You can learn more about some of the early results of DBS in patients with these mental illnesses here:
http://www.ctvnews.ca/health/health-headlines/canadian-researchers-use-electricity-to-stimulate-brains-of-alzheimer-s-patients-1.2221623
http://www.ctvnews.ca/w5/deep-brain-stimulation-offers-treatment-hope-for-severe-anorexia-patients-1.2266141