On the basis of two EEG sleep criteria, REM latency and REM activity,
the authors achieved 81% accuracy in distinguishing between 47 patients
with primary depression and 48 patients with secondary depression using
discriminant analysis. Sleep efficiency, the percentage of delta sleep, and
the percentage of REM sleep discriminated between psychotic and
nonpsychotic subgroups in the group with primary depression with 75%
accuracy. REM activity and intermittent nocturnal awakening accurately
discriminated two subtypes of patients with secondary depression at a level
of 81%. These results suggest that EEG sleep measurements can yield
significant data to aid in differential diagnosis in psychiatry.Abstract Teaser