AGAINST: Adult ADHD is a valid condition requiring “clinical attention”!

Attention deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder with onset in childhood. DSM-5 requires several symptoms to be present before age 12. A controversial idea in recent years has been “adult-onset ADHD.” However, evidence supporting this construct remains weak. Most reported cases rely on retrospective adult self-report, lack collateral childhood data, or fail to rule out mimicking conditions (e.g., anxiety, depression, sleep disorders, substance use, medical and neurological causes). Methodological limitations include recall bias, non-equivalent assessment tools across life stages, and insufficient exclusion of alternative explanations. Longitudinal cohorts suggest that most purported “adult-onset” cases had earlier subthreshold or atypical difficulties. The balance of current evidence indicates that “pure” adult-onset ADHD is, at best, rare, and more often reflects missed childhood ADHD or symptomatic overlaps with other conditions. This commentary summarizes methodological flaws, alternative explanations, and critical views that caution against acceptance of adult-onset ADHD as a distinct nosological entity.