The extent to which marijuana is an effective medical treatment is a much-debated issue. Now, the American Academy of Neurology have produced a review of all available evidence on the use of marijuana to treat brain diseases. The Academy yesterday unveiled their findings at the AAN Annual Meeting in Philadelphia, PA - the world's largest gathering of neurologists.
"This review by the world's largest association for neurologists is intended to help neurologists and their patients understand the current research on medical marijuana for the treatment of certain brain diseases," says lead author Dr. Barbara S. Koppel, of New York Medical College and Fellow of the American Academy of Neurology (AAN).
"The AAN review also highlights the need for more high-quality studies of the long-term efficacy and safety of medical marijuana in the treatment of neurologic diseases," she adds.
Recently, the AAN published a new guideline on the use of marijuana pills and sprays in the treatment of multiple sclerosis (MS).
Writing in the AAN journal Neurology, a team of researchers described marijuana as being a beneficial treatment for MS, but emphasized that the side effects of the drug - including seizures, dizziness, thinking and memory problems, and depression - should be taken into consideration when prescribing.
The AAN suggest that marijuana should only be prescribed as a medical treatment when standard treatment has been ineffective.
The new AAN study repeats the assertion that marijuana can relieve some MS symptoms, including spasticity and related pain, and overactive bladder.
However, the AAN researchers conclude that marijuana is not helpful in treating levodopa-induced Parkinson's movements. Furthermore, there is not enough evidence to say whether marijuana is a successful treatment for Huntington's disease, Tourette syndrome, cervical dystonia or epileptic seizures.
The studies examined by the review mostly looked at the pill and oral spray versions of medical marijuana. Two of the studies did assess the medical benefits of smoked marijuana on MS symptoms but were unable to conclude whether smoked marijuana was an effective treatment.
In addition to the side effects listed in the AAN's MS guideline, the studies in the review reported nausea, increased weakness, behavioral or mood changes, suicidal thoughts, hallucinations, fainting symptoms, fatigue and feelings of intoxication as adverse effects.
The AAN calculate that about 1 in every 100 patients using marijuana as a medical treatment is at risk of serious psychological effects.
These side effects create safety concerns for using the drug as an MS treatment, because patients who have MS are at an increased risk for depression or suicide. As Dr. Koppel explains:
"It's important to note that medical marijuana can worsen thinking and memory problems, and this is a concern since many people with MS suffer from these problems already due to the disease itself."
The Academy suggest that marijuana should only be prescribed as a medical treatment when standard treatment has been ineffective.
Last year, Medical News Today reported on a study by researchers from the Feinburg School of Medicine at Northwestern University in Illinois, which linked marijuana use to schizophrenia-type changes in the brain.
Another study, published in the journal Neuropsychopharmacology, also found that regular recreational use of marijuana in adolescence can result in damage to brain function and increased risk of psychiatric problems, such as schizophrenia. The researchers behind that study commented: "There is likely a genetic susceptibility, and then you add marijuana during adolescence and it becomes the trigger."