Pardon me if I say “well, duh.” The Times says:
Happiness is clearly real, related to objective measures of well-being. Happier people have lower blood pressure and get fewer colds. But using it to guide policy could be tricky. Not least because we donâ€™t quite understand why it behaves the way it does. Men are unhappiest at almost 50, and women at just after 45. Paraplegics are not unhappier than healthy people. People who live with teenagers are the unhappiest of all.