Seasonal Shifts Impact Mood in All, but Research Participants with Bipolar Disorder Feel the Effects More Intensely, Study Finds

Bipolar disorder is known for causing extreme mood swings. A new study published in the Journal of Affective Disorders showcasing the multi-site collaborative Bipolar Research Sleep and Circadian Rhythms (BRSCr) and co-authored by University of Michigan Drs. Sperry, Burgess, Yocum and McInnis aimed to see how these mood changes might vary with the seasons over time. Researchers analyzed data from the Heinz C. Prechter Longitudinal Study of Bipolar Disorder and included individuals with both bipolar type I and II as well as a control group of healthy individuals.

Using data from the long-term study, they found that mood symptoms indeed change with the seasons. During months with less daylight (autumn), depressive symptoms were more common than in months with the most daylight (summer). In contrast, (hypo)mania symptoms were higher during seasons with longer daylight (spring and summer) compared to autumn and winter. This was true for all individuals, regardless of diagnosis. In contrast, when asked about the impact of season on mood via the Global Seasonality Score, individuals with bipolar disorder type I and II reported significantly greater seasonality than those without bipolar disorder. Furthermore, higher scores on this measure were associated with greater variability in mood symptoms. Taken together, individuals with bipolar disorder perceive strong seasonal impacts on mood but did not actually show stronger impacts of season on mood compared to those without bipolar disorder.

None-the-less, these findings highlight that season changes do have an impact on mood, and individuals with bipolar disorder perceive those season changes to significantly impact mood. As such, interventions focused on relapse prevention may benefit from adjusting strategies based on the season.  Overall, recognizing these seasonal patterns may lead to better management and more targeted interventions for individuals with bipolar disorder.

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