003e showed more similar estimates for delayed motor development, abnormal speech development and trouble relating to others at the age of 3 years compared to those with \u003cem\u003eEmergent\u003c/em\u003e and \u003cem\u003ePersistent SIB\u003c/em\u003e. This suggests that the measure of SIB is capturing different underlying behaviours at these two ages. Some studies found SIB to be more common in children younger than five years of age with intellectual and developmental conditions. For instance, one study from the US, including infants at high familial risk of autism, found a prevalence for SIB of 32 and 39% at 12 and 24 months respectively[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. The increased rates of anxiety diagnoses among children in the \u003cem\u003eEmergent\u003c/em\u003e and \u003cem\u003ePersistent SIB\u003c/em\u003e groups on the other hand indicate that SIB at the age of 8 years might be more associated with mental health conditions, which can be stand-alone as well as co-occur with neurodevelopmental conditions. A study on preschoolers in MoBa estimated that 33% of children with ADHD symptoms also reported anxiety symptoms[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn line with our findings, a meta-analysis from 2012, found that the most frequent conditions in adolescents presenting at hospitals after having self-harmed were depression, anxiety, and ADHD[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. These findings strengthen the assumption that SIB in early childhood may also be associated with the co-occurrence of mental health and neurodevelopmental conditions in childhood and adolescence. These are indicators of the importance of psychological interventions and psychosocial support for families and children with neurodevelopmental and mental health conditions. Similar to our findings in the parents, a previous population and record-linkage study among 3- to14-year-old children and adolescents in New South Wales (Australia) found that those with self-harm had higher proportions of parental mental health and neurodevelopmental conditions, in particular depression, anxiety and ADHD[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. These conditions are associated with affect regulation challenges and an increased parental experience of stress which can influence the parental ability and capacity to regulate their own emotions and to support their children with the development of emotional regulation skills[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. These findings are in line with previous studies showing that parental mental health conditions may be subject to intergenerational transmission, both through a potentially higher genetic liability as well as the impact of mental health and neurodevelopmental conditions on the family environment[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe higher prevalence of being bullied, experiencing violence from other children as well as bullying others in the SIB groups are in line with findings from studies on children and adolescents aged 11 to 16 years in Wales as well as adolescents aged 16\u0026ndash;17 years in Australia[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. In a Norwegian cross-sectional study among 12 to 19-year-old adolescents, the risk of self-harm was three times higher for those who bullied others and five times higher for those who were bullied[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. In mothers, the higher proportion of mothers reporting lifetime experience of sexual abuse in all SIB groups could potentially be mediated by maternal psychological distress as shown in a Japanese study on the impact of maternal adverse childhood experiences on their children[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eStrengths and limitations\u003c/p\u003e\u003cp\u003eThis study has several strengths, including the large sample size, which allows us to examine the rare outcome of SIB in young children. Furthermore, MoBa questionnaire data is linked to registry data on mental health and neurodevelopmental diagnoses which enriches maternal reports and allows exploration of missingness to the SIB item. The availability of paternal self-report and registry data enables a more extensive picture of the family environment where previous studies often focus on maternal behaviours.\u003c/p\u003e\u003cp\u003eHowever, several potential limitations are important to consider. First, the reported prevalence of SIB in the MoBa cohort is likely an underestimate of prevalence in the general population for several reasons. One of the possible explanations is that parents may not be fully aware of their child\u0026rsquo;s behaviours, and our study relied on the SIB prevalence on maternal reports only. Earlier studies on child mental health (e.g. anxiety) have shown that parental reports tend to be lower than the child\u0026rsquo;s self-reports[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e], [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e], [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Furthermore, longitudinal cohort studies like MoBa are affected by selection bias, with mental health conditions likely influencing participation and loss to follow-up[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. Our missingness analysis revealed that those with and without SIB data at both 3 and 8 years differ significantly on both sociodemographic as well as mental health and neurodevelopmental factors. Mothers were less likely to respond to the SIB items when they or their child had a condition such as depression, anxiety or ADHD suggesting that reported prevalences of mental health diagnoses across SIB groups are also likely underestimated.