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Depression Research and Treatment
Volume 2012, Article ID 978962, 6 pages
Clinical Study

Seasonality and Sleep: A Clinical Study on Euthymic Mood Disorder Patients

Department of Neuropsychiatric Sciences, Scientific Institute, University Vita-Salute San Raffaele, 20127 Milan, Italy

Received 1 July 2011; Revised 27 September 2011; Accepted 17 October 2011

Academic Editor: Colom Francesc

Copyright © 2012 Chiara Brambilla et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Background. Research on mood disorders has progressively focused on the study of seasons and on the mood in association with them during depressive or manic episodes yet few studies have focused on the seasonal fluctuation that characterizes the patient's clinical course both during an illness episode and during euthymic periods. Methods. 113 euthymic outpatients 46 affected by major recurrent depression and 67 affected by bipolar disorder were recruited. We evaluated the impact of clinical “rhythmical” factors: seasonality, sleep disturbance, and chronotype. Patients completed the SPAQ + questionnaire, the MEQ questionnaire, and the medical outcomes study (MOS) sleep scale. We used t-test analyses to compare differences of clinical “rhythmical” and sociodemographic variables and of differences in the assessment scales among the diagnostic groups. Results. Patients reporting a family history for mood disorders have higher fluctuations throughout seasons. Sleep disturbance is more problematic in unipolars when compared to bipolars. Conclusions. Sleep, light, and seasonality seem to be three interconnected features that lie at the basis of chronobiology that, when altered, have an important effect both on the psychopathology and on the treatment of mood disorders.