Wealthier Countries' Citizens Are More Likely Depressed

From Albania to Zanzibar, countries differ in many ways--in their history, culture, ethnic makeup, climate, and economic power, among others. Do countries also differ in their psychiatric health? In their propensity to mood disorders, anxiety disorders, or schizophrenia? This is a simple question, but one that is surprisingly challenging to answer. Good epidemiological studies of mental disorders are labor intensive, requiring many the use of a large number of trained interviewers. It's a challenge to sample citizens of a country so the resulting data end up being representative of the nation. It's difficult enough to inventory mental conditions in one country, let alone compare many.

Depression is among the most burdensome mental conditions worldwide, yet good international studies of depression have been hard to come by. Fortunately, scientists from twenty different institutions worldwide worked with the World Health Organization's World Mental Health Survey Initiative. This was a massive effort, in which data was obtained by interviewing 89,037 people in 18 different countries from 2000 to 2005. Efforts to achieve a nationally representative sample were made in all the countries. All the interviewees were interviewed face-to-face using a standardized instrument.

I want to make two short comments on the major findings reported in the journal BMC Medicine.

1. People in high income countries were more likely to have lifetime depression. Specific, people in higher-income countries (a list that included the US, Belgium, Japan and Germany) were more than 1/3 more likely to report a lifetime episode of depression than people in lower- and middle-income countries (which included countries like Ukraine and Mexico). About 15 percent of people in higher-income countries reported having a lifetime episode with depression, compared to 11 in the lower-income nations. And for the record, at 19.2 percent the U.S. had the second highest lifetime depression rate of all countries studied (France was first).

2. That said, there are basic similarities in depression across very different national contexts. Despite the many ways that countries differ from one another this study underlines important commonalities in how depression manifests. In all 18 countries studied, depression was more common in women than in men. Likewise in all countries studied, the average age of first onset was in early adulthood. Finally, while lifetime prevalences differed markedly across countries, 12 month prevalences were quite similar across nations (usually about 6 percent). This commonality, too, is important. It tells us there is something robust about depression, a common core that transcends differences in language, culture, or history.

This WHO study is a notable step forward in the international study of depression. Now with this more credible information about country-level differences, we can start to consider why depression is more common in more affluent economies. Why is it that having more money as a country does not buffer its citizenry against mood problems, and in fact, the opposite is true? Ronald Kessler, a professor at the Harvard Medical School, and one of the study authors, may be on the right track when he said,"U.S. expectations know no bounds and people in other countries are just happy to have a meal on the table."

Link to the study: