Progress against major depression in Canada.

Abstract

BACKGROUND: Generally, public health strategies for major depression have focused on case-finding, public and professional education, and disease-management strategies. In principle, increased rates of treatment utilization and improved treatment outcomes should lead to improved mental health at the population level. Progress of this sort, however, has been difficult to confirm. METHODS: The National Population Health Survey (NPHS) is a large-scale longitudinal study of a representative sample drawn from the Canadian population. To date, Statistics Canada has released data from 3 NPHS cycles: 1994-1995, 1996-1997, and 1998-1999. Treatment utilization and major depression measures were employed in the NPHS survey, providing a unique source of longitudinal Canadian data. In this study, major depression point prevalence (defined using a predictive instrument for annual major depressive episode [MDE] prevalence and responses from a distress scale) and associated treatment utilization were evaluated over time. RESULTS: Between 1994-1995 and 1995-1996, the proportion of persons with depression receiving antidepressant treatment increased dramatically, from 18.2% (12.3% to 22.1%) in 1994-1995 to 32.6% (23.0% to 42.2%) in 1998-1999. Point prevalence of major depression was 2.4%, 1.8%, and 1.9% in the 3 NPHS iterations. CONCLUSIONS: Data from the NPHS suggest public health progress against major depression in Canada. More people with major depression in Canada are receiving treatment, and these changes may have been associated with improved population health status. However, both random variation and extraneous societal factors could account for the observed trends in prevalence. It is impossible to relate changes in utilization directly to population health status using the NPHS data.