Cannabinoids and Movement Disorders: Promising Signals
Movement disorders affect the brain’s control of movement and can cause excessive, reduced, or poorly coordinated activity. Symptoms may include tremor, stiffness, involuntary muscle contractions, tics, jerky movements, impaired balance, speech difficulties, and pain. Conditions associated with these symptoms include Parkinson’s disease, Huntington’s disease, Tourette syndrome, multiple sclerosis, dystonia, and various forms of ataxia.
The causes vary widely. Some disorders are inherited, while others result from stroke, infection, medication side effects, toxins, metabolic problems, or damage to the brain and nervous system. In some cases, no clear cause can be identified. Dystonia, for example, involves involuntary muscle contractions that may produce twisting movements, unusual postures, tremor, and pain.
How are movement disorders treated?
Treatment depends on the specific diagnosis, the symptoms involved, and their severity. Options may include physical, occupational, or speech therapy; medications; botulinum toxin injections for some forms of dystonia; and, in selected cases, surgery such as deep brain stimulation. These approaches generally aim to control symptoms and improve daily functioning rather than cure the underlying disorder.
What does the research say about cannabis?
Cannabis-based medicines have been investigated for symptoms associated with Parkinson’s disease, Huntington’s disease, Tourette syndrome, dystonia, and other movement disorders. The 2017 systematic review of randomized controlled trials cited in the earlier version of this article identified some positive findings involving Tourette syndrome, Huntington’s disease, and Parkinson’s-related dyskinesia. However, the studies were generally small and had important methodological limitations, so the review concluded that their results were not sufficient to establish effectiveness.
Subsequent evidence has remained mixed. A 2022 systematic review of randomized controlled trials found no consistent improvement in Parkinson’s motor symptoms. One small trial suggested that nabilone might reduce levodopa-induced dyskinesia, while other studies did not show a clear benefit. Some trials reported improvements in anxiety, sleep, or quality of life, but these outcomes are different from demonstrating better motor control. Studies of Tourette syndrome found possible reductions in tics, and one of several Huntington’s disease trials reported symptom relief. No reliable reduction in dystonia was demonstrated.
These findings are consistent with the National Academies’ review of cannabis and cannabinoids, which concluded that evidence was insufficient to determine whether cannabinoids effectively treat Parkinson’s motor symptoms or levodopa-induced dyskinesia. The review also emphasized that results from small, uncontrolled, or short-term studies should not be interpreted as proof that cannabis treats or slows a neurological disease.
It is also important to distinguish between regulated cannabinoid medicines and products sold as medical or recreational cannabis. Preparations can differ substantially in their concentrations of tetrahydrocannabinol (THC), cannabidiol (CBD), dose, route of administration, and purity. Cannabis may also cause adverse effects, including dizziness, sedation, impaired coordination, cognitive changes, and psychiatric symptoms. These risks may be particularly important for people who already have balance, movement, or cognitive problems.
Conclusion
Cannabinoids remain an area of interest in movement-disorder research, but current evidence does not support describing medical cannabis as a broadly established treatment. Some small studies suggest potential benefits for selected symptoms—particularly tics, anxiety, sleep problems, or possibly certain types of dyskinesia—but findings are inconsistent and do not establish long-term effectiveness or safety.
Anyone considering a cannabis-based product should discuss it with a qualified clinician, especially if they take other medications or have a history of falls, cognitive impairment, psychosis, or heart disease. Larger, well-designed clinical trials are still needed to determine which cannabinoid preparations, if any, are useful for specific movement-disorder symptoms.
