[metrocartockasur]

There is evidence to suggest that people who are chronically dissatisfied with their lives/unhappy have an increased risk of developing cancers and heart disease ( and other ailments that involve immune system dysfunction). It is thought that, because of the alteration from the normal of various hormones(adrenalins and cortisol, in particular) in (physiological) stress states alter the immune response negatively, thereby increasing the likelihood of certain diseases. In survivors of heart attacks, persistent depression (nearly all of such folks go through a period of depression, as is true for most close brushes with death) significantly increases the risk of further heart attacks and death.

I believe, from my own experiences as a physician, that people who no longer want to be alive die much sooner than otherwise. As a personal example, my wife's mother, a very strong personality, was ill and in the hospital with an infection(diverticulitis). She was improving and doing quite well when, one evening, she told my wife "I don't want to be here any more ... tell everyone I love them". She was found dead in bed (in the hospital) at 3 AM - there had been no particular change in her condition that evening and there was no reason to expect any problems.