WASHINGTON, DC— A variation in sleep duration of more than three hours may indicate that a large mood change is imminent, generally occurring the next day, in patients with bipolar disorder, according to research reported at the 161st Annual Meeting of the American Psychiatric Association. Michael Bauer, MD, PhD, and colleagues said that sleep duration is a more useful parameter for patients to monitor their oncoming mood changes than sleep onset or sleep offset.

Dr. Bauer, Professor of Psychiatry and Director and Chairman of the Department of Psychiatry and Psychotherapy, University Hospital Carl Gustav Carus, Technische UniversitŠt Dresden, Germany, and colleagues based their findings on 101 outpatients with bipolar disorder (mean age, 37.7; 67 females). Dr. BauerÕs group found a significant negative cross-correlation between a change in sleep duration and a change in mood in 42 patients (42%) for the day before or the day of the mood change, with 39% of cases occurring on the day before. Sleep loss was followed by a shift in mood toward hypomania/mania on the next day, and a sleep gain was followed by a shift in mood toward depression on the subsequent day, according to the investigators.

Patients who had a significant cross-correlation between sleep duration and mood included 86% of those with a significant cross-correlation between sleep onset or offset and mood. About 12.5% of daily sleep changes were greater than three hours, and 6.4% of daily mood changes were greater than 20 points in either direction on a 100-unit visual self-rating scale. Also, patients who had a significant correlation reported 65.6% of all sleep changes to be more than three hours and 83.1% of all mood changes to be greater than 20 points.

ÒThere is considerable individual variability in the impact of sleep changes in relation to mood,Ó Dr. Bauer told NeuroPsychiatry Reviews. ÒHowever, the patients with a significant cross-correlation between sleep and mood experienced more mood symptomsÑsuch as depression, mania, and large mood changesÑand more sleep symptoms, such as large sleep changes, and had large changes from mean euthymic sleep duration while depressed or manic. Patients who are vulnerable to the impact of sleep changes on mood should closely monitor sleep duration on an ongoing basis. These patients should be educated on the importance of regular sleep habits and be taught that changes in sleep duration of greater than three hours may signify an imminent mood change and/or the need to obtain professional help.Ó

—Colby Stong

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