Does obstructive sleep apnea confound sleep architecture findings in subjects with depressive symptoms?
GROUND: Compared with normal subjects, depressed patients have shorter rapid eye movement sleep latency (REML), increased REM and decreased slow wave sleep as a percentage of total sleep time (REM%, SWS%), and longer sleep latency (SL). Obstructive sleep apnea (OSA) patients experience longer REML, decreased REM% and SWS%, and shorter SL. We examined the interplay of depressive symptoms, OSA, and sleep architecture. METHODS: Subjects (n = 106) were studied with polysomnography. OSA was defined as a Respiratory Disturbance Index > or = 15. Subjects were divided into Hi/Lo groups using a Center for Epidemiological Studies-Depression (CES-D) score of 16. RESULTS: OSA patients had shorter SL than non-OSA patients (14.5 vs. 26.8 min, p <.001); Hi CES-D subjects showed a trend toward longer SL than Lo CES-D subjects (23.7 vs. 17.5 min, p =.079). Significant OSA x CES-D interactions emerged, however, for REM% (p =.040) and SL (p =.002): OSA/Hi CES-D subjects had higher REM% than OSA/Lo CES-D
