Sleep profile in hypomania: a polysomnographic evaluation in an egyptian sample

Abstract

Introduction Patients with major depression have been previously described to show a unique sleep profile, especially regarding REM sleep latency and density; however, the specificity of such changes is still a matter of debate. Studies concerning bipolar disorder are rather scarce and it is not well known whether it shares the same polysomnographic changes with major depression or not. The aim of the present study was to assess the polysomnographic features of patients with hypomania, compared to patients with unipolar depression. Materials and methods The study included 20 patients fulfilling the DSM-IV criteria of hypomania, compared to 20 patients, diagnosed by the same criteria as major depression. Patients were selected from those attending the outpatient clinic of the Institute of Psychiatry, Ain Shams University, Cairo, Egypt, with the age range between 18 and 45 years. the selected patients should be free from any psychotropic medication at least one week before the assessment and should not have any other psychiatric or major physical disorder. A control group of 20 healthy age and sex matched volunteers has been considered. All the study subjects were evaluated through complete physical and mental examination,Standardized Sleep Questionnaire (in Arabic), SCID-I for psychiatric diagnosis, based on DSM-IV criteria (for all patients), YMRS ( for hypomanic patients), HAMD (for major depression patients), and all-night polysomnography (for all subjects). Results Both hypomanic and depressed patients showed significant differences from controls, regarding decreased sleep efficiency, increased stages I and II, with decreased SWS. Short REML, with increased REMD have been also found in both groups of patients. Patients with hypomania differed significantly from those with depression in having more sleep efficiency, more SWS and less REM percentage.The changes in REML and REMD were more robust in depressed patients than in hypomania. Conclusion Sleep EEG findings in hypomania show some similarities to major depression, especially regarding the REM parameters, denoting common biological factors in both conditions.The quantitative difference in sleep efficiency and SWS, being higher in hypomania, might explain the rather ”refreshing” nature of sleep in hypomanic patients, compared to depression. Acknowledgements The authors would like to acknowledge Dr.Adel Marey, the sleep specialist in the Institute of Psychiatry, Ain Shams University, Cairo, Egypt, for his great support in sleep analysis of the studied sample.