\u003c/p\u003e\u003cp\u003eSecond, the SIB item used in the current study is part of the SCQ, which is a screening measure for neurodevelopmental traits, more specifically focusing on autistic traits[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. This could potentially influence how the SIB item was interpreted by the mothers answering it. However, our pattern of results did not only show an association with autism diagnoses, but also with other mental health and neurodevelopmental conditions such as depression, anxiety and ADHD. Furthermore, previous studies have also used a single-item measure to examine SIB, such as in a sample of preschool children, 30 and 68 months old, in the United States with autism or other developmental delays and disorders where the SIB item from the SCQ[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e] was also used, as well as a study on 6- to 17-year-olds using an item from the Child Behaviour Checklist to examine self-harm and suicidal attempts in three different samples in the United States, including autism groups and a general population sample[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. The validation of the SIB item using the ADI-R interview item on SIB (supplementary table S7) shows high specificity and positive likelihood ratios on the one side, but also low sensitivity and negative likelihood ratios on the other side. The results indicate that mothers reporting SIB in MoBa at the age of three were also likely to report self-injury in the ABC study. At the same time, the SIB report at 3 years in MoBa is not as reliable in ruling out SIB. A possible explanation could be due to the restriction we introduced for the ABC study, the responses in the ABC study were limited to maximum one year after the 3-year questionnaire in MoBa was filled out. It is possible that some of the SIB emerged during that time. Third, our measure was also limited in that we only have maternal SIB reports, and further characteristics such as methods, motivations or frequency were not assessed. However, to our knowledge, this is the first description of SIB at such a young age in a longitudinal cohort study as large as MoBa, and future studies should expand upon this work with more detailed phenotyping of the phenomena.\u003c/p\u003e\u003cp\u003eFuture directions\u003c/p\u003e\u003cp\u003eThis explorative study describes the characteristics of children across groups with and without SIB at the ages of 3 and 8 years. Future studies should build on this work and include hypothesis testing to examine which potential risk and protective factors may influence the occurrence of SIB in young children and how these may change across more vulnerable groups. The results of this paper suggest that the SIB item not only identifies SIB potentially related to autism or other neurodevelopmental conditions but also SIB in children across different mental health and environmental conditions. The occurrence of SIB in those relevant samples, such as children with depression and anxiety diagnoses and those with a higher risk of developing mental health conditions, should be investigated further. Furthermore, follow-up research exploring outcomes in adolescence and adulthood is important to assess whether SIB in early childhood can be used as an early marker of later adverse outcomes, including self-harm and suicidal ideation and attempts.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eIn conclusion, children who show SIB at the young ages of 3 and 8 years were more likely to have received a diagnosis (anytime between birth and the year 2021) of a mental health or neurodevelopmental condition, particularly ADHD, anxiety, autism and depression and show higher proportions of developmental challenges such as delayed motor, speech and language development. Parents whose children showed SIB were also more likely to have a history of a diagnosed mental health condition, such as depression or anxiety. The prevalence of a mental health condition may potentially be adding to parental stress factors and therefore influencing the child\u0026rsquo;s family environment. Therefore, specific as well as global interventions to support families and create an inclusive environment that allows both, parents and children, to reduce potential internal and external risk factors of SIB may contribute to its risk reduction in early childhood. This will likely also contribute to a decrease in the risk of further development of mental health conditions in adolescence and adulthood, including the risk of suicide and suicide attempts.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eA.I. curated the data, ran formal analysis, developed methodology, was involved in project administration, wrote, reviewed and edited the main manuscript and prepared the figures and supplementary materials.R.E.W. and A.H. were involved in study conceptualization, data curation, funding acquisition, methodology, project administration, supervision, provided necessary resources and reviewed and edited the main manuscript incl. supplementary materials.L.I.S. and B.M. supervised the project, were involved in study conceptualization and funding acquisition, and reviewed and edited the manuscript incl. supplementary materials.L.J.H. was involved in study conceptualization and data curation, development of some of the used software, and reviewed and edited the manuscript incl. supplementary materials.K.S.L., A.S.\u0026Oslash;., H.A., G.D.S. and A.R. were involved in study conceptualization, and reviewed and edited the manuscript incl. supplementary materials.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe Norwegian Mother, Father and Child Cohort Study is supported by the Norwegian Ministry of Health and Care Services and the Ministry of Education and Research. We are grateful to all the participating families in Norway who take part in this ongoing cohort study. The Autism Birth Cohort Study provided the funding for the repetitive linkage between MoBa and NPR. This work was performed on the TSD (Tjeneste for Sensitive Data) facilities, owned by the University of Oslo, operated and developed by the TSD service group at the University of Oslo, IT Department (USIT) ([email protected]). Disclaimer. Data from the Norwegian Patient Registry has been used in this publication. The interpretation and reporting of these data are the sole responsibility of the authors, and no endorsement by the Norwegian Patient Registry is intended nor should be inferred.