A new study by researchers at the University of Queensland in Australia shows that rates of depression vary significantly from country to country—and patterns of depression worldwide can be quite surprising. The highest rates were reported in the Middle East, North Africa, and Eastern Europe, where more than 5 percent of the population suffers from depression. The lowest rates were in East Asia, Southeast Asia, and Australia/New Zealand. The least depressed country is Japan, with a rate of less than 2.5 percent. On average, approximately 4 percent of the world’s population has been diagnosed with depression. The study also calculated the “burden of depression” for each country, that is, the number of healthy years lost to depression or depression-related premature death. Using this metric, depression becomes the second-leading cause of disability worldwide.

The authors of the study caution that their findings were based on preexisting data on the prevalence, incidence, and duration of depression; therefore, factors such as access to diagnosis and cultural attitudes about mental illness may have skewed results. The authors of the study also said that reliable surveys from some poorer countries were not available.

The Washington Post created a map of clinical depression rates based on the Queensland study; click on the link to learn more about these findings.