To test the hypothesis that depression and REM sleep share common
cholinergic mechanisms the authors administered arecoline 25 min after
completion of the first REM period to 14 patients with remitted bipolar
affective disorder, 15 normal controls, and 5 subjects with a personal or
family history of affective disorder. The second REM period occurred
significantly sooner in the remitted patients than in the normal controls.
The patients also had a significantly higher density of eye movements
during the first REM period and a higher percentage of REM sleep. The
authors believe that increased cholinergic sensitivity and REM density may
be biological markers of increased vulnerability to bipolar affective
illness.Abstract Teaser