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eData from the Norwegian Mother, Father and Child Cohort Study is managed by the Norwegian Institute of Public Health. Access requires approval from the Regional Committees for Medical and Health Research Ethics (REC), compliance with GDPR, and data owner approval. Participant consent does not allow individual-level data storage in repositories or journals. Researchers seeking access for replication must apply via www.helsedata.no.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eWorld Health Organization, \u003cem\u003eSuicide worldwide in 2019: global health estimates\u003c/em\u003e. Geneva: World Health Organization, 2021. Accessed: Nov. 16, 2022. [Online]. Available: https://apps.who.int/iris/handle/10665/341728\u003c/li\u003e\n\u003cli\u003eB. 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Disord.\u003c/em\u003e, vol. 20, no. 7, pp. 573\u0026ndash;580, Jul. 2016, doi: 10.1177/1087054712463063.\u003c/li\u003e\n\u003cli\u003eK. Hawton, K. E. Saunders, and R. C. O\u0026rsquo;Connor, \u0026lsquo;Self-harm and suicide in adolescents\u0026rsquo;, \u003cem\u003eThe Lancet\u003c/em\u003e, vol. 379, no. 9834, pp. 2373\u0026ndash;2382, Jun. 2012, doi: 10.1016/S0140-6736(12)60322-5.\u003c/li\u003e\n\u003cli\u003eK. O\u0026rsquo;Hare \u003cem\u003eet al.\u003c/em\u003e, \u0026lsquo;Parental and community risk factors for childhood self-harm thoughts and behaviours\u0026rsquo;, \u003cem\u003eJ. Affect. Disord.\u003c/em\u003e, vol. 310, pp. 279\u0026ndash;283, Aug. 2022, doi: 10.1016/j.jad.2022.05.050.\u003c/li\u003e\n\u003cli\u003eM. L. Zajicek-Farber, L. M. Mayer, and L. G. Daughtery, \u0026lsquo;Connections Among Parental Mental Health, Stress, Child Routines, and Early Emotional Behavioral Regulation of Preschool Children in Low-Income Families\u0026rsquo;, \u003cem\u003eJ. Soc. 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J. Epidemiol.\u003c/em\u003e, vol. 34, no. 10, Art. no. 10, Oct. 2019, doi: 10.1007/s10654-019-00550-1.\u003c/li\u003e\n\u003cli\u003eG. N. Soke, S. A. Rosenberg, C. R. Rosenberg, R. A. Vasa, L.-C. Lee, and C. DiGuiseppi, \u0026lsquo;Brief Report: Self-Injurious Behaviors in Preschool Children with Autism Spectrum Disorder Compared to Other Developmental Delays and Disorders\u0026rsquo;, \u003cem\u003eJ. Autism Dev. Disord.\u003c/em\u003e, vol. 48, no. 7, pp. 2558\u0026ndash;2566, Jul. 2018, doi: 10.1007/s10803-018-3490-4.\u003c/li\u003e\n\u003cli\u003eC. M. Conner, J. Golt, G. Righi, R. Shaffer, M. Siegel, and C. A. Mazefsky, \u0026lsquo;A Comparative Study of Suicidality and Its Association with Emotion Regulation Impairment in Large ASD and US Census-Matched Samples\u0026rsquo;, \u003cem\u003eJ. Autism Dev. Disord.\u003c/em\u003e, vol. 50, no. 10, pp. 3545\u0026ndash;3560, Oct. 2020, doi: 10.1007/s10803-020-04370-1.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"MoBa, MBRN, childhood self-harm, self-injury, longitudinal, mental health","lastPublishedDoi":"10.21203/rs.3.rs-7235784/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7235784/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjective\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSelf-harm is one of the strongest risk factors for suicide and a major public health concern. Most existing research has focused on adolescents and adults. Knowledge about the prevalence and correlates of self-harm in children is limited.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethod\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eLived experience interviews informed the analysis plan. In the Norwegian Mother, Father and Child Cohort Study (MoBa), mothers reported on self-injurious behaviour (SIB) at age 3 and 8 years (N=35,494): ‘Does your child ever injure himself/herself deliberately, such as by biting his/her arm or banging his/her head?’. We examined the prevalence of SIB and the prevalence patterns of sociodemographic, neurodevelopmental and mental health factors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMothers answered ‘yes’ on the SIB item at age 3 only (‘\u003cem\u003etransient\u003c/em\u003e’) for 6.6% (\u003cem\u003en\u003c/em\u003e=2,336) of the children, 1.2% (\u003cem\u003en\u003c/em\u003e=434) at 8 years only (‘\u003cem\u003eemergent\u003c/em\u003e’), and 0.5% (\u003cem\u003en\u003c/em\u003e=181) at both 3 and 8 years (‘\u003cem\u003epersistent\u003c/em\u003e’). We observed different patterns of sociodemographic, mental health, and neurodevelopmental factors for all SIB groups compared to \u003cem\u003eNo SIB\u003c/em\u003e, with individuals in the \u003cem\u003eEmergent\u003c/em\u003e and \u003cem\u003ePersistent SIB\u003c/em\u003e groups often most distinct from those reporting no SIB. Several factors also distinguished these two groups - most notably rates of paternal depression diagnoses and reports of children's motor developmental delay and sleep problems.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eGroups reporting SIB in childhood had a higher prevalence of mental health and neurodevelopmental conditions. This pattern differed depending on when SIB first emerged and whether it persisted. Future studies should investigate the potential underlying mechanisms for the reported prevalence patterns and their implications for SIB prevention in children.\u003c/p\u003e","manuscriptTitle":"Self-Injurious Behaviour during Early Childhood in a General Population Sample – Exploratory Analysis in the Norwegian Mother, Father and Child Cohort Study (MoBa)","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-07 07:04:42","doi":"10.21203/rs.3.rs-7235784/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"33985c39-e9ff-4a96-9d4d-39c4a8c94dce","owner":[],"postedDate":"August 7th, 2025","published":true,"recentEditorialEvents":[{"type":"decision","content":"Rejected","date":"2026-05-04T18:19:52+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-04T18:24:38+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-07 07:04:42","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7235784","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7235784","identity":"rs-7235784","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}