Okay, here are some supporting the OP:
Optimists have a longer life-span than pessimists, researchers have concluded.
They found that people with a positive outlook live, on average, 19% longer than those who are miserable.http://news.bbc.co.uk/2/hi/health/635292.stm
If you really want to live longer, then you can start with your attitude. Your way of thinking can not only impact the quality of your life, but also how long you actually live. In 2002, researchers at the Mayo Clinic in Rochester, Minn., found that optimistic people decreased their risk of early death by 50 percent compared with those who leaned more towards pessimism.http://www.msnbc.msn.com/id/7065794/ns/health-forbescom/
A study of 100,000 women presented at the American Psychosomatic Society's annual meeting Thursday found a strong correlation between optimism and a person's risk for cancer-related death, heart disease and early death.http://abcnews.go.com/Health/story?id=7017131&page=1
A positive outlook may help guard against heart disease and increase the chances of a long life, a new study suggests, bolstering previous findings.
Researchers from Duke University Medical Center followed 2,800 patients who'd been hospitalized with heart disease. Those with the most optimistic attitudes about making a full recovery were more likely to live longer than their pessimistic counterparts, according to lead author John Barefoot.http://www.aolhealth.com/2011/03/01/optimism-may-help-you-live-longer-study-shows/
Mayo Clinic, University of Pittsburgh, American Psychosomatic Society, Duke University Medical Center... Those are some pretty significant sources