It’s now legal to use marijuana to treat certain medical conditions in 25 states, but the Food and Drug Administration has still not approved the marijuana plant as a treatment for any disease or health issue. That’s because there haven’t been enough large studies of the drug to show that its benefits outweigh the risks in patients who use it, said the National Institute on Drug Abuse (NIDA). And in order to gain approval, researchers also need show that marijuana is safer or more effective than existing treatments for certain conditions.
Nevertheless, scientists have good reason to think that the marijuana plant could be useful in treating a number of medical conditions. The active ingredient in marijuana, delta-9-tetrahydrocannabinol (THC), has been shown to increases appetite and reduces nausea. Another chemical in marijuana, cannabidiol (CBD), may decrease pain and inflammation and help with muscle-control problems, according to NIDA. Both THC and CBD belong to a group of chemicals called cannabinoids.
Live Science has rounded up the promising evidence that medical marijuana may help people with certain conditions. Here’s what we found.
Earlier this month, the United States Supreme Court ruled that federal drug laws trump policies in ten states that permit medicinal marijuana use.
The decree reignites a smoldering debate among scientists, activists, and lawmakers about how to leverage marijuana’s medical benefits while minimizing its potential for abuse.
Known by the scientific name Cannabis sativa, marijuana is an annual herb closely related to the hops used in beer brewing.
Cannabis has been “used since antiquity for both herbal medication and intoxication,” according to a 1999 study commissioned by the Institute of Medicine (IOM), a Washington, D.C.-based component of the National Academy of Sciences.
“There is scientific evidence that [marijuana] helps with pain relief and nausea and vomiting from chemotherapy, for example, in terminal cancer patients,” said John A. Benson, Jr., a principal investigator of the IOM study and a professor of internal medicine at the University of Nebraska Medical Center.
In addition, some HIV/AIDS patients suffering from decreased appetites use marijuana to “get the munchies,” another oft-noted effect of the drug.
Roger Pertwee, a professor of neuropharmacology at the University of Aberdeen’s Institute of Medical Sciences in Scotland, noted that “cannabis contains lots of different chemicals called cannabinoids.” The most active chemical is delta-9-tetrahydrocannabinol, or THC.
THC binds to specific receptors in the human brain to create the euphoric high associated with smoking pot.
Indica and Sativa Strains
Cannabis is divided into two main types, indica (e.g.: Bubble Kush) and sativa (e.g.: Alaskan Thunderfuck). Indica is more known for its broad leaves, heavy body high, squat profile and soporific effects; it is often seen as a good choice for evening or nighttime use. Sativa, on the other hand, is more energetic, with thin leaves, a tall, gangly profile, and a more cerebral high. It is often a go-to for morning or daytime use.
Beyond indica and sativa, the plant has hundreds of distinct “strains,” each exhibiting their own set of characteristics. But you can also find strains classified as hybrid (e.g: Gorilla Cookies) which have a balanced combination of both indica and sativa’s characteristics.
The variability of strains is almost endless. This is due not just to various combinations of physical characteristics and cannabinoid levels, though those play definite roles. It is also due to various combinations of terpenes and flavonoids. These are natural aromatic compounds which can influence the intensity and nature of the effects.
Strains first became a factor in cannabis culture in the late 1960s. “Brand names” such as Panama Red and Acapulco Gold quickly gained fame. This wasn’t just for their memorable appearance, but also for their potency. As the 1970s unfurled, strains such as Thai Stick, Santa Marta Gold, Colombian Red Bud, and Michoacan became legendary. And with the rise of Dutch breeding in the 1980s, such genetic masterpieces as Northern Lights #1, Big Bud, and Skunk #1 carved out their places in the pot pantheon.
As cannabis breeding became an increasingly sophisticated effort, more and more “hybrid” strains combined the qualities of indica and sativa strains. This has been such a popular practice that the genetics of “pure” indicas such as L.A. Confidential and The Hog and “pure” sativas such as Durban Poison and Dutch Passion have become cherished heirlooms.
Modern-day favorites like Girl Scout Cookies, Gorilla Glue #4, Granddaddy Purple, Blue Dream, Sour Diesel, OG Kush, and White Widow have taken cannabis breeding to its lofty current level. Top-shelf iterations of these strains are often top 20 percent, and even 25 percent THC.
Pain in patients with multiple sclerosis
Marijuana may reduce feelings of burning, tingling or numbness, as well as pain from muscle spasms, in patients with multiple sclerosis (MS), according to a 2014 review study. The study found strong evidence that oral cannabis extract, which is a pill made from CBD, or a combination of THC and CBD, can help with these symptoms, the researchers said. However, not enough studies have been conducted to determine whether smoking marijuana helps with symptoms of MS, the review found.
Chronic pain in patients with cancer
A small study of 36 cancer patients found that 10 milligrams of THC produced pain-relieving effects comparable to those of taking 60 mg of the opiate codeine. Another study of a drug called nabiximols (brand name Sativex), which is a “marijuana mouth spray” that contains both THC and CBD, found that low and medium doses of the spray had better pain-relieving effects than a placebo. This result was found in cancer patients with pain who had not been helped by taking opioid drugs. However, very few studies have looked at the benefits of smoked marijuana for treating pain in cancer patients.
A 2010 study looked at 23 patients who had neuropathic pain (which is pain caused by damage to nerves) after trauma or surgery. The study found that those who smoked marijuana reported they had less pain and slept better than those who were given a placebo. A 2013 study of 39 people found that vaporized cannabis reduced neuropathic pain in patients who had not been helped by other treatments.
A 2015 study examined whether a daily dose of cannabis extract could help people with severe epilepsy who had not been helped by previous treatments. The study included 137 people who ranged in age from toddlers to adults. It found that the number of seizures that participants experienced declined by 54 percent over a 12-week period. Still, the study did not include a “control group” of participants who didn’t take the drug, so it’s not clear if the results were due to a placebo effect, the researchers said.