The BBC recently ran an interesting series of documentaries entitled 'The Story of Science: Power, Proof, and Passion' presented by Michael Mosley. Episode 6 looked at the science of the mind, and there is a fascinating section on Jean-Martin Charcot. Charcot was interested in hysteria, a condition whose symptoms could include blindness, tremors, paralysis, loss of speech, and fits. The conventional thinking at the time was that hysteria was a neurological condition with an organic cause. Charcot used hypnosis though, and found that he could induce and relieve symptoms of hysteria by using appropriate hypnotic suggestion. Nowadays we've stopped using the term hysteria, but medically unexplained symptoms are often termed a 'conversion disorder', and hypnosis is still a useful treatment. 

There is an interesting section in the documentary where David Oakley, the director of the UCL Hypnosis Unit uses hypnosis to induce the symptoms of dystonia (tremor) and hemianopia (loss of part of the visual field). Some researchers use this approach to model certain neurological conditions, and it's well worth watching.

I have embedded the video below. You have to skip to about 7 minutes in to get to the section on Charcot and hypnosis.

Link to the video at YouTube