Preliminary open trials performed by the authors and others with Moclobemide, a new MAO-A inhibitor, indicated that the drug has a satisfactory antidepressant activity In the present double-blind study Moclobemide has been compared to placebo in a group of 34 unipolar psychotic or neurotic depressed patients. The mean daily dose of Moclobemide was 297 mg and treatment lasted from two to four weeks. Drug effectiveness was measured by improvements in the Hamilton Rating Scale for Depression (HRSD), Clinical Global Impression (CGI) and 100 mm Visual Analogue Scale (VAS). The results have shown that the active drug was markedly superior to placebo. The mean total score of HRSD was reduced from 41.7 to 16.5 in 18 pts. treated with Moclobemide and from 36.3 to 29.1 in 16 pts. who received placebo. Self-assessment with VAS showed a mean reduction from 82.7 mm to 42.2 mm and from 84.3 to 70.6 mm respectively. Moderate to marked improvement was observed by the CGI in 15 cases treated with Moclobemide and mild to moderate in 5 cases who received placebo. The treatment was well tolerated. Moclobemide, ein neuer MAO-A-Hemmstoff, wurde in einer Doppelblindstudie gegen Plazebo bei 34 endogen-depressiven (unipolarer Typ) oder neurotisch-depressiven Patienten geprüft. Die mittlere tägliche Dosis betrug 297 mg und die Behandlung dauerte 2 bis 4 wochen. Die Wirksamkeit der Behandlung wurde mittels der Hamilton-Depressions-Bewertungsskala, dem klinischen Globalurteil und der visuellen Analogskala überprüft. Die Ergebnisse zeigen eine deutliche Überlegenheit der Prüfsubstanz gegenüber Plazebo und eine gute Verträglichkeit.