Attention deficit hyperactivity disorder (ADHD) is considered a neurologic development disorder resulting in impairment of attention and inhibitory control, manifested as attention deficit, hyperactivity, impulsiveness; symptoms should develop between age six and twelve and have to persist for more than six months. Approximately 30-50% of the diagnosed cases are manifesting the disorder during adulthood and 2.5-5% of the adults are suffering of ADHD. Genetics are important factors in ADHD, being involved in 75% of the cases, as well in the persistence of ADHD during adult life. Three subtypes of ADHD are described--one in which is predominating the attention deficit, one with predominant hyperactivity and impulsiveness and a third combined subtype. Diagnosis criteria in ADHD are established by the American Psychiatric Association (DSM criteria) and by World Health Organization. Differential diagnosis is mainly considering bipolar disorder and borderline personality disorder. Management of ADHD is including behavioral therapies and medication, alone or combined. Stimulant medications such as amphetamine represent the therapy of choice, being effective in 80% of the cases. New data are underlying the need for following up of the cases during adulthood, since the risk for development of psychiatric conditions such as depression, anxiety, as well as the suicidal behavior is higher than in the general population.