Abstract
INTRODUCTION: Few studies have investigated potential seasonal changes in anxiety disorders. This study aimed to evaluate whether seasonal changes influence the severity of obsessive and compulsive symptoms in obsessive-compulsive disorder (OCD). The relationship between comorbid anxiety and depression symptoms and the seasons was also investigated. Furthermore, we compared the differences between retrospective data reliant on patients' recall and data obtained by prospective observation. METHODS: The Yale-Brown Obsessive Compulsive Scale (Y-BOCS), Y-BOCS Symptom Checklist, Beck Anxiety Scale, and Beck Depression Scale were administered to 148 patients with OCD in each of the four seasons over a year. The relationships between the seasons and the scales based on retrospective observations of the patients, and between the seasons and scales based on prospective data collected over the year were analyzed. Scores from clinical assessments were compared between the different seasons. RESULTS: The severity of obsessive and compulsive symptoms, did not show seasonal changes. Multi-level growth models suggested that the change in Y-BOCS Total scores across seasons could be explained by subjective symptoms of depression and anxiety and their interactions. Importantly, results obtained using prospective observations from structured clinical assessment differed from those obtained using retrospective observations of patients. CONCLUSIONS: Our study does not support the existence of seasonal variations in symptoms of OCD. Future studies are needed to delineate seasonal variations in OCD symptoms.