Features of recurrent brief depression.

Recurrent brief depression, characterised by frequently occurring brief depressive episodes, lasting less than two weeks, is now recognised as a common and disabling illness with a chronic relapsing course and a significant suicide risk. The episodes have a mean duration of 3 days, but otherwise fulfill the symptomatic criteria for DSM III-R major depression. Some two thirds of episodes satisfy severity criteria for at least moderate depression and about a third for severe depression. They recur erratically with a mean period of 18 days between the start of one episode and the next. Because of the frequency of the episodes patients may report longer continuous periods of depression than was the case and may be mistakenly perceived as dysthymia as major depression. It is important to identify these patients as treatment response appears to differ. The episodes are too short to be able to assume efficacy with conventional antidepressants; it is necessary to adopt a prophylactic strategy for treatment aiming to reduce the severity, the frequency, or the duration of episodes.