Significant eyesight changes have been found in people with multiple personality disorder (MPD)*. In some cases, one personality** has good vision while another is nearsighted. (Goleman, D., 'Probing the enigma of multiple personality', The New York Times, 28 June 1988.) This means that eyesight is not constant or all the personalities, sharing the same eyes, would all have the same vision.

Other physiological changes have been documented in people with MPD, including:

Eye color changes between personalities Severe allergies in one personality but not in another Asthma in one personality but not in another Diabetes in one personality but not in another Even x-rays can differ between different personalities

NLP Practitioners who work with people who have physical ailments know that people can, in a sense, "re-program" themselves to deal with and sometimes cure their own ailments. I know of several people who have recovered from diabetes, asthma, allergies, and who have changed their vision back to 20/20 when medical doctors and optometrists told them they were stuck with their ailments for life.

While conventional wisdom would say that's not possible because these are physical ailments, my ears perked up when I heard that people with MPD sometimes have physiological changes when they change personality. If multiples can do it by accident, it seems plausible that we who are lucky enough to have some control over our moods and minds can do it on purpose. Again, NLP Practitioners know from both training and experience that the mind has tremendous influence over the body (some would say they are same). What excites me about the physiological changes that people with MPD experience is the scientific evidence it provides that, in a sense, explains how it is possible for something like NLP to affect people's physical ailments.

In my own experience as a Practitioner, I recently helped a young woman with exercise-induced asthma recover from her ailment and be able do vigorous exercise without the need to rely on her inhaler. She gained fifteen pounds of muscle in her first two months at college on a full basketball scholarship how's that for vigorous exercise and only needed to use her inhaler once.

*Note: MPD has been renamed by the American Psychological Association as Dissociative Identity Disorder (DID).