Am J Psychiatry 1991; 148:1177-1181
Copyright © 1991 by American Psychiatric Association
Hypersomnia in bipolar depression: a comparison with narcolepsy using the multiple sleep latency test
EA Nofzinger, ME Thase, CF Reynolds 3d, JM Himmelhoch, A Mallinger, P Houck and DJ Kupfer
Department of Psychiatry, University of Pittsburgh School of Medicine, PA.
OBJECTIVE: This study characterized objectively the hypersomnia frequently
seen in the depressed phase of bipolar affective disorder. On the basis of
previous work in sleep and affective disorders, it has been hypothesized
that the hypersomnia is related to greater REM sleep. This hypothesis was
tested by using a multiple sleep latency test to compare bipolar affective
disorder with narcolepsy, a well-defined primary sleep disorder associated
with known REM sleep dysfunction. METHOD: Twenty-five bipolar depressed
patients were selected on the basis of complaints of hypersomnia. They
underwent 2 nights of polysomnography followed by a multiple sleep latency
test. Data on their nocturnal sleep and daytime naps were compared with
similar data on 23 nondepressed narcoleptic patients referred for sleep
evaluation. RESULTS: Despite their complaints of hypersomnia, no
abnormalities were noted for the bipolar group in the results from the
multiple sleep latency test. Contrary to the working hypothesis, REM sleep
was notably absent during daytime naps in the depressed patients, in marked
contrast to the findings for the narcoleptic group. CONCLUSIONS: The
complaint of sleepiness in the hypersomnic bipolar depressed patient
appears to be related to the lack of interest, withdrawal, decreased
energy, or psychomotor retardation inherent in the anergic depressed
condition, rather than an increase in true sleep propensity or REM sleep
propensity.
