The literature is inconsistent regarding whether childhood ADHD confers risk for adulthood problematic alcohol use, depressive symptoms, and their co-occurrence. These inconsistencies could be due to meaningful heterogeneity in the adulthood outcomes of children with ADHD that were obscured in traditional group-based analyses. The current study tested this possibility, as well as the contribution of adulthood ADHD symptom persistence, in order to clarify long-term risk in this population. Children diagnosed with ADHD and demographically-similar children without ADHD were followed longitudinally into adulthood and repeatedly assessed on heavy drinking, alcohol problems, and depressive symptoms from ages 21-29 (84.1% White (not Hispanic); 86.9% male; 51.2% childhood ADHD; 14.7% adulthood-persistent ADHD; N = 320). Group-based multi-trajectory modeling identified six groups with different combinations of trajectories across these variables. Heterogeneous longitudinal outcomes for those with ADHD were found. Some children with ADHD showed increased risk as typically predicted, with a higher likelihood of membership in a group with stable-moderate alcohol outcomes and stable-severe depression (adulthood persistent ADHD also predicted this group), whereas some children with ADHD were more likely to belong to a group with virtually no alcohol outcomes and low depression. Additionally, adulthood persistent ADHD predicted membership in a group with stable-severe alcohol outcomes and stable-moderate depression. Given the severity associated with co-occurring alcohol and depressive disorders, studies of early risk and protective factors and long-term outcomes for these disparate trajectory patterns are needed, particularly for those with childhood and persisting ADHD.
Keywords: ADHD; Alcohol; Comorbidity; Depression; Trajectory groups.