Most of us want, seek and wish for two things: happiness and good health (OK, OK, material wealth is up there too, but we'll get to that soon enough). For a long time, the two were viewed as being fairly independent of one another. We know that bad health makes us more likely to be unhappy, but we also know that we can be unhappy in our lives without suffering from any serious health concerns.
As far as money is concerned, studies have shown that money does increase happiness, but only up to a point. It seems that someone who is struggling below the poverty line will experience a sense of happiness as a result of joining the middle class, but someone who grows up in a middle-class household won't experience this same overall sense of contentment merely by being in the middle class. Nor, it seems, will a member of the middle class experience a similar increase in happiness by way of a bump up in lifestyle to the upper-middle class, or even into a life of luxury. It seems rappers are correct on this point: Mo' money, mo' problems. Additionally, studies of people living in Third World slums often report them being as happy as anyone else. And staking your happiness to your material status isn't such a hot long-term strategy, in case you haven't seen the faces on the trading floor after a day of heavy losses.
But there is one more relationship that needs to be examined: the effect of happiness on the human body. If we feel generally positive about life, does it actually improve our health? Does happiness affect the way we age, or does it prevent disease? And is happiness itself an indicator of longevity?