The relationship between subjective sleep estimation and objective sleep variables in depressed patients

Introduction: To our knowledge there is no evidence in the literature about the relationship between subjective sleep estimation and objective sleep v ariables in depression. It is not known whether the subjective estimation o f sleep quality and sleep duration is directly related to any objective sle ep variable in depressed patients. Methods: Thirty patients with major depr ession and 10 healthy subjects have been investigated in our sleep laborato ry during 1 or 2 consecutive nights after 1 night for adaptation. Every sub ject, after final awakening in the laboratory, answered questions concernin g the subjective feelings about sleep duration, number of awakenings and sl eep depth. We compared the sleep estimation in both groups and calculated t he correlation between objective and subjective sleep variables in depresse d patients. Results: The degree of a wrong sleep estimation in depressed pa tients is larger than in healthy subjects. Slow wave sleep (SWS) in depress ed patients correlates positively with the subjective estimation of sleep d uration. Eye movement density in REM sleep correlates with the subjective e stimation of the number of awakenings. Conclusion: SWS in depression has a positive influence on the subjective feeling of sleep duration while phasic REM sleep activity has a negative influence. (C) 2000 Elsevier Science B.V . All rights reserved.