A study in the journal, Perspectives on Psychological Science, conducted by
Dr. Ed Diener of the University of Illinois at Urbana-Champaign appears to indicate that moderately happy people are wealthier and healthier than most.
The study also found that the happiest students had lower grade point averages than less happy peers. Other studies have shown that the happiest people may not live as long as moderately happy people. 120,000 people from 96 countries were surveyed.
Diener believes that extremely happy people are not as driven as less happy people. They are "happy" with their lives and less likely to want to change it. Being extremely happy can also have an adverse effect on the cardiovascular system.