Tо see if hypnоsis cоuld reduce chronic pаin, investigаtors rаndomly assigned 120 volunteers with osteoarthritis to either hypnosis therapy or standard treatment. Pain levels were checked among the subjects every three months during the 12-month study using validated pain measures. Those assigned to the hypnosis group reported reduced pain compared to those in the standard treatment group after three and six months, but not after nine and 12 months, of follow up.