Intermittent 3-day depressions and suicidal behaviour.

Intermittent short-lived episodes of depression were examined in a group of 20 recurrent suicidal attempters without major depression, classified misleadingly as borderline personality disorders on DSM-IIIR, during careful prospective follow-up for between 4 and 6 months. The duration of depressions clustered tightly around a median of 3 days with two thirds lasting between 2 and 4 days. They occurred erratically and unpredictably with a median interval of 18 days and were seen to be moderate to severe measured on the MADRS in 70% of episodes.