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

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. Building on earlier work that has examined early life predictors of ADHD symptom trajectories up to age 14, we applied latent class growth analysis to data from the UK Millennium Cohort Study (N = 10,262) to evaluate whether developmental trajectories of ADHD symptoms up to age 17 (from age 3) were similar to those identified up to age 14 and associated with differing levels of impairment in peer victimisation, mental health, substance use, and delinquency outcomes at age 17. 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. By the end of mid-adolescence, those with a later onset have similar impairments to those following an early onset/persistent trajectory. Residual impairment may remain for those on a remitting trajectory.

Developmental trajectories of ADHD symptoms in a large population-representative longitudinal study.

BACKGROUND: Previous research has suggested that there is substantial heterogeneity in the developmental trajectories of attention-deficit/hyperactivity disorder (ADHD) symptoms. Sometimes, qualitative distinctions between trajectories with different ages of onset and/or patterns of remission are made; however, little is known about the predictors and broader clinical meaningfulness of these candidate 'developmental subtypes' of ADHD symptoms. METHODS: We applied latent class growth analysis to data from the UK Millennium Cohort Study (MCS; N = 11 316; ages 3, 5, 7, 11 and 14) to evaluate whether developmental trajectories of ADHD symptoms differing in early life predictors could be identified. Our optimal model included six trajectory groups, labelled unaffected (34.9% of the sample), mildly affected (24.1%), subclinical remitting (12.8%), pre-school onset partially remitting (14.1%), developmentally increasing (7.6%) and pre-school onset persistent (6.4%). RESULTS: Factors such as gender, conduct problems, cognitive ability, maternal education, premature birth, peer problems and school readiness scores differentiated between specific ADHD symptom trajectories. CONCLUSIONS: Taken together, our findings provide preliminary evidence that distinguishing different trajectories of ADHD symptoms could be clinically informative.