THURSDAY, June 16 (HealthDay News) -- The growing gap between the richest Americans and everyone else is making many people with middle and low incomes unhappy, researchers have found.

"Income disparity has grown a lot in the U.S., especially since the 1980s," study author Shigehiro Oishi, a psychologist at the University of Virginia, said in news release from the Association for Psychological Science. "With that, we've seen a marked drop in life satisfaction and happiness" among the 60 percent of Americans with low- and middle-class incomes, Oishi noted.

It's apparently not a shrinking bank account that makes people unhappy. Rather, the researchers explained, increasing income disparity correlates with a growing sense among many people that others are less fair and less trustworthy, resulting in a lower sense of well-being in general.

The study also found that income disparity had no effect on the happiness or feelings of trust and fairness among the richest 20 percent of people.

The research team examined data from more than 48,000 Americans who took part in the General Social Survey from 1972 to 2008. The findings are scheduled to be published in a future issue of Psychological Science.

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