The symptoms of the disorder are hyperactivity, impulsiveness and attention deficits but children with ADHD may also have oppositional defiant disorder, conduct disorder, anxiety, depression, specific learning difficulties and sleep disorders.
Einkenni röskunarinnar eru ofvirkni, hvatvísi og athyglisbrestur en oft glíma einstaklingar með ADHD einnig við mótþróaröskun, hegðunarröskun, kvíða eða þunglyndi, sértæka námserfiðleika, svefntruflanir og fleira.