Canadian Network for Mood and Anxiety Treatments (CANMAT) clinical guidelines for the management of major depressive disorder in adults. I. Classification, burden and principles of management.

Background: Major depressive disorder (MDD) is one of the most burdensome illnesses in Canada. The purpose of this introductory section of the 2009 revised CANMAT guidelines is to provide definitions of the depressive disorders (with an emphasis on MDD), summarize Canadian data concerning their epidemiology and describe overarching principles of managing these conditions. This section on "Classification, Burden and Principles of Management" is one of 5 guideline articles in the 2009 CANMAT guidelines.

Methods: The CANMAT guidelines are based on a question-answer format to enhance accessibility to clinicians. An evidence-based format was used with updated systematic reviews of the literature and recommendations were graded according to the Level of Evidence using pre-defined criteria. Lines of Treatment were identified based on criteria that included evidence and expert clinical support.

Results: Epidemiologic data indicate that MDD afflicts 11% of Canadians at some time in their lives, and approximately 4% during any given year. MDD has a detrimental impact on overall health, role functioning and quality of life. Detection of MDD, accurate diagnosis and provision of evidence-based treatment are challenging tasks for both clinicians and for the health systems in which they work.

Limitations: Epidemiologic and clinical data cannot be seamlessly linked due to heterogeneity of syndromes within the population.

Conclusions: In the eight years since the last CANMAT Guidelines for Treatment of Depressive Disorders were published, progress has been made in understanding the epidemiology and treatment of these disorders. Evidence supporting specific therapeutic interventions is summarized and evaluated in subsequent sections.