In recent decades there has been increased interest in the benefits of marijuana in the treatment of a multitude of conditions. Marijuana is advocated by many for the treatment of chronic inflammatory pain, cancer pain, nerve pain, nausea, decreased appetite, muscle spasm in multiple sclerosis, epilepsy, anxiety, insomnia, depression, glaucoma, opioid dependence, and even as a treatment for cancer.
Discussion of the beneficial properties of marijuana has been subjected to biases from enthusiastic supporters and from detractors. But what is the science?
The beneficial effects of marijuana are primarily related to chemical compounds called cannabinoids. The most discussed cannabinoids are THC—an abbreviation for tetrahydrocannabinol, and CBD oil—an abbreviation for cannabidiol. THC is the chemical that provides the intoxicating “high” when it attaches to receptors in our brains. CBD oil does not cause this euphoria and has been effective in the treatment of some rare forms of childhood epilepsy.
Previously the cannabis plant was thought to have less than a dozen different cannabinoids. Currently, over 100 different cannabinoids have been identified in different strains of marijuana. It also turns out that our bodies make types of cannabinoids, called endogenous cannabinoids, or, endocannabinoids. And cannabinoid receptors have been identified in our bodies. When cannabinoids attach to these receptors, a variety of effects are triggered.
The tremendous success of modern medicine is founded on the scientific method. Specifically, this means an emphasis on providing solid evidence that treatments are effective. The gold standard of evidence is the randomized, controlled, double-blind clinical trial. A double-blind trial compares treatments with neither the researcher nor the patient knowing which treatment is being given. Hundreds of clinical studies on the use of marijuana have been published. Many of these trials have small numbers of patients, are not blinded and have biases.
For example, a drug called Sativex (nabiximols) which combines two major cannabinoids, THC and CBD, in an oral spray was initially approved in Great Britain in 2010 for use in managing muscle spasticity in patients with multiple sclerosis. It has also received approval in Canada both for use in patients with multiple sclerosis and for patients with cancer pain. When larger double-blind clinical trials were performed as a step toward FDA approval in the United States, Sativex was shown to reduce cancer pain and muscle spasm; however, it was no more effective than placebo (pretend medicine). FDA approval of Sativex may occur in the future but, based on current evidence, it is not currently available in the United States.
One place for consumers to look for evidence-based reviews on cannabis and other medications is in the Cochrane Library. This is a non-profit organization which provides health information. This may be accessed for free at www.cochrane.org
Cochrane published a review of the medical literature on cannabis for the management of nerve (neuropathic) pain in March 2018. They looked at 16 studies which examined both medical cannabinoid products and marijuana and which comprised 1,750 patients. While there is some evidence that patients experienced relief from nerve pain with cannabis products, Cochrane concluded that there is a lack of good evidence. So, it is difficult to know how effective cannabis is for nerve pain.
There is evidence that cannabinoids may be useful in the management of nausea. However, we do not have evidence that marijuana products are as effective as currently used anti-nausea medications.
Marijuana has also been discussed as a treatment for cancer. Indeed, in the laboratory cancer cells have been killed by cannabinoids. A drug can kill cancer in a lab, however, and have no effect in a living person. There are no human studies to indicate that cannabinoids are useful as a treatment for cancer.
The U.S. government labeled marijuana as a Class 1 Controlled Substance in 1942 and, despite the recommendations of federal commissions dating back to the 1970s to change this designation, this current classification persists. The Class 1 designation is for drugs that are deemed unsafe with no currently accepted medical use. However, marijuana does have medicinal benefits and its safety and risks for abuse are much lower than drugs like opioids or benzodiazepines (alprazolam, diazepam, etc.) No one stops breathing from a massive overdose of marijuana, for example; however, respiratory arrest from a massive overdose of opioids is common. Marijuana does have risks. It impairs memory, judgement, and motor coordination.
As of June 2018, 29 states and D.C. have made medical marijuana legal. Of these 29 states, 9 states along with D.C. have made marijuana legal for recreational purposes. Medical marijuana is not legal in Virginia.
There are currently two FDA approved—and therefore legal in all 50 states—cannabinoid products. Marinol and Syndros are brand names for dronabinol which is a synthetic THC. It comes in capsules and liquid. Cesamet is the brand name for nabilone, which is also a manufactured cannabinoid, synthesized in the laboratory (rather than derived from the marijuana plant.) These medicines are prescribed for nausea and as appetite stimulants. They are sometimes prescribed “off-label,” which means they are sometimes prescribed for conditions for which they have not been specifically approved, for help with pain management. Some patients feel helped by these medications. Again, the evidence we have suggests that
they are mildly effective. They are less effective than other medicines available to treat these symptoms.
In June 2018, the FDA did finally grant approval to Epidiolex, a brand name cannabidiol (CBD oil) for use in patients with two rare and severe forms of epilepsy, Lennox-Gastaut syndrome and Dravet syndrome. Epidiolex is expected to be available in the U.S at the end of 2018. This will be the first medicine approved by the FDA actually derived from the marijuana plant.
Federal laws would take precedence over state laws if the federal authorities chose to intervene. And federal law states that marijuana is illegal. However, the U.S. government has not overstepped state jurisdiction.
District of Columbia