Not only does your personality affect the medical conditions you are likely to experience, but it also determines how you respond to treatments. An optimist will respond to the same treatment in a different way than a pessimist.
Individuals with such a personality are not at all adventurous and let incidences control their lives. A submissive person is thus more likely to come down with a chronic illness, such as arthritis. Anyone with this kind of personality needs to make an effort to be more bold and sociable for their health.
List down the pros and cons of your personality, and how each benefits and/or affects your health. It is extremely difficult to change your personality, but try to find alternatives that suit you, and will help your health in the long run. Try to maintain an outlook that will boost your health and also prolong your life.