Objective: To investigate the effects of topiramate on Tourette syndrome (TS).
Background: Dopamine-receptor-blocking drugs have been traditionally used to control tics in patients with TS, but these neuroleptics are associated with potentially limiting side effects.
Methods: This is a randomised, double-blind, placebo-controlled, parallel group study. To be included in the study, subjects required a DSM-IV diagnosis of TS, were 7-65 years of age, had moderate to severe symptoms (Yale Global Tic Severity Scale (YGTSS) > or =19), were markedly impaired as determined by the Clinical Global Impression (CGI) scale severity score of > or =4 and were taking no more than one drug each for tics or TS comorbidities.
Results: There were 29 patients (26 males), mean age 16.5 (SD 9.89) years, randomised, and 20 (69%) completed the double-blind phase of the study. The primary endpoint was Total Tic Score, which improved by 14.29 (10.47) points from baseline to visit 5 (day 70) with topiramate (mean dose 118 mg) compared with a 5.00 (9.88) point change in the placebo group (p = 0.0259). There were statistically significant improvements also in the other components of the YGTSS as well as improvements in various secondary measures, including the CGI and premonitory urge CGI. No differences were observed in the frequency of adverse events between the two treatment groups.
Conclusion: This double-blind, placebo-controlled trial provides evidence that topiramate may have utility in the treatment of moderately severe TS.
Trial registration: ClinicalTrials.gov NCT00206323.