Roxindole is a potent autoreceptor-"selective" dopamine agonist originally developed for the treatment of schizophrenic syndromes. The drug also inhibits 5-HT uptake and has 5-HT1A agonistic actions. In this open clinical trial 12 in-patients suffering from a major depressive episode (DSM-III-R) were treated with roxindole for 28 days in a fixed dosage of 15 mg per day. A reduction of at least 50% in HAMD-17 total scores was observed in 8 out of 12 patients after 4 weeks (mean HAMD-17 reduction of 56% in all patients), while 4 patients did not respond to roxindole treatment. Half of the patients showed a complete psychopathological remission (HAMD-17 < 8). Roxindole's onset of antidepressant action was remarkably rapid. Seven out of eight responders improved within the first 2 weeks of treatment (at least 50% decrease in HAMD-17 total score), and four patients were nearly asymptomatic within 1 week. Our results indicate that roxindole may possess potent antidepressant properties and that its efficacy should be further evaluated by double-blind controlled studies against reference drugs.