Habit Reversal (HRT) is a behavioral treatment for Tourette Syndrome. Individuals learn to identify early sensations preceding tics, learn to apply relaxation techniques, and to apply antagonistic, competing movements to inhibit the occurrence of tics. Consistent with earlier findings, preliminary results from a TSA-sponsored controlled treatment trial conducted at the Massachusetts General Hospital indicate that habit reversal can reduce (inhibit) tics. However, current investigations of the efficacy of habit reversal leave some important questions unanswered. First, HRT may only affect tics addressed in a treatment that provides patients with a “circumscribed” skill to inhibit specific tic responses. On the other hand, inhibitory skills may generalize to tics not addressed in treatment, and may even influence the pathophysiological mechanisms underlying impairments in response inhibition in TS. In addition, current investigations may have underestimated beneficial effects of supportive psychotherapy by including only relatively global measures of psychosocial functioning. Thus, in this second year project we will conduct a multimodal assessment of the efficacy of habit reversal compared to supportive psychotherapy. This includes (1) a comprehensive assessment of generalization effects of habit reversal over the course of treatment and, follow-up, (2) a comprehensive cognitive neuroscience investigation to determine whether response inhibition abilities in patients with TS change differently with habit reversal in comparison to supportive psychotherapy and (3) a comprehensive assessment of psychosocial functioning on multiple dimensions of patients undergoing both treatment conditions. Forty adult subjects meeting DSM-IV criteria for TS will be recruited from the Obsessive-Compulsive Disorder/Tourette’s Disorder Clinic at the Massachusetts General Hospital, and also via advertisement in local newspapers. After a one month baseline evaluation period, research participants will be randomly assigned to one of two groups: individual habit reversal or individual supportive psychotherapy. Subjects in both groups will be treated for 14 sessions (over a period of 20 weeks). Assessments of tic severity (e.g. Yale-Global Tic Severity Scale; Leckman et al.;1989), associated psychopathology (e.g. OCD, major depression) and psychosocial functioning will be conducted twice at baseline (every other week), and every four weeks during the 20-week treatment as well as at 6 month-follow-up. Response inhibition pre and post treatment will be assessed using computerized tasks. In addition 20 healthy volunteers will complete the response inhibition assessment to serve as a comparison group to the subjects. Preliminary results from the first year indicate that habit reversal is more effective than supportive psychotherapy in reducing tics. While small habit reversal treatment effects do appear to generalize to tics not yet addressed in treatment. Before the beginning of treatment, patients with TS are impaired in measures of response inhibition compared to healthy controls. Thilo Deckersbach, Ph.D. Massachusetts General Hospital, Charlestown, MA Award: $37,500 (Year 2) Tourette Association of America Inc. – Research Grant Award 2001-2002