Depression is the most strongly implicated trait. However, it is important to keep in mind that the links between psychological states and disease are relatively weak. Stress and Resistance to Disease Physical and psychological factors interact to determine health. Psychosomatic disorders involve the interaction of psychological and physical determinants. Psychoneuroimmunology studies the relationships among psychological processes, the nervous system, and the immune system.
People vary in their ability to cope with stress.
The connection between emotion and health is complex. Unhealthy habits may cause the disease. Something else entirely may affect both emotion and disease.