SELF-REPORTED MENTAL DISTRESS UNDER THE SHIFTING DAYLIGHT IN THE HIGHNORTH

Background. The validity of the concept of seasonal affective disorder and the causal link to lack of daylight in winter is controversial. T here is a need for investigations in large samples of the general popu lation at different latitudes and within general research contexts to avoid selective response bias and sensitization of the population. Met hods. During a study of health effects of the air pollution from Russi a in a small community at 70 degrees north, a self-administered questi onnaire was filled in by 3736 inhabitants, 60.8% of the total populati on between 18 and 69 years. Three questions concerned depression, slee ping problems and other problems related to the two contrasting season s with regard to daylight. Results. Twenty-seven per cent reported to have some kind of problem in the dark period. Most frequently reported were sleeping problems during winter, in 19.9% of women and 11.2% of men. Self-reported depression in winter was found in 11.1% of women an d 4.8% % of men. Sleeping problems increased with age, while depressio n was most often reported by middle-aged people. The only other report ed problem in winter was fatigue. The adjusted relative risk (RR) for winter depression in women compared to men was 2.5 (95% confidence int erval: 1.9-3.2). Very few had problems in summer. Conclusions. In the high north, one-third of the women and one-fifth of the men experience problems with sleep, mood or energy related to season. The prevalence of self-reported depression was surprisingly low in winter considerin g the lack of daylight.