The tricyclic antidepressive agents are still the drugs of choice because of their reliable action and the percentage of successes obtained (60 to 75%), especially in major depressions with deep melancholia. The course of antidepressive drugs is well documented, any depression needs at least three to four months' maintenance treatment after an initial phase of one month's treatment, frequently intravenous treatment is required. Current research is aimed at providing tricyclic agents without anticholinergic activity, the cause of most of their undesirable side-effects.