This November four states—Arkansas, Florida, Montana, and North Dakota—will vote on legalizing medical marijuana. Here are some things you should know to navigate the public debate about the legalization of cannabis for medicinal purposes.

What is medical marijuana?

FlickrThe terms marijuana and cannabis refer to all parts of the plant Cannabis sativa L., whether growing or not; the seeds thereof; the resin extracted from any part of such plant; and every compound, manufacture, salt, derivative, mixture, or preparation of such plant, its seeds or resin.

The term “medical marijuana” (or medical cannabis) refers to the use of the unprocessed plant or its basic extracts to treat a disease or symptom. However, the use of the term “medical marijuana” is controversial since the U.S. Food and Drug Administration (FDA) has not recognized or approved the marijuana plant as medicine, and its efficacy for medicinal use is disputed.  

Is medical marijuana a form of “medication”?

No. A medication is a substance used in treating disease or relieving pain. The term medical marijuana refers to treating a disease or symptom with the whole unprocessed marijuana plant or its basic extracts. Neither the unprocessed plant nor its extracts is medication, though each may contain substances (specifically cannabinoids) that do have medicinal value.

As Dr. Greg Bledsoe, the surgeon general of Arkansas, explains,

Unequivocally, the plant is not medicine. The plant cannot go through the FDA-approval process because you don’t know the dose, you don’t the other compounds that are in there, you can’t control the amount you are giving to patients. So a plant can never be FDA-approved. . . The compounds are so potent in the marijuana plant that if you do it with anything less than an FDA -pproval process with strict confines on it, it could be dangerous to people.

If the plant (cannabis) contains medicine, why shouldn’t it be considered a form of medication?

To understand why there is a distinction, it helps to compare cannabis to other plants that contain compounds of medicinal value. As Dr. Bledsoe says,

One of the best drugs we have for malaria still today is a drug that was developed from a tree in Peru. We get the tree bark from this tree and isolate a compound from it and make the drug quinine. Quinine is used all over the world to fight malaria. That’s the correct way of doing this. We don’t go around prescribing tree bark to patients who have malaria. We proscribe the compound within the tree bark. It’s the same thing with marijuana. We take the plant, isolate the compounds that have therapeutic value, study those and put them through the FDA approval process, and offer those to patients.

What compounds in marijuana have medicinal use?

The compounds that may have medicinal uses are cannabinoids, a class of chemical compounds that acts on cannabinoid receptors in cells that represses neurotransmitter release in the brain. The marijuana plant contains more than 100 cannabinoids. Currently, the two main cannabinoids from the marijuana plant that are of medical interest are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD).

According to the National Institute on Drug Abuse, THC increases appetite and reduces nausea and may also decrease pain, inflammation (swelling and redness), and muscle control problems. CBD is a cannabinoid that does not affect the mind or behavior. It may be useful in reducing pain and inflammation, controlling epileptic seizures, and possibly even treating mental illness and addictions.

The National Institutes of Health and other researchers are exploring the possible uses of THC, CBD, and other cannabinoids for medical treatment.

What FDA-approved medications contain cannabinoids?

The FDA has approved two drugs, dronabinol and nabilone, which contain THC. These drugs treat nausea caused by chemotherapy and increase appetite in patients with extreme weight loss caused by AIDS.

The United Kingdom, Canada, and several European countries, notes the National Institute on Drug Abuse, have approved nabiximols (Sativex®), a mouth spray containing THC and CBD. It treats muscle control problems caused by multiple sclerosis (MS). (Clinical trials are being conducted for use in treating cancer pain.) And although it has not yet undergone clinical trials, scientists have recently created Epidiolex, a CBD-based liquid drug to treat certain forms of childhood epilepsy.

Does medical marijuana help treat glaucoma?

Marijuana is not recommended as a treatment for glaucoma, according to the American Academy of Ophthalmology (AAO).

Glaucoma is an eye condition in which the optic nerve becomes progressively damaged. Over a period of time the condition can lead to reduced peripheral vision and even to blindness. A primary cause of optic nerve damage in glaucoma is higher-than-normal pressure within the eye, known as intraocular pressure or IOP.

Currently, the only way to control glaucoma and prevent vision loss, says the AAO, is to lower IOP levels. Some research has shown that ingesting marijuana does lower IOP for a short period of time—about three or four hours. Because glaucoma needs to be treated 24 hours a day, notes the AAO, a patient with glaucoma would “need to smoke marijuana six to eight times a day around the clock to receive the benefit of a consistently lowered IOP.” However, marijuana not only lowers IOP, but also lowers blood pressure throughout the body—including to the optic nerve, effectively canceling out the benefit of a lowered IOP.

Can a doctor write a prescription for medical marijuana?

No. According to the Journal of the American Medical Association,

Under federal law, marijuana has no currently accepted medical use and has a high potential for abuse. For these reasons, doctors cannot prescribe marijuana. In a state that allows the use of marijuana to treat medical conditions, however, a doctor may be able to certify its use. Your state may require you to apply for a state-issued identification card to use medical marijuana.

Do medical association support the use of medical marijuana?

The general consensus is that medical associations do not support the use of the cannabis plant as medicine. The American Medical Association (AMA) states that they do not endorse “state-based medical cannabis programs, the legalization of marijuana, or that scientific evidence on the therapeutic use of cannabis meets the current standards for a prescription drug product.” The American Psychiatric Association (APA) states that, “There is no current scientific evidence that marijuana is in any way beneficial for the treatment of any psychiatric disorder. In contrast, current evidence supports, at minimum, a strong association of cannabis use with the onset of psychiatric disorders.” The American Society of Addiction Medicine (ASAM) says, “Given the uncertain evidence to support the safety and efficacy of cannabis and cannabinoid-products in the treatment of medical conditions, ASAM and a number of other professional medical societies have advised that all cannabis-based medicinal products, like all other medicinal products, should be approved by FDA.”

Where is the use of medical marijuana currently legal?

The following 25 states (and the District of Columbia) have legalized medical marijuana: Alaska, Arizona, California, Colorado, Connecticut, Delaware, Hawaii, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, Montana, Nevada, New Hampshire, New Jersey, New Mexico, New York, Ohio, Oregon, Pennsylvania, Rhode Island, Vermont, and Washington.

Addendum: For more on this topic, watch this video by Dr. Greg Bledsoe, the surgeon general of Arkansas.

See also: Is Recreational Marijuana Use a Sin?