Dystonia is a neurological movement disorder characterized by abnormal muscle tension and involuntary, painful muscle contractions. It is the third most common movement disorder after Parkinson's disease and tremor, affecting more than 300,000 people in North America.
A small number of case reports and preclinical studies investigating the use of cannabis and cannabinoids for symptoms of dystonia are referenced in the recent scientific literature. A 2002 case study published in the July issue of the The Journal of Pain and Symptom Management reported improved symptoms of dystonia after smoking cannabis in a 42-year-old chronic pain patient. Investigators reported that subject’s subjective pain score fell from 9 to zero (on a zero-to-10 visual analog scale) following cannabis inhalation, and that the subject did not require any additional analgesic medication for the following 48 hours. "No other treatment intervention to date had resulted in such dramatic overall improvement in [the patient's] condition," investigators concluded.
A second case study reporting “significant clinical improvement” following cannabis inhalation in a single twenty five year old patient with generalized dystonia due to Wilson’s disease was documented by an Argentinian research team in the August 2004 issue of the journal Movement Disorders.
Also in 2004, a German research team at the Hannover Medical School reported successful treatment of musician’s dystonia in a thirty eight year-old professional pianist following administration of (5 mg of THC) in a placebo-controlled single-dose trial. Investigators reported “clear improvement of motor control” in the subject’s affected hand, and noted, “[Two] hours after THC intake, the patient was able to play technically demanding literature, which had not been possible before treatment.” Prior to cannabinoid treatment, the subject had been unresponsive to standard medications and was no longer performing publicly. “The results provide evidence that … THC intake … significantly improves [symptoms of] focal dystonia,” investigators concluded.
By contrast, a 2002 randomized, placebo-controlled study investigating the use of the synthetic oral cannabinoid naboline (Cesamet) in fifteen patients afflicted with generalized and segmental primary dystonia did not show a significant reduction in dystonic symptoms. Investigators speculated that this result may have been dose-related, and that administration of a higher dosage may have yielded a different outcome.
At least one recent preclinical trial indicates that both synthetic cannabinoids as well as high doses of the natural non-psychoactive cannabinoid cannabidiol (CBD) could moderate the disease progression of dystonia in animals. Limited references regarding the use of cannabinoids for dystonia in humans and animals in the 1980s and the 1990s also appear in the scientific literature. It would appear that additional, larger clinical trials are warranted to investigate the use of cannabis and cannabinoids for this indication.
 Chatterjee et al. 2002. A dramatic response to inhaled cannabis in a woman with central thalamic pain and dystonia. The Journal of Pain and Symptom Management 24: 4-6.
 Roca et al. 2004. Cannabis sativa and dystonia secondary to Wilson’s disease. Movement Disorders 20: 113-115.
 Jabusch et al. 2004. Delta-9-tetrahydrocannabinol improves motor control in a patient with musician’s dystonia (PDF). Movement Disorders 19: 990-991.
 Fox et al. 2002. Randomised, double-blind, placebo-controlled trial to assess the potential of cannabinoid receptor stimulation in the treatment of dystonia. Movement Disorders 17: 145-149.
 Richter et al. 2002. Effects of pharmacological manipulations of cannabinoid receptors on severe dystonia in a genetic model of paroxysmal dyskinesia. European Journal of Pharmacology 454: 145-151.
 Consroe et al. 1986. Open label evaluation of cannabidiol in dystonic movement disorders. International Journal of Neuroscience 30: 277-282.
 Richter et al. 1994. (+)-WIN 55212-2, a novel cannabinoid agonist, exerts antidystonic effects in mutant dystonic hamsters. European Journal of Pharmacology 264: 371-377.