It's possible to "think" yourself to death

Back in the 1940s, Harvard physiologist Walter Bradford Cannon—best known for coining "fight or flight response"—explored stories of "voodoo death" in which people apparently died from curses. According to Canon, these cases couldn't all be relegated to legend or superstition but that it might be possible that fear and belief led these people to "think" themselves to death. Now, medical research suggests there may be something to "dysexistential syndrome," described by University of Portsmouth survival psychology researcher John Leach as the pathology of "psychogenic death" or willing yourself to die. From Salon:

Since Cannon first described the "fight or flight," response, a third option has been added to the list: freeze. This is known as "passive coping," and it happens when a threat is perceived as inescapable. It's a way for the organism to conserve energy until the threat passes.

But sometimes the threat — or the perception of it — doesn't pass. In that case, a person can lose hope of escape and, "the prefrontal cortex deliberately inhibits the production of dopamine in the basal ganglia to well below its functional level," says Leach. "That's associated with the feeling of hopelessness." If this continues for too long, it can become impossible to restart dopamine production.  The person in this situation begins a "spiral of disengagement," which consists of five stages: 

      1) Withdrawal

      2) Apathy

      3) Aboulia (loss of emotional response, initiative and willpower)

      4) Akinesia (lack of response to external stimuli, even to pain).

Most people who enter this neurological tailspin will emerge from it before they hit bottom. They take in new information. They adapt to the new situation. But the few who don't may find themselves at stage five: Psychogenic death. The light goes out of their eyes. They say their goodbyes. They may perk up briefly as if they finally have a goal they can imagine, a solution to their problem: That new goal is death. And within a day or so, they're gone.

"Inside psychogenic death, the phenomenon of 'thinking' yourself to death" by Frank Bures (Salon)