Seasonal variations in eating disorder subtypes in Japan

Abstract

Objective: This study estimated the degree of seasonal changes in eating disorder subtypes in Japan.

Method: A Japanese version of the Seasonal Pattern Assessment Questionnaire (SPAQ) was mailed to 228 outpatients with eating disorders in Kyoto (latitude 35 degrees 01' N). Ninety responses were analyzed. The mean of the global seasonality score (GSS) in the SPAQ and the comorbidity rate of seasonal affective disorder (SAD) and subsyndromal-SAD in each subtype were used as indices of seasonality.

Results: The mean (8.2) of the GSS of the bulimia nervosa (BN) group and the sum (43%) of the comorbidity rates of SAD and subsyndromal-SAD in the BN group were significantly higher than those in the nonclinical comparison group.

Discussion: The seasonality of BN in Kyoto is the highest among eating disorder subtypes, although lower than that in North America. This finding suggests that light therapy could be useful for Japanese BN patients.