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…
Contents
Introduction
The clinical picture
Seasonal Affective Disorder (SAD)
Subclinical SAD (S-SAD)
Symptoms described by the patients
Prevalence
Possible etiological factors
The biomedical perspective
The biopsychosocial perspective
Fatigue and excessive daytime sleepiness
Light and how it is measured
Bright light therapy
Light intensity, duration and timing of treatment
Two different settings; light boxes and light rooms
Side effects and risks
Clinical studies
Intentions and scope of the present thesis
Aims
Methods
Subjects, procedure and design
Study I
Study II
Study III and IV
Measures
Seasonal symptoms
Pretreatment expectations
Depressed mood
Fatigue
Daytime sleepiness
Health-related quality of life
Data analyses
Study I and II
Study III
Study IV
Results
Prevalence
The adult sample (Study I)
The adolescent sample (Study II)
Treatment effects
Depressed mood (Study III)
Fatigue, sleepiness and health-related quality of life (Study IV)
Exploring subgroups and treatment effects
Clusters (Study IV)
Validation of clusters and treatment effects (Study IV)
Discussion
General discussion
Prevalence
Treatment effects
Methodological considerations
Internal and construct validity
External validity
Clinical implications and future research
Summary and conclusions
Acknowledgements
References
Author: Rastad, Cecilia
Source: Uppsala University Library
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