Economists, politicians and business executives typically spend their lives striving for the same goal – bringing prosperity to their communities. Why? The answer appears simple. More money buys more options and security, which, ultimately, leads to greater happiness.

But a new study challenges the wisdom of this thinking.

The research team, led by Dr. Evelyn Bromet, a professor of psychiatry at State University of New York at Stony Brook, interviewed 89,000 people in a 18 countries, from very poor places to the world's most developed economies. Using a standard set of questions known as the WHO Composite International Diagnostic Interview, they attempted  to gauge the prevalence of depression. Their findings: Citizens of wealthier countries are more likely to be depressed. Overall, 15 percent of people in the wealthy countries surveyed experience depression, compared to 11 percent in the low and middle-income countries.

The researchers aren't sure why but offer several possible explanations, including less family and community support and higher expectations in wealthy countries and a reluctance of people in lower-income countries to admit to depression.

India named world's most depressed nation

Overall, one in seven people (15 per cent) in high-income countries is likely to get depression over their lifetime, compared with one in nine (11 per cent) in middle- and low-income countries.

But there are exceptions to the rule. India recorded the highest rate of major depression in the world, at 36 per cent. It is going through unprecedented social and economic change, which often brings depression in its wake. The global study, based on interviews with 89,000 people, shows that women are twice as likely to suffer depression as men.