MAJOR DEPRESSION, MINOR DEPRESSION, AND DOUBLE DEPRESSION - ARE THEY DISTINCT CLINICAL ENTITIES

The clinical concept of ''double depression,'' i.e., the superimpositi on of a major depressive disorder in a patient with dysthymic disorder , implies that there are at least some differences between dysthymia, major depression, and double depression, However. the relationship bet ween these two syndromes remains unclear, The present study uses genet ic methodology to explore any possible relationship between minor depr ession, double depression, and major depression, From 1988-1990, all c onsecutive unrelated inpatients and outpatients (index cases) presenti ng to a university-based mood disorders service had detailed family hi stories taken, using modification of the ''family history method.'' Di agnoses for index cases and their first-degree relatives were made acc ording to Research Diagnostic Criteria, For all index cases with a dia gnosis of minor or intermittent depression, and minor/intermittent dep ression plus either single or recurrent depression (''double depressio n''), morbidity risks for mood disorders were calculated for first-deg ree relatives (parents, siblings, and children) using the maximum like lihood approach, Results showed no significant differences in morbidit y risk calculations to first-degree relatives of index cases with mino r/intermittent depression, major depression, or double depression, The data from this genetic perspective suggest that single depression, re current depression, minor depression, and double depression are indist inguishable. (C) 1996 Wiley-Liss, Inc.