Neurologists say jury still out on medical marijuana's use for brain disorders

(HealthDay)—It's too soon to tell whether medical marijuana can help treat neurological disorders such as epilepsy, multiple sclerosis and Parkinson's disease, the American Academy of Neurology (AAN) said in a new position statement released Wednesday.

Marijuana may be useful in treating some illnesses of the brain and nervous system, but "there is not sufficient evidence to make any definitive conclusions regarding the effectiveness of marijuana-based products for many neurologic conditions," according to the statement.

To help settle the matter, the AAN statement called on the federal government to loosen its current regulations on marijuana research. These regulations likely restrict scientific research into medical pot's effectiveness and safety, the statement suggested.

Medical marijuana might be helpful for people with multiple sclerosis (MS), the AAN noted. It might reduce spasms, decrease pain and control urinary incontinence in people with MS, according to a review of studies the AAN published in April.

But the AAN statement said that the studies conducted so far do not provide enough evidence to support prescribing marijuana for neurological conditions, such as MS.

"They're not as robust as we need them to be," position statement author Dr. Anup Patel, a pediatric neurologist with Nationwide Children's Hospital in Columbus, Ohio, said of the studies conducted so far.

"There are not enough subjects and there's not good enough study design that we can say one way or another that this product would be beneficial and not harmful to our patients," Patel added.

The AAN believes that marijuana should be reclassified so that it's no longer a Schedule I drug. That classification means a drug has no currently accepted medical use and a high potential for abuse, the AAN statement said.

Researchers who want to explore marijuana's medical potential now must fill out reams of extra paperwork, obtain a special license, and adhere to strict storage requirements set forth by the U.S. Drug Enforcement Administration and the U.S. Food and Drug Administration, Patel said.

If federal regulators reclassified marijuana to a less-restrictive status, it would expand researchers' access to the drug. Reclassification would also pave the way for tests that could determine whether or not pot is an effective treatment, the statement said.

"We want this to be answered, like any other medical product, through good science and clinical trials," Patel said. "We in the neurological community are committed to performing those research trials, but it's very, very difficult to do so under current regulations."

Questions that more extensive trials could answer include:

• Whether THC, the intoxicating chemical in marijuana, would do more harm than good with long-term use. "You're taking a brain that's already not normal, and what effect these products might have on a non-normal brain isn't clear at this point," Patel said. Some studies have shown that long-term marijuana use may cause problems with memory, concentration and decision-making.
• How the lack of consistency in marijuana doses might affect the drug's usefulness. Levels of THC and other compounds vary widely between different pot harvests. This makes it difficult to determine effectiveness and to prescribe accurately.
• Whether research conducted on marijuana overseas is similar to treatment in the United States. Many cannabis preparations used in other countries—sprays, extracts and the like—are not available in the United States, which means the pot available here might not have the same effect, according to Patel.
• What effect marijuana might have on the still-developing brains of pediatric patients. Children may be more vulnerable to any toxic effects the drug might have.

The pro-marijuana group NORML disagreed with the AAN's assertion that there isn't enough scientific evidence to prove pot's beneficial effects.

"Empirical data regarding the long-term effects and relative safety of cannabis most certainly is available," said NORML Deputy Director Paul Armentano. "Unlike the case with most pharmaceuticals, for which we have often have sparse data regarding the drugs' long-term effects, humans have been consuming the plant therapeutically and socially for, quite literally, thousands of years—typically without significant risks to health."

However, NORML agreed that regulations should be loosened to allow for more clinical study of marijuana.

"Unfortunately, the ongoing politicization of cannabis as a Schedule I controlled substance continues to hinder opportunities and funding for the sort of gold-standard clinical research groups like the AAN typically rely upon," Armentano said.

"This situation will only change when cannabis is federally de-scheduled in a manner that fully allows clinical investigators access to the plant," he added.