The antidepressive and anxiolytic efficacy of flupenthixol has been investigated in numerous controlled and open trials involving patients with endogenous, reactive as well as senile depressions. When administered at a mean daily single or multiple dose of 1-2 mg, flupenthixol proved to be a very effective and well-tolerated antidepressant. As opposed to some of the currently available antidepressants, flupenthixol has a rapid onset of action which is often displayed within the first 2-3 days following its application. Flupenthixol decanoate has also a pronounced antidepressive and anxiolytic effect which appears to be adequate enough for treating mild to moderately severe syndromes of depression. This depot neuroleptic has been given at a fortnightly dosage ranging between 2.5 and 30 mg. However, if the aspect of efficacy in relation to tolerance has to be taken in to consideration, then 5 mg are apt to be an appropriate dose. Patients with an agitated depression and/or suicide ideation should, however, be excluded from therapy with this drug. Extrapyramidal movement disorders which may appear during treatment are a disadvantage of this medication. Apparently such disorders are rarely encountered if the dose is kept below 10 mg. Other untoward effects are very seldom indeed. A final and conclusive judgement on the possible application of flupenthixol decanoate in the prophylaxis of phases in patients with bipolar and periodical depressions is as yet not feasible. Further clinical trials are necessary before flupenthixol decanoate can be classified as a possible 'depot antidepressant'.