Pharmacopsychiatry 2001; 34(1): 19-24
DOI: 10.1055/s-2001-15191
Original Paper
© Georg Thieme Verlag Stuttgart · New York

Influence of Treatment of Tourette Syndrome with Δ9-Tetrahydrocannabinol (Δ9-THC) on Neuropsychological Performance

K. R. Müller-Vahl1 , A. Koblenz1 , M. Jöbges2 , H. Kolbe2 , H. M. Emrich1 , U. Schneider1
  • 1Department of Clinical Psychiatry and Psychotherapy
  • 2Department of Neurology
  • Medical School Hannover, Germany
Further Information

Publication History

Publication Date:
31 December 2001 (online)

Previous studies have suggested that marijuana (cannabis sativa) and delta-9-tetrahydrocannabinol (Δ9-THC), the major psychoactive ingredient of marijuana, are effective in the therapy of tics and associated behavioral disorders in Tourette Syndrome (TS). Because there is also evidence that cannabis sativa may cause cognitive impairment in healthy users, we performed a randomized double-blind placebo-controlled crossover trial for Δ9-THC in 12 adult TS patients to investigate whether treatment of TS with a single dose of Δ9-THC at 5.0 to 10.0 mg causes significant side effects on neuropsychological performance. Using a variety of neuropsychological tests, we found no significant differences after treatment with Δ9-THC compared to placebo treatment in verbal and visual memory, reaction time, intelligence, sustained attention, divided attention, vigilance, or mood. Only when using the Symptom Checklist 90-R (SCL-90-R) did our data provide evidence for a deterioration of obsessive-compulsive behavior (OCB) and a trend towards an increase in phobic anxiety. However, these results should be interpreted with caution as SCL-90-R has known limitations on measuring OCB. We suggest that the increase in phobic anxiety is mainly due to the fact that a single-dose treatment rules out the possibility of administering the dosage slowly. In contrast to results obtained from healthy marijuana users, a single-dose treatment with Δ9-THC in patients suffering from TS does not cause cognitive impairment. We therefore suggest that further investigations should concentrate on the effects of a longer-term therapy of TS with Δ9-THC.


Dr. med. Kirsten R. Müller-Vahl

Department of Clinical Psychiatry and Psychotherapy
Medical School Hannover

Carl-Neuberg-Straße 1

30625 Hannover


Phone: +49-511-5323110

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