Community survey of bipolar disorder in Canada: Lifetime prevalence and illness characteristics

Objective: This study reports on the lifetime prevalence and illness characteristics of bipolar disorder (BD) in a large, representative sample of Canadians. Method: Data were obtained from the Canadian Community Health Survey: Mental Health and Well-Being. This representative, cross-sectional survey, conducted by Statistics Canada in 2002, examines the mental health of Canadians aged 15 years and over. The national response rate was 77%. We determined the prevalence rate of BD, correlates of a bipolar diagnosis, and illness characteristics. Results: The weighted lifetime prevalence rate of BD was 2.2% (95% confidence interval [CI], 1.94% to 2.37%). Younger age, low income adequacy, lifetime anxiety disorder, and presence of a substance use disorder in the past 12 months were each significantly associated with the presence of a BD diagnosis (P < 0.001 for each). The largest effect found was for the presence of an anxiety disorder (odds ratio 7.94; 95% CI, 6.35 to 9.92). A lifetime history of anxiety disorder was reported by 51.8% (95% CI, 47.1% to 56.5%) of the respondents with BD, with both panic disorder and agoraphobia each being more frequent among women, compared with men (P = 0.01 and P < 0.001, respectively). The mean age at onset of illness was 22.5 years, SD 12.0. Conclusions: According to the estimated lifetime prevalence of BD found in this study, over 500 000 Canadians likely suffer from this condition. Identifying those at highest risk for BD may assist in developing more effective community-based identification and intervention strategies.