A critical review was given to the diagnostic transition of hyperactive children, i.e., from attention deficit disorder to attention deficit-hyperactivity disorder, in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders. Based on the new diagnostic criteria for hyperactive children, or hyperkinetic disorders in ICD-10, 12 of 122 (9.8%) children with a birthweight less than 1,500 grams have found to show hyperkinetic disorders during ordinary follow-up examinations at 4 to 6 years of age. Discontinuation of stimulants during school holidays, or the "drug holidays" procedure, was recommended not only because a child's response to stimulants could be reconfirmed but also because the side effect of growth retardation could be avoided. Three typical drug responders with hyperactivity were presented. Case 1 was a 19-year-old male with some autistic features and tics. He had been taking pemoline from 10 to 13 years of age, but showed no side effects. Case 2 was a 15-year-old boy with epileptic EEG abnormalities, and had been also taking pemoline from 6 to 10. He was attacked by a partial seizure with secondary generalization just 2 months after the drug administration. Recurrence of epileptic seizures was prevented by additional medication of an anticonvalsant , carbamazepine. Case 3 was a 13-year-old boy with enuresis nocturna and with several febrile seizures, and had been taking clomipramine, a tricyclic antidepressant, from 4 to 6. The antidepressant proved very effective to his hyperactivity and temper tantrum, but not to his enuresis.