During a period of 20 years (1968-1988) all inpatients admitted for the first time to the adolescent psychiatric unit in Copenhagen (n = 841) were classified in accordance with social and psychiatric variables, to describe the clientele as a group and, furthermore, to investigate changes occurring during that period. The total clientele had a broad age range (12-21 years), with as many as 36% less than 15 years old. Eleven percent of the patients had attempted suicide before admission. Fifty-six percent of the total group were diagnosed as psychotic or as borderline cases. The patients came predominantly from lower social levels, and almost half the group had a child debut defined as symptoms that had resulted in referral for further investigation during childhood. Moreover, among the schizophrenic patients 35% had an early onset. The age of onset may have some clinical significance, as this item was related to several sociodemographic variables. Finally, an increase in the rate of psychoses and lower social class was recorded during the period.