Abstract
Background: Attention-deficit hyperactivity disorder (ADHD) in childhood is associated with various adverse long-term outcomes.
Aims: We aimed to examine the independent associations between ADHD symptoms at age 14-16 years and long-term mental health and psychosocial functioning outcomes in a 40-year birth cohort study.
Method: Study members from the Christchurch Health and Development Study, a population-based New Zealand birth cohort study (N = 1265 at birth) were followed to age 40 years. Generalised estimating equations were used to model associations between ADHD symptoms at age 14-16 years and outcomes at age 18-40. Adjusted models were fitted to account for confounding by antecedent individual and familial risk factors, and coexisting symptoms of conduct disorder or oppositional defiant disorder.
Results: Adolescents in the highest quartile for ADHD symptoms at age 14-16 years were at elevated risk of substance use disorder, depression, suicidal ideation, criminal offending and unemployment across early adulthood. They also had lower income, home ownership, relationship stability and living standards. The size of these associations attenuated after adjusting for confounding factors and the effect of coexisting conduct disorder and oppositional defiant disorder. However, in adjusted models, ADHD symptoms remained associated with elevated odds of substance use and criminal offending outcomes, with odds ratios ranging from 1.4 to 1.6.
Conclusions: Higher levels of adolescent ADHD symptoms are associated with substance use problems and criminal offending in adulthood. Long-term secondary prevention activities are needed to detect and manage coexisting problems among adults with a history of ADHD.