Seasonality of symptoms in anorexia and bulimia nervosa.

OBJECTIVE: Recent research has suggested that a large proportion of patients with bulimia nervosa have seasonal (winter) worsening of mood symptoms similar to seasonal affective disorder (SAD). The objectives of this study were to determine the specificity of this finding in anorexia and bulimia nervosa, and to further delineate the seasonal mood and eating patterns in bulimia nervosa.

METHOD: A modified Seasonal Pattern Assessment Questionnaire (SPAQ) was administered to consecutive female patients assessed at an Eating Disorders Clinic with DSM-III-R diagnoses of bulimia nervosa (BN, N = 60) and anorexia nervosa (AN, N = 31), and to female nonclinical comparison subjects (NC, N = 50).

RESULTS: The BN group had higher global seasonality scores and more presumptive diagnoses of SAD than the other two groups; the AN patients, whether they had the restricting or binge eating/purging subtype, did not differ from the NC subjects. Thirty-two percent of the identified seasonal BN patients did not have parallel worsening of mood and eating symptoms in the same season.

DISCUSSION: These results suggest that seasonality of symptoms is specific to BN and that there may be separate mechanisms for the seasonality of mood and eating symptoms in some BN patients.