Sleep of atypical depressives.

Patients who met provincial criteria for atypical depression were contrasted with a group of patients who met RDC criteria for endogenous depression and a group of normal controls on a standard series of sleep variables. Atypical depressives were differentiated from normal controls by a shortened REMP latency. They did not, however, appear to have the sleep continuity disturbance exhibited by endogenous depressives. This preliminary work suggests that atypical depressives may have a unique pattern of sleep variables consisting of REM abnormalities without continuity disturbance. If this pattern is observed in additional studies, it would add to the validity of considering atypical depression a subtype of unipolar depressive illness.