HETEROGENEITY OF DEPRESSION - CLASSIFICATION OF DEPRESSIVE SUBTYPES BY LONGITUDINAL COURSE

This paper describes the application of prospective longitudinal data from an epidemiological sample of young adults to define subtypes of m ajor depression. Depression was classified on a spectrum from subthres hold manifestation of symptoms and duration at one end, to cases with recurrent episodes of depression meeting duration criteria for major d epressive episodes at the other. There was a direct relationship betwe en the severity of depression over the longitudinal course and both du ration and recurrence of depressive episodes. The subgroup of depressi on with recurrence of both brief and longer duration episodes could be discriminated on most of the indicators of validity including symptom s, impairment, family history, and suicide attempts. In light of the y oung age of this cohort, the strong history of suicide attempts and ot her complications of depression among the subjects with recurrent depr ession was striking. These findings underscore the importance of emplo ying course as a classification criterion of depression, and the inclu sion of subthreshold episodes of depression in the characterisation of course.