Pharmacopsychiatry 2002; 35(2): 57-61
DOI: 10.1055/s-2002-25028
Original Paper
© Georg Thieme Verlag Stuttgart · New York

Treatment of Tourette's Syndrome with Δ9-Tetrahydrocannabinol (THC): A Randomized Crossover Trial

K.  R.  Müller-Vahl1 , U.  Schneider1 , A.  Koblenz1 , M.  Jöbges2 , H.  Kolbe2 , T.  Daldrup3 , H.  M.  Emrich1
  • 1Department of Clinical Psychiatry and Psychotherapy, Hanover Medical School
  • 2Department of Neurology, Hanover Medical School
  • 3Institute of Legal Medicine, Heinrich Heine University, Düsseldorf, Germany
Further Information

Publication History

15. 12. 2000

3. 9. 2001

Publication Date:
12 April 2002 (online)

Anecdotal reports in Tourette's syndrome (TS) have suggested that marijuana (cannabis sativa) and delta-9-tetrahydrocannabinol (Δ9-THC), the major psychoactive ingredient of marijuana, reduce tics and associated behavioral disorders. We performed a randomized double-blind placebo-controlled crossover single-dose trial of Δ9-THC (5.0, 7.5 or 10.0 mg) in 12 adult TS patients. Tic severity was assessed using a self-rating scale (Tourette's syndrome Symptom List, TSSL) and examiner ratings (Shapiro Tourette's syndrome Severity Scale, Yale Global Tic Severity Scale, Tourette's syndrome Global Scale). Using the TSSL, patients also rated the severity of associated behavioral disorders. Clinical changes were correlated to maximum plasma levels of THC and its metabolites 11-hydroxy-Δ9-tetrahydrocannabinol (11-OH-THC) and 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH). Using the TSSL, there was a significant improvement of tics (p=0.015) and obsessive-compulsive behavior (OCB) (p = 0.041) after treatment with Δ9-THC compared to placebo. Examiner ratings demonstrated a significant difference for the subscore “complex motor tics” (p = 0.015) and a trend towards a significant improvement for the subscores "motor tics" (p = 0.065), “simple motor tics” (p = 0.093), and “vocal tics” (p = 0.093). No serious adverse reactions occurred. Five patients experienced mild, transient side effects. There was a significant correlation between tic improvement and maximum 11-OH-THC plasma concentration. Results obtained from this pilot study suggest that a single-dose treatment with Δ9-THC is effective and safe in treating tics and OCB in TS. It can be speculated that clinical effects may be caused by 11-OH-THC. A more long-term study is required to confirm these results.


Dr. Kirsten R. Müller-Vahl

Department of Clinical Psychiatry and Psychotherapy
Medical School Hannover

Carl-Neuberg-Str. 1

30625 Hannover