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High prevalence of self-reported winter depression in a Swedish county
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences.
2005 (English)In: Psychiatry and Clinical Neurosciences, ISSN 1323-1316, Vol. 59, no 6, 666-675 p.Article in journal (Refereed) Published
Abstract [en]

The prevalence of winter depression was unknown in Sweden, therefore prevalence figures of seasonal affective disorder (SAD) and subsyndromal SAD (S-SAD) were estimated. Age and gender differences, prevalence in the group of non-responders and some psychometric qualities of the Seasonal Pattern Assessment Questionnaire (SPAQ) were calculated. A modified version of the SPAQ was sent to a random sample of 2500 persons (response rate 66.3%, n=1657) between 18 and 64 years residing in Dalarna, a county in central Sweden. The sample was proportionally stratified according to age, gender and home municipality. The prevalence of winter SAD was estimated at 8% and S-SAD at 10.8%. It was approximately twice as common among women and younger persons. A total of 3.1% reported seasonal problems to be severe or disabling and 19.3% that everyday life was negatively affected. Experiencing seasonally changing depressive symptoms was common in the population. Factor analysis of the Global Seasonal Score resulted in one factor and the internal consistency was 0.88 (Cronbach's alpha). The results indicate that self-reported recurrent depression during winter is common in Sweden and should therefore receive more attention from health care authorities.

Place, publisher, year, edition, pages
2005. Vol. 59, no 6, 666-675 p.
Keyword [en]
factor analysis, internal consistency, prevalence, seasonal affective disorder, Seasonal Pattern Assessment Questionnaire
National Category
Medical and Health Sciences
URN: urn:nbn:se:uu:diva-98087DOI: 10.1111/j.1440-1819.2005.01435.xPubMedID: 16401242OAI: oai:DiVA.org:uu-98087DiVA: diva2:173266
Available from: 2009-02-10 Created: 2009-02-10 Last updated: 2009-09-29Bibliographically approved
In thesis
1. Winter Fatigue and Winter Depression: Prevalence and Treatment with Bright Light
Open this publication in new window or tab >>Winter Fatigue and Winter Depression: Prevalence and Treatment with Bright Light
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The aim of this thesis is to study prevalence of winter depressive mood and treatment effects of bright light for persons with winter fatigue and winter depression.

Study I is a cross-sectional survey of a random sample (N=1657) from the general population between 18-65 years of age in Dalarna, Sweden (latitude 60°N). Study II is a similar survey of 17-18 year old students (N=756) in the municipality of Falun. Approximately 20% of both samples report seasonal symptoms, mainly fatigue, lowered mood and increased sleep duration, appetite and weight.

Study III examines the effects of treatment in light rooms for persons from the sample in Study I (40 women, 10 men) with clinically assessed Seasonal Affective Disorder (SAD) or subclinical SAD (S-SAD). Subjects were randomised either to an experimental group receiving ten days of bright light treatment or to a three-week waiting-list control condition followed by bright light treatment. There was a >50% reduction of depressed mood in 13 of the 24 subjects in the experimental group, while none of the 24 controls reported a similar reduction. At the one-month follow-up, results were maintained and 39 of 47 subjects were improved >50%. Fatigue and excessive daytime sleepiness, which were high at baseline, were normal/below population norms for 39 of 47 subjects at the one-month follow-up. Mean values for the mental health aspect of health-related quality of life, which were low at baseline, improved and were close to norms at the one-month follow-up.

Study IV is a person-oriented subgroup/cluster analysis of the subjects in Study III. A common trait in all three clusters was a high level of fatigue hence the denomination ´Winter Fatigue´ is used for the merged group. Even though the degree of depressive mood and daytime sleepiness differed between the subgroups, all three groups improved following bright light treatment.

The results suggest that an increase in fatigue and depressed mood during the winter season is common in the general population. Bright light treatment reduces depressive mood, fatigue and excessive daytime sleepiness and improves health-related quality of life in persons with winter fatigue and winter depression.

Place, publisher, year, edition, pages
Uppsala: Universitetsbiblioteket, 2009. 77 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 421
National Category
urn:nbn:se:uu:diva-9561 (URN)978-91-554-7418-8 (ISBN)
Public defence
2009-03-19, Auditorium Minus, Gustavianum, Akademigatan 3, Uppsala, 13:15 (Swedish)
Available from: 2009-02-26 Created: 2009-02-10 Last updated: 2009-03-12Bibliographically approved

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