Changes in the adult consequences of adolescent mental health: findings from the 1958 and 1970 British birth cohorts

Objective: To investigate whether the associations between adolescent externalising and internalising mental health difficulties and mid-life health and social outcomes are changing across cohorts. Methods: Data from 31,349 participants followed as part of two prospective national birth cohort studies: 1958 National Child Development Study (n=16091) and the 1970 British Cohort Study (n=15258). Adolescent mental health at age 16 years was assessed using the Rutter scales and operationalised as both a traditional 2-factor internalising and externalising and as a hierarchical bi-factor. Associations between adolescent psychopathology and health and wellbeing (mental health, general health, life satisfaction) and socio-economic (cohabitation, voting behaviour, education and employment) outcomes at ages 42 are estimated and illustrated across cohorts. Results: The prevalence of adolescent mental health difficulties increased between those born in 1958 and 1970. Their associations with different midlife outcomes became more severe or remained similar in the 1970 compared the 1958 cohort. For instance, a stronger association with adolescent mental health difficulties was found for those born in 1970, compared with those born in 1958 for midlife psychological distress (OR 1970=1.82 [1.65;1.99], OR 1958=1.60 [1.43;1.79], cohabitation (OR 1970=0.64 [0.59;0.70], OR 1958=0.74 [1.43;1.79]), and professional occupations (OR 1970=0.75 [0.67;0.84], OR 1958=1.05 [0.88;1.24]). A hierarchical bi-factor approach to modelling adolescent mental health indicated that the associations of externalising symptoms with later outcomes were mainly explained by their shared variance with internalising symptoms. Conclusion: A strengthening trend in the associations of adolescent mental health with adverse mid-life outcomes across two generations highlights the individual and societal burden of adolescent mental health problems might be increasing. If this trend continues to apply to more recently born cohorts, the wide-ranging implications of the increasing prevalence in adolescent mental health difficulties currently observed should be recognised and increased public health efforts to minimise adverse outcomes are needed.