Delusional and non-delusional depression in late life. Evidence for distinct subtypes

The study tests the hypothesis that delusional and non-delusional depressive illnesses are distinct entities in late life. Two groups of 24 patients with late-onset depression, one with and one without delusions, were compared retrospectively. At the index admission, deluded patients were significantly more depressed, were in hospital for longer, responded poorly to antidepressants alone and required more physical treatments, especially ECT and major tranquillisers. Although illness severity was a major factor accounting for these differences, the finding that only the deluded group experienced delusional relapses suggests an underlying intrinsic susceptibility. The discharge status was similar for both groups, as were relapse rates over 48 months and the clinical course of depressive symptoms over 42-104 months. The findings are consistent with studies of younger patients which point to a distinction between these two types of depression, but not with recent work suggesting a very poor prognosis for delusional depression in late life.