Examining the longitudinal associations between individual differences and mental health in adolescence and young adulthood: Results from a UK birth cohort study

Introduction: With the rising global burden of mental health issues – namely depression and anxiety – particularly among adolescents and young adults, it is crucial to investigate the factors that influence the development of these mental health outcomes over the life course. Here, we explored the associations between individual differences – personality and cognitive ability – in adolescence with mental health problems in later adolescence and young adulthood using longitudinal data from a UK birth cohort study (the Avon Longitudinal Study of Parents and Children; ALSPAC). Methods: Personality was measured at age 13 using the ‘Big-5’ personality questionnaire, with cognitive ability assessed at age 15 via the Weschler abbreviated scale of intelligence. ICD-10 classifications for mild depression and generalised anxiety disorder were assessed at ages 17 and 24 via the computerised clinical interview schedule (revised). Results: In logistic regression models adjusted for a range of relevant sociodemographic and prior mental health confounders, higher extraversion and emotional stability scores were associated with lower rates of depression and anxiety, while higher openness to experience scores were associated with increased rates. Agreeableness, conscientiousness and cognitive ability had little-to-no association with mental health outcomes. Results were largely consistent at both ages 17 and 24, and when using multiple imputation to account for missing data and potential selection bias.Conclusion: By using a large-scale longitudinal cohort with a range of relevant confounders, these results provide further evidence that personality traits may potentially cause subsequent mental health outcomes and could be used to help identify high-risk individuals.