Is there a link between personality and health? It stands to reason that optimism and a sunny disposition could contribute to long life......

It used to be said that good people were short-lived - a belief honed in earlier times when infants and children frequently did not grow up, and anybody (good-natured or not) could suddenly be felled by infectious diseases. In scientific studies, it's not easy to prove that positive or negative attitudes affect health.

There is a body of evidence that well-adjusted, socially stable, well-integrated people have a lower risk of disease and premature death than loners and the chronically discontented and pessimistic. Most research finds that optimism is associated with longer life, though it certainly does not guarantee it.

In a 23-year study done in a small town in Ohio by researchers from Yale and Miami Universities, people over 50 who viewed aging as a positive experience lived an average of 7.5 years longer than those who did not - a big gap. People got more mileage out of optimism than from lowering blood cholesterol levels. And other things being equal, they got more mileage out of their will to live than other psychological factors.

Other research has also linked optimism with longevity. Mayo Clinic researchers followed 227 people whose personal traits had been evaluated 30 years earlier. Those classified as optimists had half the risk of early death compared to those classified as pessimistic or 'mixed'. The optimists had fewer problems as they aged - fewer limitations, less pain, and more energy.

In a study called 'Is the glass half empty or half full?' Harvard researcher Dr Laura Kubzansky found that optimism as evaluated in the way people explain events in their lives to themselves and others, was protective against heart disease. Other studies have found that optimists tend to recover faster after coronary bypass surgery than pessimists. Dr Kubzansky and other researchers believe that negative emotions and chronic pessimism should be regarded as risk factors for heart disease.
 

Here are a few ways that personality might alter health and life expectancy:

- Chronic frustration and anger could lead to smoking, excessive drinking, or poor eating habits. An optimistic person might be more strongly motivated to change bad habits - or not have them in the first place.

- Optimism might lead a person to seek and follow medical advice, and to live in ways that work to prevent illness.

- It's possible that optimism has a positive impact on the immune system. Studies so far, though, have been inconclusive.