Seasonality contributes to depressive, anxiety and alcohol use disorders in the Finnish general adult population.

Background: Earlier evidence suggests that the seasonal changes in mood and behavior are associated with mental disorders, especially with mood disorders. However, the extent of these associations has not been analyzed by using large samples of the general population.
Methods: A random sample of adults, aged 29 to 97 years and representative of the general population living in Finland, attended a nationwide health examination survey. Mental disorders were assessed with the Munich version of the Composite International Diagnostic Interview (M-CIDI, n = 4554). Of them, the seasonal variations in mood and behavior (seasonality) were assessed with the six items of the Global Seasonality Score (GSS, n = 4004) as well as with the experienced problem due to these variations.
Results: After adjusting for age, gender, level of education, and region of residence, the GSS was associated with depressive, anxiety and alcohol use disorders (all p < 0.001). Of the GSS items, mood was associated with depressive disorders (p < 0.001), anxiety disorders (p = 0.003) and alcohol use disorders (p = 0.008), whereas appetite was associated only with depressive disorders (p = 0.012), and energy level only with anxiety disorders (p = 0.025).
Limitations: This cross-sectional study was based on self-reported data on the seasonal pattern.
Conclusions: Seasonality had significant associations with depressive, anxiety and alcohol use disorders among the general adult population. This needs attention in clinical practice.
(Copyright © 2022. Published by Elsevier B.V.)