FAAH Inhibitor Trial for Adults With Tourette Syndrome

Inclusion Criteria: * Adult between 18-60 years of age * Meet DSM IV criteria for the diagnosis of Tourette's syndrome * Significant current tic symptoms: YGTSS total tic score greater than or equal to 22 at baseline * On stable psychiatric medication regimen for a minimum of 4 weeks prior to beginning the trial. * Accepted method of birth control Exclusion Criteria: * Comorbid bipolar disorder, psychotic disorder, substance use disorder, developmental disorder or intellectual disability (IQ\<70). * Current use of medications that have significant effects on the cannabinoid or dopamine systems. Subjects will be specifically excluded for recent use (within last 8 weeks) of antipsychotic medications, dopamine agonists or psychostimulants. * Recent change (less than 4 weeks) in other medications that have potential effects on tic severity (such as alpha-2 agonists (guanfacine, clonidine or prazosin), SSRIs, clomipramine, naltrexone, lithium, anxiolytics, topiramate, baclofen etc.). Medication change is defined to include dose changes or medication discontinuation. * Recent change in behavioral treatment for Tourette syndrome or comorbid conditions (i.e. OCD) within the last 4 weeks or initiation of behavioral therapy for tics within the last 12 weeks. * Positive pregnancy test or drug screening test * History of cannabis dependence * Significant Medical Comorbidity