In a systematic clinical study, indluding four uncontrolled clinical trials with psychiatric patients belonging to four different diagnostic groups, trazodone, the first triazolopyridine compound subjected to clinical investigation, was found to be a therapeutically effective psychoactive drug. Since the most consistent therapeutic action of trazodone was seen to be in the depressive syndrome, i.e., Guilt Feelings, Motor Retardation and Depressive Mood, it was suggested that trazodone has a therapeutic effect on depressive symptoms whether they occur in depression, neurosis, organic brain syndrome or schizophrenia.