Perhaps the adage "money can't buy happiness" has more truth than we think.
That's because there are many studies that point to the conclusion that wealth and happiness are not positively correlated, according to the Harvard Business Review. One reason, for instance, is that wealth appears to make people less generous. In a study by researchers at the University of California, Berkeley, participants playing a game of Monopoly grew progressively meaner as their wealth grew, by talking down to their poorer competitors and assuming more dominant positions. Most egregiously, they also consumed a larger portion of a bowl of pretzels meant to be shared equally.
Similarly, another study found that when participants were given $10 and told they could contribute some or all of it to another person, the wealthier subjects contributed about 44% less. In the real world, researchers have discovered that rich people give proportionally less of their income to philanthropic causes.
Wealthier people are more isolated, too--which has a negative effect on happiness. Wealth engenders isolation because acquiring more money predisposes people toward keeping their distance—or more simply, they might not need their peers in the same way. Additionally, as people climb into higher tax brackets, they value independence more and social connections less.
Still, that has key implications for personal happiness. Results from a Notre Dame study found that generosity indicators—such as giving money, volunteering and being available to friends—were highly correlated with happiness. Similarly, generosity had a positive effect on happiness in 93% of 136 countries studied.
That's also because we tend to be happy when we're more social. Studies show we can't be happy without at least one meaningful, close relationship. The more vigorous social life we enjoy, the more likely we are to experience positive emotions.
If you are lucky enough to be rich, be mindful of your scientifically-proven tendency to isolate yourself. And if you're still feeling down, try giving some of your wealth away to charity.