VS Ramachandran's Phantoms in Brain (p.224): "A second example of a genuine anomaly is multiple personality dis­ order or MPD, which in my view may turn out to

VS Ramachandran's Phantoms in Brain (p.224): "A second example of a genuine anomaly is multiple personality dis­ order or MPD, which in my view may turn out to be just as important for medicine as continental drift was for geology. To this day MPD con­tinues to be ignored by the medical community even though it provides a valuable testing ground for the claims of mind-body medicine. In this syndrome-immortalized by Robert Louis Stevenson in Dr. Jekyll and Mr. Hyde-a person can assume two or more distinct personalities, each of which is completely unaware, or only dimly aware, of the others. Again, there have been occasional reports in the clinical literature that one personality can be diabetic while the other is not, or that various vital signs and hormone profiles can be different in the two personalities. There is even a claim that one personality can be allergic to a substance while the other is not and that one might be myopic-or nearsighted­ whereas the other has 20/20 vision."