Antonio Melechi explores one of the bizarre corners of the medical literature in his book Fugitive Minds (p211, ISBN 0099436272):
In 1979, the Journal of the Tennessee Medical Association announced that the ‘Walking zombie syndrome’ – a condition in which depression and withdrawal led individuals to unconsciously believe that they were dead – was on the increase. Illness, coma, high fever, operations performed under partial anaesthesia, and bereavement were, it claimed, just some of the situations through which a ‘death suggestion’ could be unwittingly assimilated.
Fortunately, there was, according to the hypnotherapists who ‘discovered’ the condition, one simple and effective cure: age regression. By returning patients to the event which triggered the ‘death suggestion’, the ‘symptoms of death’ could, it was claimed, be at once relived and remedied.
Although most physicians remained unaware of the diagnosis or treatment, the pseudo-illness continued to claim factitious casualties. By the late 1980s, the United States had apparently overtaken Haiti as the zombie capital of the world. According to one estimate, there were ‘thousands of walking zombies on the streets of every city’.