Globally, depression is the second-leading cause of disability, and the Middle East and North Africa have the highest concentration of people with the disorder, according to a new study published in the journal PLOS Medicine.
Researchers at Australia’s University of Queensland used pre-existing data on the prevalence, incidence and duration of depression to figure out the social and public health burden of the condition throughout the world. They found that slightly more than 4 percent of the world’s population are diagnosed with the disorder.
The study found that more than 5 percent of the population suffers from depression in the Middle East, North Africa, Sub-Saharan Africa, Eastern Europe and the Caribbean.
The most depressed country is Afghanistan, where more than 20 percent suffer from the disorder, while the least depressed is Japan, with less than 2.5 percent.
Depression often shows up in regions with conflict and in the presence of other serious epidemics. Not surprisingly, Afghanistan, Honduras and the Palestinian territories are the three most depressed regions.
“In the case of North Africa/Middle East, conflict in the region increased the prevalence of [depression], leading to a higher burden ranking,” wrote the researchers. In sub-Saharan Africa, however, diseases such as malaria and AIDS have crowded out depression as the top public health problem.
Social scientists have found that people between the ages of 16 and 65 tend to suffer depression at much higher rates. That age factor, along with explosive population growth, explains why the burden of depression has increased by nearly a third since 1990, researchers say.
The investigators caution that reliable depression surveys don’t even exist for some low-income countries, driving the researchers to create their own estimates based on statistical regression models.
For example, people who live in countries with greater awareness of and easier access to mental health services are naturally going to have a higher rate of diagnosis. This may help explain the unusually low rate of depression in Iraq, for example, where public health services are poor.
Also, populations that often hold taboos against mental health problems—for example in East Asia— also drive down diagnosis rates, giving a false lower measure of clinical depression in that area.
Source: PLOS Medicine