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

BackgroundCognitive 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. MethodsParticipants 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. ResultsHigher 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. ConclusionsCognitive 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.