Proposed delusional depression subtypes: preliminary evidence from a retrospective study of phenomenology and treatment course.

An analysis of the phenomenology and treatment course of 52 subjects with delusional depression suggests that there may be various subtypes: bipolar, early-onset unipolar and possibly a late-onset unipolar. The bipolar subgroup tended to relapse in different but always psychotic directions, and was resistant to lithium carbonate treatment alone. Treatment refractoriness, delusional depressive recurrences, and a dementia-like presentation were associated with a small late-onset subgroup. A high rate of delusionally depressive relapses also characterized the early-onset unipolar group, however, patients with single episodes were found only in this subgroup.