For many patients diagnosed with a neuropsychiatric disorder, the ability to drive a car plays a crucial part in their functional autonomy. Surprisingly, there were no data available in a PubMed search performed in March 2011 concerning Tourette's Syndrome and driving ability. According to our knowledge , this is the first report on driving ability in a drug-free Tourette' s patient as well as after cannabinoid therapy. “ Mr. H. was a 42-year-old truck-driver, with Tourette's Syndrome since the age of six. On the day of admittance to our hospital, he exhibited coprolalia, multiple motor tics such as head, arm and leg jerking, and repeatedly standing up and down. Mostly, he was suffering from ruminating obsessive thoughts. Diagnostic tests including lumbar puncture, magnetic resonance imaging, and electroencephalography, did not produce any pathological findings. Neuropsychological testing was unremarkable with regard to attention, memory and executive functions. IQ testing revealed an average level of intelligence. A review of the patient's medical history showed that all standard treatments for tic disorders (dopamine-blocking agents, alpha-2- agonists, clonazepam, and tetrabenazine) had proved ineffective. Although there is still a lack of good controlled evidence to support the use of cannabinoids in treating tics in people with Tourette's syndrome, experimental therapy with ? 9-tetrahydrocannabinol (THC) was started. Within 2 weeks, the daily dose was raised to 15 mg. Tics decreased significantly with scores on the Yale Global Tic Severity Scale being reduced by 75% (Global Severity Score dropping from 89 to 22). Since Mr. H.'s job required daily driving, he asked for a treatment that would not affect his driving skills. Therefore, his driving ability was assessed with computerized tests, according to the German guidelines for road and traffic-safety, in an off/on-design. Both, in the drug-free phase and during THC therapy, the criteria according to German regulations were met in all functional domains investigated (i.e. visual perception, capacity of reaction, concentration and stress tolerance). According to these criteria, a test has to be considered a failure if a patient falls below the threshold of 1 standard deviation below the mean in test parameters (percentage b16). In comparison with the drug-free phase, there was a clear improvement in concentration (from percentage 39 to 58) and visual perception (from percentage 44 to 72) during THC therapy.” Tourette's syndrome is associated with motor and vocal tics and a range of cognitive and behavioural features. To date, there is a controversial debate whether the use of cannabinoids causes cognitive impairment in healthy subjects. In Tourette's patients, it has been shown that treatment with THC has caused neither acute nor long-term cognitive deficits (Muller-Vahl et al., 2003). Our case study indicates that there seem to be beneficial effects on psychomotor functions related to driving performance under treatment with THC. To highlight this topic, further studies on Tourette's driving under THC-treatment are needed.(Author/publisher)
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