title: Delta 9-tetrahydrocannabinol (THC) is effective in the treatment of tics in Tourette syndrome: a 6-week randomized trial.
abstract: BACKGROUND
  Preliminary studies suggested that delta-9-tetrahydrocannabinol (THC), the major psychoactive ingredient of Cannabis sativa L., might be effective in the treatment of Tourette syndrome (TS). This study was performed to investigate for the first time under controlled conditions, over a longer-term treatment period, whether THC is effective and safe in reducing tics in TS.
  
  
  METHODS
  In this randomized, double-blind, placebo-controlled study, 24 patients with TS, according to DSM-III-R criteria, were treated over a 6-week period with up to 10 mg/day of THC. Tics were rated at 6 visits (visit 1, baseline; visits 2-4, during treatment period; visits 5-6, after withdrawal of medication) using the Tourette Syndrome Clinical Global Impressions scale (TS-CGI), the Shapiro Tourette-Syndrome Severity Scale (STSSS), the Yale Global Tic Severity Scale (YGTSS), the self-rated Tourette Syndrome Symptom List (TSSL), and a videotape-based rating scale.
  
  
  RESULTS
  Seven patients dropped out of the study or had to be excluded, but only 1 due to side effects. Using the TS-CGI, STSSS, YGTSS, and video rating scale, we found a significant difference (p <.05) or a trend toward a significant difference (p <.10) between THC and placebo groups at visits 2, 3, and/or 4. Using the TSSL at 10 treatment days (between days 16 and 41) there was a significant difference (p <.05) between both groups. ANOVA as well demonstrated a significant difference (p =.037). No serious adverse effects occurred.
  
  
  CONCLUSIONS
  Our results provide more evidence that THC is effective and safe in the treatment of tics. It, therefore, can be hypothesized that the central cannabinoid receptor system might play a role in TS pathology.
authors.affiliation: Department of Clinical Psychiatry and Psychotherapy, Medical School of Hannover, Hannover, Germany. mueller-vahl.kirsten@mh-hannover.de
authors.forename: Kirsten R
authors.initials: KR
authors.lastname: Müller-Vahl
authors.forename: Udo
authors.initials: U
authors.lastname: Schneider
authors.forename: Heidrun
authors.initials: H
authors.lastname: Prevedel
authors.forename: Karen
authors.initials: K
authors.lastname: Theloe
authors.forename: Hans
authors.initials: H
authors.lastname: Kolbe
authors.forename: Thomas
authors.initials: T
authors.lastname: Daldrup
authors.forename: Hinderk M
authors.initials: HM
authors.lastname: Emrich
mesh_terms: D000293:Adolescent; D000328:Adult; D004311:Double-Blind Method; D013759:Dronabinol / Q000627:therapeutic use*; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010555:Personality Inventory; D010919:Placebos; D011569:Psychiatric Status Rating Scales; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug / Q000187:drug effects / Q000502:physiology; D012720:Severity of Illness Index; D020323:Tics / Q000188:drug therapy* / Q000503:physiopathology; D005879:Tourette Syndrome / Q000188:drug therapy* / Q000503:physiopathology; D016896:Treatment Outcome
chemical_list: D010919:Placebos; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug; D013759:Dronabinol