Treatment of Tourette’s Syndrome With Delta-9-Tetrahydrocannabinol

Mr. A, a 25-year-old man, was diagnosed with attention deficit hyperactivity disorder at age 6. Motor and vocal tics started at age 10. During adolescence, he developed obsessive-compulsive behavior, anxiety, lack of impulse control, and self-injurious behavior. The diagnosis of Tourette’s syndrome according to DSM-IV criteria was made at age 22. At age 19, he started smoking marijuana. When using 2–3 g/day, he noted a marked improvement of both vocal and motor tics and associated behavioral disorders. Therefore, he stopped less effective medical treatment with pimozide.

In an uncontrolled open clinical trial, we investigated whether Δ⁹-THC is effective in the therapy of Tourette’s syndrome. Written informed consent was obtained from the patient after complete description of the study. The local ethics committee approved the study.

Mr. A was treated once with 10 mg of Δ⁹-THC. (He was unmedicated and had stopped smoking marijuana 3 days before.) Using the section on tic symptoms of the Tour­ette’s Syndrome Global Scale, we found that Mr. A’s total tic severity score was 41 before treatment and was reduced to 7 just 2 hours after treatment. Both motor and vocal tics improved and coprolalia disappeared. The improvement began 30 minutes after treatment and lasted for about 7 hours; no adverse effects occurred. To measure cognitive functions, we performed neuropsychological tests, which showed improved signal detection and sustained attention and reaction time after treatment. Mr. A himself noted an improvement of motor and vocal tics of about 70%. Furthermore, he felt an amelioration in attention, impulse control, obsessive-compulsive behavior, and premonitory feeling.