WEDNESDAY, Dec. 15 (HealthDay News) -- People's happiness doesn't necessarily increase as their income rises, a new study suggests.

Researchers examined the link between economic growth and happiness in 37 countries over a minimum of 10 years and an average of 22 years. The countries included in the study were rich and poor, ex-Communist and capitalist.

The findings challenge "recent claims that there is a positive long-term relationship between happiness and income, when in fact, the relationship is nil," study author Richard Easterlin, a professor of economics at the University of Southern California, said in a USC news release.

"With incomes rising so rapidly in [certain] countries, it seems extraordinary that no surveys register the marked improvement in subjective well-being that mainstream economists and policy makers worldwide expect to find," he noted.

As examples, Easterlin cited Chile, China and South Korea. Per capita income in those countries has doubled in less than 20 years, but surveys had shown mild declines in life satisfaction in those nations.

"Where does this leave us? If economic growth is not the main route to greater happiness, what is? We may need to focus policy more directly on urgent personal concerns relating to things such as health and family life, rather than on the mere escalation of material goods," Easterlin said.

The study was published in the Dec. 13 online edition of the journal Proceedings of the National Academy of Sciences.

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