“Late-onset” ADHD symptoms in young adulthood: Is this ADHD?
Lucy Riglin, Robyn E. Wootton, Lucy A. Livingston, Jessica Agnew‐Blais, Louise Arseneault, Rachel Blakey, Sharifah Shameem Agha, K. Langley, Stephan Collishaw, Michael O‘Donovan, George Davey Smith, Evie Stergiakouli, Kate Tilling, Anita Thapar
Abstract
Objective: We investigated whether “late-onset” ADHD that emerges in adolescence/adulthood is similar in risk factor profile to: (1) child-onset ADHD, but emerges later because of scaffolding/compensation from childhood resources; and (2) depression, because it typically onsets in adolescence/adulthood and shows symptom and genetic overlaps with ADHD. Methods: We examined associations between late-onset ADHD and ADHD risk factors, cognitive tasks, childhood resources and depression risk factors in a population-based cohort followed-up to age 25 years ( N=4224–9764). Results: Parent-rated late-onset ADHD was like child-onset persistent ADHD in associations with ADHD polygenic risk scores and cognitive task performance, although self-rated late-onset ADHD was not. Late-onset ADHD was associated with higher levels of childhood resources than child-onset ADHD and did not show strong evidence of association with depression risk factors. Conclusions: Late-onset ADHD shares characteristics with child-onset ADHD when parent-rated, but differences for self-reports require investigation. Childhood resources may delay the onset of ADHD.