Seasonal changes in clinical status in bipolar disorder: a prospective study in 1000 STEP‐BD patients

Abstract

The prevalence of depression is greater in patients from the northern vs. southern STEP-BD sites. Seasonal peak prevalence rates of depression differ by region. Bipolar II patients were more ill year-round and demonstrated greater monthly fluctuation in prevalence rates of being ill than did bipolar I patients. We conclude that seasonal effects upon bipolar patients vary by region and bipolar subtype.