Links between cognition and functioning: Examining the role of mental health in clinically ascertained and population-based samples

Background Cognitive function is a significant predictor of health and mortality in the population. Common mental health problems, such as depression and anxiety, are associated with both cognitive impairments and increased functional impairment. This study aimed to examine the relationship between cognition, mental health and functioning across two cohorts.

Participants were recruited from an online population cohort, HealthWise Wales (N=3,679), and a psychiatric cohort, the National Centre for Mental Health (NCMH, N=1,036), to complete a cognitive battery and the World Health Organisation Disability Assessment Schedule (WHODAS). We assessed the associations between cognitive performance and the WHODAS, as well as two measures of life functioning: current employment and cohabitation with a partner. We examined the role of current mood, education and health/lifestyle factors using linear and logistic regression.

Higher cognitive performance was associated with fewer functional difficulties on the WHODAS (HealthWise Wales: B=-0.12, 95%CI[-0.15,-0.09], P<0.001; NCMH: B=-0.1, 95%CI[-0.13,-0.08], P<0.001), being in employment or education (HealthWise Wales: OR=1.22, 95%CI[1.11,1.34], P<0.001; NCMH: OR=1.31, 95%CI[1.19,1.46], P<0.001) and living with a partner (HealthWise Wales only: OR=1.19, 95%CI[1.06,1.32], P=0.003). Higher levels of depression and anxiety symptoms were consistently associated with reduced functioning across all analyses. The relationship between cognition and functioning remained significant but attenuated after accounting for these symptoms.

Cognitive function was associated with functioning in both samples. This association may be partially explained by current symptoms of depression and anxiety. Both cognitive function and common mental health problems may be potential intervention targets to alleviate daily difficulties. Competing Interest Statement JTRW has received funding from Takeda Pharmaceuticals for research unrelated to this study. JTRW and IRJ have received funding from Akrivia Health for research unrelated to this study. AJL, JTRW and IRJ designed and developed the cognitive assessment (CONCA) used in this study. Funding Statement This study was funded by the National Centre for Mental Health (NCMH), a collaboration between Cardiff, Swansea and Bangor Universities The development of the CONCA battery was supported by two MRC grants (MC PC 17212 and MC PC 17170) and the Wellcome Trust (214601/Z/18/Z) Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The School of Medicine Research Ethics Committee of Cardiff University gave ethical approval for this work (reference 15/64). Wales Research Ethics Committee 2 gave ethical approval for the National Centre for Mental Health (reference 16/WA/0323). Wales Research Ethics Committee 3 gave ethical approval for HealthWise Wales (reference 15/WA/0076). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data Availability CONCA data on NCMH participants are available online in the MRC Centre for Neuropsychiatric Genetics and Genomics Walters Group Data Repository at https://walters.psycm.cf.ac.uk. Authors are not able to share data from the NCMH or HealthWise Wales cohorts directly due to restrictions. Data on the wider NCMH sample are available through direct application to NCMH (see https://www.ncmh.info for contact details). The HealthWise Wales dataset is available through HealthWise Wales on reasonable request (https://www.healthwisewales.gov.wales/for-researchers/).