Depression rates are higher in richer countries than in low- or middle-income nations, according to researchers who compared socioeconomic conditions with depression.
About 121 million people worldwide have depression, which can harm people's quality of life by affecting their ability to work and form relationships. Severe depression can lead to suicide and causes 850,000 deaths every year.
Detailed interviews with more than 89,000 people in 18 nations revealed that 15% of people in high-income countries were likely to get depression during their lifetime, compared with 11% of those in low- or middle-income countries. About 5.5% of people in high-income countries had depression within the previous year.
High-income countries had higher rates of major depression (28% vs. 20%), and especially high rates (more than 30%) were found in the United States, France, the Netherlands and India. China had the lowest rate of major depression (12%).
The average age at onset of depression was nearly two years younger in low-income countries, the investigators found.
More women suffer depression
Women were twice as likely as men to suffer depression, and the major contributing factor was loss of a partner because of death, divorce or separation.
The study, published in the journal BMC Medicine, was conducted by researchers at 20 centres in conjunction with the World Health Organization World Mental Health Survey Initiative.
"We have shown that depression is a significant public-health concern across all regions of the world and is strongly linked to social conditions. Understanding the patterns and causes of depression can help global initiatives in reducing the impact of depression on individual lives and in reducing the burden to society," Evelyn Bromet, of the State University of New York at Stony Brook, said.
The U.S. National Institute of Mental Health has more about depression.
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