The seasonality of bipolar affective disorder: Comparison with a primary care sample using the Seasonal Pattern Assessment Questionnaire

BackgroundIn contrast with recurrent unipolar depression, relatively little is known about the seasonality of depressive episodes in bipolar affective disorder (BAD).MethodWe compared responses on the Seasonal Pattern Assessment Questionnaire (SPAQ) between a cohort of 183 patients with BAD and a large sample of patients in primary care (N = 4746). Comparisons were adjusted for age and gender.Results27% of the BAD patients fulfilled SPAQ criteria for Seasonal Affective Disorder (SAD. This gave an adjusted odds ratio of 3.73 (95% confidence intervals 2.64 to 5.27) in comparison with the rate among the primary care samples. Global seasonality scores were significantly higher among BAD patients (adjusted mean difference 1.73, 95% CI 0.97 to 2.49, p < 0.001).LimitationsThe SPAQ was originally designed as a screening instrument rather than as a case-finding instrument.ConclusionsVigilance for seasonal symptom recurrence in BAD may be important with regard to management and relapse prevention.