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Free keywords:
polysomnography; REM sleep; depression; vulnerability; high- risk subjects
Abstract:
Background: Some of the sleep abnormalities found in depression also persist in remission, suggesting that these parameters could represent trait or vulnerability markers. In a previous study, we found that about one third of a group of high-risk probands (HRPs) showed sleep patterns that were comparable to those of depressed patients. In the present study, we re- investigated a subsample of these HRPs to evaluate the stability of these findings over time. Methods: We investigated the sleep-electroencephalograms of 82 healthy subjects with a high genetic load of affective disorders. We were able to re- investigate 26 of these HRPs after a mean interval of 3.5 years. Thirty-five unrelated control probands and 33 unrelated depressed inpatients that were recruited at the first investigation served as reference groups. Results: At index investigation, we found that the HRPs showed a significantly increased rapid eye movement (REM) sleep density, compared to control subjects. At the second examination, no changes of the polysomnographic observations over time could be observed; in particular, the REM density remained elevated. Conclusions: The increased REM density in high-risk subjects for an affective disorder at index investigation was stable over time, so that one of the requirements for a true vulnerability marker is fulfille
