Hans Selye, an endocrinologist, developed the <em>"Stress Theory."</em> He showed the relationship of <em>"stress"</em> to the person's development of disease.
Under stress, <em>a person's body experiences changes</em>. The person tries to cope with these through three stages: <em>Alarm Reaction Stage, Resistance Stage and Exhaustion Stage. </em>It is at the<em> last stage</em> that a person's immune system is placed at a huge risk. Once the person is exposed to a stressor for a period of time, he becomes hopeless and his body tends to give up coping. He then succumbs to <em>stress-related illness.</em>