Late adolescent outcomes of different developmental trajectories of ADHD symptoms in a large longitudinal study

Background: There exists substantial heterogeneity in the developmental trajectories of ADHD symptoms, with distinctions often made between persistent versus remittent, and early- versus late-onset. However, how these trajectories relate to late adolescent functioning and whether, in particular, later onset trajectories mark a milder subtype remains unclear. Methods: We applied latent class growth analysis to data from the UK Millennium Cohort Study (N = 16,703) to evaluate whether developmental trajectories of ADHD symptoms (ages 3-17) were associated with differing levels of impairment in peer problems, mental health, substance use, and delinquency at age 17. Results: Our optimal model included five trajectory groups, labelled unaffected (37.6%), mildly affected (34.8%), subclinical remitting (14.4%), adolescent onset (7.6%), and stable high (5.6%). Adolescent onset and stable high trajectories were similarly impaired across all outcomes, other than substance use. Subclinical remitting individuals were impaired on self-esteem and well-being compared to unaffected individuals. Conclusions: By adolescence, those with a later onset have similar impairments to those following an early onset/persistent trajectory. Residual impairment remains for those on a remitting trajectory.