They discuss the possibility of abuse in brief, but the setting is physician controlled, and upping it a good deal might well result in brain damage (like early electro-convulsive therapy often did, and modern ECT still does to some extent).
http://www.popsci.com/popsci/science/7f ... drcrd.html

This woman, one of a handful with the brain electrode implants, seems to be responding quite well. Still too early to tell how others will fare in larger controlled studies.