Brief ReportsOral Δ9-Tetrahydrocannabinol Improved Refractory Gilles de la Tourette Syndrome in an Adolescent by Increasing Intracortical Inhibition A Case ReportHasan, Alkomiet MD*; Rothenberger, Aribert MD†; Münchau, Alexander MD‡; Wobrock, Thomas MD*; Falkai, Peter MD*; Roessner, Veit MD§ Author Information From the Departments of *Psychiatry and Psychotherapy, and †Child and Adolescent Psychiatry, Georg-August-University Göttingen, Göttingen; ‡Department of Neurology, University of Hamburg, Hamburg; and §Department of Child and Adolescent Psychiatry, University of Dresden, Dresden, Germany. Received July 30, 2009; accepted after revision December 31, 2009. Reprints: Veit Roessner, MD, Department of Child and Adolescent Psychiatry, University of Dresden, Goetheallee 12, 01309 Dresden, Germany (e-mail: [email protected]). Journal of Clinical Psychopharmacology: April 2010 - Volume 30 - Issue 2 - p 190-192 doi: 10.1097/JCP.0b013e3181d236ec Buy Metrics Abstract Objective: To describe the clinical course of the Δ9-tetrahydrocannabinol (Δ9-THC) treatment of a boy with Gilles de la Tourette Syndrome (TS) and comorbid attention-deficit/hyperactivity disorder (ADHD) in relation to Δ9-THC plasma levels and intracortical inhibition measured by transcranial magnetic stimulation. Methods: The clinical course and pharmacological and neurophysiological measures are reported in a 15-year-old boy with treatment refractory TS plus ADHD leading to severe physical and psychosocial impairment. Results: Administration of Δ9-THC improved tics considerably without adverse effects, allowing parallel stimulant treatment of comorbid ADHD. Along with the Δ9-THC treatment, intracortical inhibition was increased, reflected in the enhanced short-interval intracortical inhibition and the prolongation of the cortical silent period. Conclusions: Our observation suggests that Δ9-THC might be a successful alternative in patients with severe TS refractory to classic treatment. Particularly in the case of stimulant-induced exacerbation of tics, Δ9-THC might enable successful treatment of comorbid ADHD. The enhancement of intracortical inhibition might be mediated by modulating release of several neurotransmitters including dopamine and γ-aminobutyric acid. Further studies are needed to substantiate our findings. © 2010 Lippincott Williams & Wilkins, Inc.