Activity Level, Activity Enjoyment, and Weather as Mediators of Physical Health Risks in Seasonal and Nonseasonal Depression

Research suggests that depression has negative consequences on physical health. One of the mechanisms driving this link may be the decrease in physical activity characteristic of individuals before and during a depressive episode. However, the factors that influence changes in physical activity across the seasons remain unclear. For instance, weather has been proposed to play an important role in the frequency of activities and enjoyment derived from them. In addition, research has not investigated how weather variables influence activity levels across the seasons in individuals with seasonal versus nonseasonal depression. The present study compared patterns of activity level and enjoyment in samples of women with seasonal and nonseasonal depression and controls. Women with Major Depressive Disorder (MDD) and MDD with a seasonal pattern (Seasonal Affective Disorder, SAD) reported similar patterns of activity; engaging in less frequent activity and deriving less enjoyment from activities than controls across the entire year, most notably during the winter months. Women with SAD also reported being significantly impacted by the weather such that their mood and energy levels increased with warmer temperatures an increased sunshine. Results suggest that women with seasonal depression may be at similar health risks as women with nonseasonal depression and activity patterns may have implications for behavioral activation treatments for depression.