The relationship of EEG sleep to vital depression.

EEG sleep and clinical characteristics of 111 depressed inpatients with primary unipolar depression were examined in relation to several proposed definitions of endogenous depression (RDC criteria; DSM-III melancholia; and Nelson-Charney criteria). While each of these clinical schema demonstrated specific relationships to the EEG sleep findings in the overall group, the group with DSM-III melancholia showed definite REM sleep abnormalities, especially with REM activity and distribution. Further studies with sleep, neuroendocrine, and neurochemical measures are indicated in order to confirm the biologic 'substrate' of melancholia or vital depression.