Our bodies were created to take care of themselves for the most part, and we sometimes botch things up when we try to alter our system with drugs. For many years scientists and lay persons have done studies, research, and performed experiments concerning the effects of laughter on one's physical and mental health. These studies have proven that when we laugh, there is an actual chemical change in our bodies that helps to ease pain and release stress.
Laughter is a coping mechanisim for the normal stress of life.
Distressful events and major life changes can obviously impact our bodies negatively. It has been proven that stress depletes the immune system's ability to fight against disease. Indirectly, stress is probably our number one killer. It effects us physically and mentally, wearing our immune systems down, and causing us to be more susceptible to sickness and disease. We try to treat the disease, when we really need to treat the cause.