Objective: To determine the prevalence of major depression in multiple sclerosis (MS) in a population-based sample controlling for nonspecific illness effects.
Methods: This study used data from a large-scale national survey conducted in Canada: the Canadian Community Health Survey (CCHS). The analysis included 115,071 CCHS subjects who were 18 years or older at the time of data collection. The CCHS interview obtained self-reported diagnoses of MS and employed a brief predictive interview for major depression: the Composite International Diagnostic Interview Short Form for Major Depression. The 12-month period prevalence of major depression was estimated in subjects with and without MS and with and without other long-term medical conditions.
Results: The prevalence of major depression was elevated in persons with MS relative to those without MS and those reporting other conditions. The association persisted after adjustment for age and sex (adjusted odds ratio = 2.3, 95% CI 1.6 to 3.3). Major depression prevalence in MS for those in the 18- to 45-year age range was high at 25.7% (95% CI 15.6 to 35.7).
Conclusions: The prevalence of major depression in the population with MS is elevated. This elevation is not an artifact of selection bias and exceeds that associated with having one or more other long-term conditions.