Negative, stress-related emotions cause disease, whereas positive emotions suppress the release of stress hormones and help us fight disease. Love and Trust Romantic love increases our immunity to colds. A Harvard psychologist found that when people love and care significantly about others, their antibody production increases, making it easier for them to fight off upper respiratory viruses. And in a study of people who had eye surgery, patients who trusted their eye surgeons had a smoother recovery than patients who didn't. When a patient experiences an emotion, or a series of thoughts, the PET scan takes images of those mental changes.
PET measures the patient's cerebral blood flow, and documents the brain's changing hormonal balance.
During chronic stress and pessimism, the brain appears abnormally different than it does in a cheerful person. PET scans are proving what psychologists have been saying for years. If you don't like yourself very much, if you spend a lot of time trying to change yourself from a sow's ear to a silk purse, you will probably suffer with chronic stress. Berating yourself and the decisions you make, always thinking you'd be happier if you had more money, a bigger house, or a better car, emotions like these wear down your mind and body, triggering stress-response chemicals. You're less likely to suffer from chronic stress if you have moderate to high self-esteem.