Diagnosis of depression in people with severe/profound intellectual disability.

The Marston 30 Symptoms Checklist for detecting depression was used to determine whether or not the notion of 'depressive equivalents' can provide a few of the core characteristics necessary for the diagnosis of depressive disorders in people with severe/profound intellectual disability (ID). Diagnoses of major depression were made by a psychiatrist using the DSM-III-R criteria, combined with information from records, staff, team, parents, behaviour profiles, direct observations, mental status and follow-up visits. Twenty-two people with ID fulfilled the selection criteria from a larger sample of 150 patients who had been evaluated in 350 contact visits. Scores on the checklist for major depression for 15 subjects with severe/profound ID were similar to the core characteristics for diagnosis of major depression by DSM-III-R criteria. Evidence was found for the presence of depressive equivalents in the subjects, but these appeared to be secondary. The 15 participants with severe/profound ID were observed mostly during the depressive phase of bipolar I and bipolar II disorder, and major depression, recurrent type. Melancholic features were prominent in their presentation. Further studies of people with ID are needed to determine whether depressive equivalents are more prominent in cases of major depression with atypical features than in cases of major depression with melancholic features.