The clinical picture of adult hyperkinetic syndrome (HKS) or attention deficit/hyperactivity disorder is nearly unknown in Germany. It can be estimated, that approximately one third of affected children also show symptoms as adults. In the combined type of the syndrome symptoms of inattention as well as of hyperactivity and impulsivity are present, a predominantly inattentive or hyperactive-impulsive type is possible. Retrospective diagnosis of HKS in childhood can be difficult. Disorganization, emotional disturbances and stress intolerance are common in adults with HKS as well as residual symptoms of learning disorders like dyslexia, dyscalculia and dysgraphia. In differential diagnosis especially affective, anxiety and antisocial personality disorders have to be considered, for which on the other side a frequent comorbidity with HKS is known. There is strong evidence for genetic transmission. Neurobiological findings revealed dysregulation of neurotransmitters. For treatment stimulants as pemoline and methamphetamin are effective, in addition tricyclic antidepressants or beta blockers; positive effects are probable for moclobemide, bupropion, fluoxetine and venlafaxine.