Prevalence of Non-suicidal Self-injury (NSSI) in Chinese Psychiatric Patients diagnosed according to DSM-5: A Cross-Sectional Epidemiological Study

Background: NSSI is a common behavior among psychiatric patients that is easily overlooked and often brings serious consequences. The current literature is limited to certain groups of people and uses different diagnostic criteria, so the prevalence of this behavior is unknown. The aim of this study was to investigate the prevalence of NSSI in patients with mental disorders in China using DSM-5 diagnostic criteria. Methods: A two-week multi-center cross-sectional survey was conducted in 15 specialized psychiatric hospitals or general hospitals (including outpatients and inpatients) from 14 cities in 8 provinces of China. DSM-5 diagnostic criteria were used to investigate the presence of NSSI behavior in all patients with mental disorders who came to their psychiatry departments. Findings: A total of 3,298 patients with mental disorders were included in the study. The prevalence of NSSI was 6.8% in outpatients and 6.5% in inpatients. There were significant differences in the prevalence of NSSI among different age groups (χ2=187.461, p<0.000). The highest prevalence of NSSI behavior was found in adolescents aged 10-19 years (14.3%), followed by young adults aged 20-29 years (7.0%). The prevalence of NSSI behavior in females was significantly higher than in males (P=16.9 %, χ2=31.322, p<0.000) (P=19.6 %, χ2=11.723, p=0.001) (P=5.9 %, χ2=6.094, p=0.014) ((P=7.7 %, χ2=14.472, p<0.000). The prevalence of NSSI behavior in patients with Personality disorders was significantly higher than in any other diagnostic group (P=46.7%, χ2=195.239, p<0.000). Interpretation: The prevalence of NSSI in patients with mental disorders is high, especially in adolescents. Therefore, it is necessary to inform patients and medical workers how to effectively treat and manage NSSI in order to reduce its occurrence.