Is mental health in the Canadian population changing over time?

OBJECTIVE: Mental health in populations may be deteriorating, or it may be improving, but there is little direct evidence to support either possibility. Our objective was to examine secular trends in mental health indicators from national data sources.
METHODS: We used data (1994-2008) from the National Population Health Survey and from a series of cross-sectional studies (Canadian Community Health Survey) conducted in 2001, 2003, 2005, and 2007. We calculated population-weighted proportions and also generated sex-specific, age-standardized estimates of major depressive episode prevalence, distress, professionally diagnosed mood disorders, antidepressant use, self-rated perceived mental health, and self-rated stress.
RESULTS: Major depression prevalence did not change over time. No changes in the frequency of severe distress were seen. However, there were increases in reported diagnoses of mood disorders and an increasing proportion of the population reported that they were taking antidepressants. The proportion of the population reporting that their life was extremely stressful decreased, but the proportion reporting poor mental health did not change.
CONCLUSIONS: Measures based on assessment of symptoms showed no evidence of change over time. However, the frequency of diagnosis and treatment appears to be increasing and perceptions of extreme stress are decreasing. These changes probably reflect changes in diagnostic practice, mental health literacy, or willingness to report mental health concerns. However, no direct evidence of changing mental health status was found.