The evolving understanding of major depression epidemiology: implications for practice and policy.

<bold>Objectives: </bold>Epidemiologic studies have confirmed that major depression (MD) is an extremely common condition, but also one that is associated with an unexpectedly broad spectrum of morbidity. It is no longer a tenable position to regard MD as being a simple indicator of treatment need, nor is a one-size-fits-all approach to treatment likely to be an effective guide to health care delivery. The objective of this commentary is to explore the implications of these new epidemiologic findings for policy and practice in Canada.<bold>Method: </bold>This paper is a selective review and commentary.<bold>Results: </bold>Whereas the acute and long-term treatment needs of a subset of individuals with MD have received much attention in the literature, the needs of other groups have not. A sizable proportion of individuals with episodes meeting the Diagnostic and Statistical Manual of Mental Disorders-fourth edition definition in community populations may not need the intensive treatment emphasized by current Canadian practice guidelines. The strategy of watchful waiting may have a role in primary care. On the policy front, guided and perhaps self-guided management strategies deserve greater emphasis than they have received. Stepped-care strategies are an appealing option, but how best to effectively implement these in the Canadian context is unclear.<bold>Conclusions: </bold>The spectrum of morbidity among individuals with MD in community populations is much wider than has been previously appreciated. The health system should respond with an appropriate spectrum of services, but many questions remain about how to facilitate this. [ABSTRACT FROM AUTHOR]