Major Depression in Canada: What Has Changed over the Past 10 Years?

Major depressive episodes (MDE) make an important contribution to disease burden in Canada. The epidemiology of MDE in the national population has been examined in 2 mental health surveys, one conducted in 2002 and the other in 2012. Our objective was to compare selected variables from the 2 surveys to determine whether changes have occurred in the prevalence, treatment, and impact of MDE.

The World Health Organization World Mental Health Composite International Diagnostic Interview was used in both surveys and the MDE module (which was not modified) was scored using the same algorithm. Some variables assessing impact and management of MDE were also identical in the 2 surveys. The analysis was based on frequency estimates and associated 95% confidence intervals.

The annual prevalence of MDE was 4.7% (95% CI 4.3% to 5.1%) in 2012, nearly identical to 4.8% (95% CI 4.5% to 5.1%) in 2002. Receipt of potentially adequate treatment (defined as taking an antidepressant or 6 or more visits to a health professional for mental health reasons) increased from 41.3% in 2002 to 52.2% in 2012, mostly due to an increase in respondents reporting 6 or more visits. Use of second generation antipsychotics also increased. There was no evidence of diminishing prevalence or impact (as assessed by symptoms of distress).

There appears to have been an increase in receipt of treatment for people with MDE and a changing pattern of management. However, it was not possible to confirm that the impact of MDE is diminishing as a result.