International differences in major depression prevalence: what do they mean?

The international literature concerned with major depression prevalence has been growing rapidly, providing a wealth of new information about prevalence in different countries. In understanding and using these rates, analytically oriented epidemiologists, decision makers, and administrators, however, need to be aware of a set of interpretive difficulties. Experience suggests that international major depression prevalence comparisons should be treated with caution. The portability of major depression diagnostic criteria across countries requires further confirmation, and existing diagnostic interviews have technical vulnerabilities that may render international comparisons vulnerable to measurement bias.