Seasonal Affective Disorder, Social Support and Negative Life Events: A Test for an Evolutionary Psychological Explanation of Winter Depression

Pylkova Lyudmila, Department of Psychology, Novosibirsk State University, Russia

Background: Seasonal affective disorder (SAD) is now a well-described form of depressive disorder. The physical environment and biological factors are suggested to be the main causes of SAD. Due to that relatively little research has focused upon psychosocial factors as the possible predictors of SAD. In fact, only one unpublished research (made by Erin E. Michalak from Division of Mood Disorders, Department of Psychiatry, University of British Columbia, Canada) was aimed on testing the contribution of psychosocial risk factors in SAD. Meanwhile, an evolutionary psychological explanation of SAD (Putilov, 2002) predicts that, in particular, psychosocial factors would play much more important role in the development of SAD than would be assumed on the basis of the earlier suggested biological hypotheses, and that this role would be of a similar rank to that in development of other (non-seasonal) forms of depression.

Aim: To test psychosocial risk factors that are implicated in SAD cases in Novosibirsk (West Siberia, Russia, 55 degree North).

Method: Two questionnaires are used in the Michalak study were translated in Russian and applied to determine the association between psychosocial risk factors and SAD (see Appendix). 30 women aged between 22 and 63 were selected for the questionnaire study from a sample of patients who earlier were diagnosed as SAD (1988-2002) and participated in the researches of Dr. K. Danilenko. Age-matched sample of 30 asymptomatic women served as a control group.

Results: Low levels of social support were found to be the main factor contributed to development of SAD symptoms and seasonality. In particular, the significant differences between patients and controls were noted for the items related to tangible support: (p = 0.027), affectionate support and positive social interaction (p < 0.01 for both). However, there was no significant association between SAD and negative life events.

Discussion: Although the negative life events were not reported more often in SAD compared to controls, they would happen in life of our patients much earlier than now (the questionnaire is asking about the period of no longer than the last half of the year). In other respects our research results are similar to that of Michalak. Experience of low social support was found to be a good predictor of high seasonality and SAD diagnosis. This finding fits well in the evolutionary psychological hypothesis of SAD.

Conclusion: A new and unexpected by earlier theories of SAD association has been recently identified between seasonal depression and social support. The study finding suggested the necessity of future research is necessary for better understanding and explanation of the importance of psychosocial factors in seasonally manifesting forms of affective illnesses.