AAN: Still Too Early to Green-Light Medical Marijuana

Pauline Anderson

December 23, 2014

The American Academy of Neurology (AAN) doesn't advocate for the legalization of medical marijuana to treat neurologic conditions because of the lack of evidence, but it wants researchers to have easier access to these products for study purposes, according to a new position statement.

Research to determine the benefits and safety of marijuana-based products "is of paramount importance" when these products are used in patients with underlying neurologic disorders, or in children whose developing brains may be more vulnerable to the toxic effects of marijuana, notes the document, drafted by a team led by Anup Patel, MD, pediatric neurologist, Nationwide Children's Hospital, Columbus, Ohio.

The new position statement was published online December 17 in Neurology.

State legislation that promotes marijuana-based products as treatment options for various neurologic disorders is not supported by high-level medical research, said the statement. There's concern not only about the safety of these products, especially for long-term use in patients with disorders of the nervous system, but also about the interaction of these compounds with prescription medications.

While the Academy recognizes that these agents may have potential in the field of neurology, the document stressed that it's inappropriate to extrapolate the results of trials of standardized preparations to other, nonstandardized, nonregulated cannabis products that may be commercially available in the United States. It also noted that most currently available marijuana products are not regulated by any agency and may not contain the products mentioned by labeling.

"Quality control is therefore impossible, raising further safety questions. Each product and formulation of cannabis should demonstrate safety and effectiveness via scientific study similar to the process required by the Food and Drug Administration (FDA)," the authors write.

The federal government classifies marijuana products as a Schedule I drug, defined as having no accepted medical use and a high potential for abuse. State law does not protect prescribers of such products from federal prosecution unless they obtain a Schedule I license from the Drug Enforcement Administration (DEA). Some states have enacted bills allowing providers to prescribe marijuana-based products, but only if they contain nonpsychoactive ingredients.

Reduce Barriers

"Reclassification by the DEA will expedite future research on marijuana-based products as it will reduce barriers to study participation by investigators who do not possess a schedule I license," said the statement.

Marijuana is derived from the Cannabis sativa plant, which contains over 60 pharmacologically active compounds called cannabinoids. Delta-9-tetrahydrocannabinol (THC) is the plant's major psychoactive compound. Other cannabinoid compounds, such as cannabinol and cannabidiol, are not believed to have psychoactive properties.

Earlier this year, the AAN issued an evidence-based guideline that supported the use of specific oral and oromucosal forms of cannabis to improve some symptoms in patients with multiple sclerosis.

A subsequent AAN systematic review of medical marijuana for neurologic disorders concluded that oral cannabis extracts are probably ineffective for treating levodopa-induced abnormal involuntary movements in Parkinson's disease, but it did not find evidence for or against the use of oral cannabinoids for several other conditions.

Neurology. Published online December 17, 2014. Abstract


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