Descriptive epidemiology of major depression in Canada

The Canadian Community Health Survey: Mental Health and Well-Being (CCHS 1.2) is the first national study to use a full version of the Composite International Diagnostic Interview. For this reason, and because of its large sample size, the CCHS 1.2 is capable of providing the best currently available description of major depression epidemiology in Canada. Using the CCHS 1.2 data, our study aimed to describe the epidemiology of major depression in Canada.

All estimates used appropriate sampling weights and bootstrap variance estimation procedures. The analysis consisted of estimating proportions supplemented by logistic regression modelling.

The lifetime prevalence of major depressive episode was 12.2%. Past-year episodes were reported by 4.8% of the sample; 1.8% reported an episode in the past 30 days. As expected, major depression was more common in women than in men, but the difference became smaller with advancing age. The peak annual prevalence occurred in the group aged 15 to 25 years. The prevalence of major depression was not related to level of education but was related to having a chronic medical condition, to unemployment, and to income. Married people had the lowest prevalence, but the effect of marital status changed with age. Logistic regression analysis suggested that the annual prevalence may increase with age in men who never married.

The prevalence of major depression in the CCHS 1.2 was slightly lower than that reported in the US and comparable to pan-European estimates. The pattern of association with demographic and clinical variables, however, is broadly similar. An increasing prevalence with age in single (never-married) men was an unexpected finding.