Another interesting study that I have come across on my Open University course; the benefits of positive thinking!
A study by Maruta et al. (2002) reports that pessimists have a lower quality of life and below average physical and mental health. Your 'explanatory style' has a significant effect on your health.
"Wellness of being is not just physical but attitudinal. How you perceive what goes on around you and how you interpret it may have an impact on your longevity, and it could affect the quality of your later years."