Abstract
Objective: To determine the efficacy of medical marijuana in several neurologic conditions.
Methods: We performed a systematic review of medical marijuana (1948–November 2013) to address treatment of symptoms of multiple sclerosis (MS), epilepsy, and movement disorders. We graded the studies according to the American Academy of Neurology classification scheme for therapeutic articles.
Results: Thirty-four studies met inclusion criteria; 8 were rated as Class I.
Conclusions: The following were studied in patients with MS: (1) Spasticity: oral cannabis extract (OCE) is effective, and nabiximols and tetrahydrocannabinol (THC) are probably effective, for reducing patient-centered measures; it is possible both OCE and THC are effective for reducing both patient-centered and objective measures at 1 year. (2) Central pain or painful spasms (including spasticity-related pain, excluding neuropathic pain): OCE is effective; THC and nabiximols are probably effective. (3) Urinary dysfunction: nabiximols is probably effective for reducing bladder voids/day; THC and OCE are probably ineffective for reducing bladder complaints. (4) Tremor: THC and OCE are probably ineffective; nabiximols is possibly ineffective. (5) Other neurologic conditions: OCE is probably ineffective for treating levodopa-induced dyskinesias in patients with Parkinson disease. Oral cannabinoids are of unknown efficacy in non–chorea-related symptoms of Huntington disease, Tourette syndrome, cervical dystonia, and epilepsy. The risks and benefits of medical marijuana should be weighed carefully. Risk of serious adverse psychopathologic effects was nearly 1%. Comparative effectiveness of medical marijuana vs other therapies is unknown for these indications.
GLOSSARY
- AAN=
- American Academy of Neurology;
- AE=
- adverse effect;
- CBD=
- cannabidiol;
- CI=
- confidence interval;
- CRS=
- category rating scale;
- HD=
- Huntington disease;
- ITT=
- intention-to-treat;
- MS=
- multiple sclerosis;
- NRS=
- numeric rating score;
- OCE=
- oral cannabis extract;
- THC=
- Δ-9-tetrahydrocannabinol;
- UHDRS=
- Unified Huntington's Disease Rating Scale;
- UPDRS=
- Unified Parkinson's Disease Rating Scale;
- VAS=
- visual analog scale
Footnotes
Approved by the Guideline Development Subcommittee on January 12, 2013; by the Practice Committee on August 19, 2013; and by the AANI Board of Directors on February 22, 2014.
This systematic review was endorsed by the American Autonomic Society on December 12, 2012; by the American Epilepsy Society on January 15, 2013; and by the International Rett Syndrome Foundation on March 12, 2014.
Go to Neurology.org for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.
Supplemental data at Neurology.org
- Received September 26, 2013.
- Accepted in final form February 19, 2014.
- © 2014 American Academy of Neurology
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