BACKGROUND: Seasonal rhythms in mood and behavior (seasonality) have been reported to occur in the general population. Seasonal affective disorder, a clinically diagnosed syndrome, is believed to represent the morbid extreme of a spectrum of seasonality. Two types of seasonality have been clinically described: one characterized by a winter pattern and a second by a summer pattern of depressive mood disturbance. METHODS: By using methods of univariate and multivariate genetic analysis, we examined the relative contribution of genetic and environmental factors to the risk of seasonality symptoms that were assessed by a mailed questionnaire of 4639 adult twins from a volunteer-based registry in Australia. RESULTS: Seasonality was associated with a winter rather than a summer pattern of mood and behavioral change. In each behavioral domain (ie, mood, energy, social activity, sleep, appetite, and weight), a significant genetic influence on the reporting of seasonal changes was found. Consistent with the hypothesis of a seasonal syndrome, genetic effects were found to exert a global influence across all behavioral changes, accounting for at least 29% of the variance in seasonality in men and women. CONCLUSIONS: There is a tendency for seasonal changes in mood and behavior to run in families, especially seasonality of the winter type, and this is largely due to a biological predisposition. These findings support continuing efforts to understand the role of seasonality in the development of mood disorders.
BACKGROUND: Seasonal rhythms in mood and behavior (seasonality) have been reported to occur in the general population. Seasonal affective disorder, a clinically diagnosed syndrome, is believed to represent the morbid extreme of a spectrum of seasonality. Two types of seasonality have been clinically described: one characterized by a winter pattern and a second by a summer pattern of depressive mood disturbance. METHODS: By using methods of univariate and multivariate genetic analysis, we examined the relative contribution of genetic and environmental factors to the risk of seasonality symptoms that were assessed by a mailed questionnaire of 4639 adult twins from a volunteer-based registry in Australia. RESULTS: Seasonality was associated with a winter rather than a summer pattern of mood and behavioral change. In each behavioral domain (ie, mood, energy, social activity, sleep, appetite, and weight), a significant genetic influence on the reporting of seasonal changes was found. Consistent with the hypothesis of a seasonal syndrome, genetic effects were found to exert a global influence across all behavioral changes, accounting for at least 29% of the variance in seasonality in men and women. CONCLUSIONS: There is a tendency for seasonal changes in mood and behavior to run in families, especially seasonality of the winter type, and this is largely due to a biological predisposition. These findings support continuing efforts to understand the role of seasonality in the development of mood disorders.
Authors: Kathryn A Roecklein; Kelly J Rohan; Wallace C Duncan; Mark D Rollag; Norman E Rosenthal; Robert H Lipsky; Ignacio Provencio Journal: J Affect Disord Date: 2008-09-18 Impact factor: 4.839
Authors: Enda M Byrne; Uttam K Raheja; Sarah H Stephens; Andrew C Heath; Pamela A F Madden; Dipika Vaswani; Gagan V Nijjar; Kathleen A Ryan; Hassaan Youssufi; Philip R Gehrman; Alan R Shuldiner; Nicholas G Martin; Grant W Montgomery; Naomi R Wray; Elliot C Nelson; Braxton D Mitchell; Teodor T Postolache Journal: J Clin Psychiatry Date: 2015-02 Impact factor: 4.384
Authors: Uttam K Raheja; Sarah H Stephens; Braxton D Mitchell; Kelly J Rohan; Dipika Vaswani; Theodora G Balis; Gagan V Nijjar; Aamar Sleemi; Toni I Pollin; Kathleen Ryan; Gloria M Reeves; Nancy Weitzel; Mary Morrissey; Hassaan Yousufi; Patricia Langenberg; Alan R Shuldiner; Teodor T Postolache Journal: J Affect Disord Date: 2012-11-17 Impact factor: 4.839