Thanks to progress in the diagnosis and treatment of depression it is now possible for most cases to be treated on an out-patient basis. Only 15–20% of patients require hospitalisation, most of them because their depression has proved resistant to therapy. To overcome therapy-resistance the following methods of treatment are available: (1) In therapy-resistant endogenous and psychogenic depressions, mono-infusion therapy is the treatment of choice; it can also be administered on an out-patient basis. (2) In extremely intractable cases, it is advisable to resort to combined infusion therapy, preceded by five days of relaxation therapy with oral doses of a neuroleptic, and possibly reinforced by medication with 5-hydroxytryptophan (the precursor of serotonin) or by sleep deprival. (3) In therapy-resistant cases of so-called masked depression, marked by overtones of anxiety and hypochondriasis, infusions of maprotiline are indicated, because this anti-depressant exerts a relaxing and mildly anxiolytic action, has a stabilising influence on the autonomic nervous system, and produces a mood-brightening effect. (4) In patients who are apathetic and devoid of drive and suffering from involutional depression or depression of old age, infusion therapy plus administration of an MAO inhibitor can be recommended. (5) Combination of an antidepressant with a neuroleptic agent also displaying certain antidepressive properties is really indicated only in the rare cases of schizo-affective psychosis. (6) Electroconvulsive therapy should be employed only as a last resort in extremely retarded and apathetic patients with strong suicidal tendencies, and the indication for ECT should be established with the utmost reserve.