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Depression Research and Treatment
Volume 2011, Article ID 543906, 10 pages
http://dx.doi.org/10.1155/2011/543906
Research Article

Improvement in Fatigue, Sleepiness, and Health-Related Quality of Life with Bright Light Treatment in Persons with Seasonal Affective Disorder and Subsyndromal SAD

1Department of Neuroscience, Uppsala University, 75124 Uppsala, Sweden
2Center for Clinical Research Dalarna (CKF), Nissers väg 3, 791 82 Falun, Sweden
3Sleep Lab, Inland Hospital, 2500 Tynset, Norway
4Department of Psychology, Uppsala University, 752 37 Uppsala, Sweden

Received 17 January 2011; Revised 14 March 2011; Accepted 15 March 2011

Academic Editor: Wai Kwong Tang

Copyright © 2011 Cecilia Rastad 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.

Abstract

Objective. To investigate the effects of bright light treatment for secondary outcome measures and to explore and validate empirically derived subgroups and treatment effects in subgroups. Methods. A descriptive design. A sample of forty-nine persons (mean age of 45.8) with clinically assessed seasonal affective disorder (SAD) or subsyndromal SAD (S-SAD) participated in a two-group clinical trial evaluating the effects of treatment with bright light therapy. A person-oriented cluster analysis was applied to study treatment effects in subgroups. Results. For the merged group, sleepiness (Epworth Sleepiness Scale), fatigue (fatigue questionnaire), and health-related quality of life (SF-36) were improved at posttreatment, and results were maintained at the one-month followup. Three distinct subgroups had a high level of fatigue in common, while the level of excessive daytime sleepiness and depressed mood differed between the subgroups. Over time, all subgroups improved following ten days treatment in a light room. Conclusion. Fatigue, excessive daytime sleepiness, and health-related quality of life improve in a similar way as depressed mood following treatment with bright light. The treatment was effective irrespective of the severity of the disorder, that is, for persons with SAD and subsyndromal SAD.