23 health benefits of marijuana

By: Kevin Loria 
Mar 7, 2018

States around the country — 29 of them, plus Washington DC — have legalized medical marijuana. 
The American public largely supports the legalization of medical marijuana. At least 84% of the public believes the drug should be legal for medical uses, and recreational pot usage is less controversial than ever, with at least 61% of Americans in support.

Even though some medical benefits of smoking pot may be overstated by advocates of marijuana legalization, recent research has demonstrated that there are legitimate medical uses for marijuana and strong reasons to continue studying the drug's medicinal uses.

Even the NIH's National Institute on Drug Abuse lists medical uses for cannabis.

There are at least two active chemicals in marijuana that researchers think have medicinal applications. Those are cannabidiol (CBD) — which seems to impact the brain without a high— and tetrahydrocannabinol (THC) — which has pain relieving properties and is largely responsible for the high.

But scientists say that limitations on marijuana research mean we still have big questions about its medicinal properties. In addition to CBD and THC, there are another 400 or so chemical compounds, more than 60 of which are cannabinoids. Many of these could have medical uses. But without more research, we won't know how to best make use of those compounds.

More research would also shed light on the risks of marijuana. Even if there are legitimate uses for medicinal marijuana, that doesn't mean all use is harmless. Some research indicates that chronic, heavy users may have impaired memory, learning, and processing speed, especially if they started regularly using marijuana before age 16 or 17.

For some of the following medical benefits, there's good evidence. For others, there's reason to continue conducting research.

The best-supported medicinal use of marijuana is as a treatment for chronic pain.

A recent report by the National Academies of Sciences, Engineering, and Medicine said there was definitive evidence that cannabis or cannabinoids (which are found in the marijuana plant) can be an effective treatment for chronic pain.

The report said that is "by far the most common" reason people request medical marijuana.

There's also strong evidence medical cannabis can help with muscle spasms.

That same report said there's equally strong evidence marijuana can help with muscle spasms related to multiple sclerosis.

Other types of muscle spasms respond to marijuana as well. People use medical marijuana to treat diaphragm spasms that are untreatable by other, prescribed medications.

It doesn't seem to harm lung capacity, and may even improve it.

There's a fair amount of evidence that marijuana does no harm to the lungs, unless you also smoke tobacco. One study published in Journal of the American Medical Association found that not only does marijuana not impair lung function, it may even increase lung capacity.

Researchers looking for risk factors of heart disease tested the lung function of 5,115 young adults over the course of 20 years. Tobacco smokers lost lung function over time, but pot users actually showed an increase in lung capacity.

It's possible that the increased lung capacity may be due to taking a deep breaths while inhaling the drug and not from a therapeutic chemical in the drug.

The smokers in that study only toked up a few times a month, but a more recent survey of people who smoked pot daily for up to 20 years found no evidence that smoking pot harmed their lungs, either.

The National Academies report said there are good studies showing marijuana users are not more likely to have cancers associated with smoking.

It may be of some use in treating glaucoma, or it may be possible to derive a drug from marijuana for this use.

One of the most common reasons that states allow medical marijuana use is to treat and prevent the eye disease glaucoma, which increases pressure in the eyeball, damaging the optic nerve and causing loss of vision.

Marijuana decreases the pressure inside the eye, according to the National Eye Institute: "Studies in the early 1970s showed that marijuana, when smoked, lowered intraocular pressure (IOP) in people with normal pressure and those with glaucoma."

For now, the medical consensus is that marijuana only lowers IOP for a few hours, meaning there's not good evidence for it as a long term treatment right now. Researchers hope that perhaps a marijuana-based compound could be developed that lasts longer.

It may help control epileptic seizures.

Some studies have shown that cannabidiol (CBD), another major marijuana compound, seems to help people with treatment-resistant epilepsy.

A number of individuals have reported that marijuana is the only thing that helps control their or their children's seizures.

However, there haven't been many gold-standard, double-blind studies on the topic, so researchers say more data is needed before we know how effective marijuana is.

It also decreases the symptoms of a severe seizure disorder known as Dravet's Syndrome.

During the research for his documentary "Weed," Sanjay Gupta interviewed the Figi family, who treated their 5-year-old daughter using a medical marijuana strain high in cannabidiol and low in THC.

The Figi family's daughter, Charlotte, has Dravet Syndrome, which causes seizures and severe developmental delays.

According to the film, the drug decreased her seizures from 300 a week to just one every seven days. Forty other children in the state were using the same strain of marijuana to treat their seizures when the film was made — and it seemed to be working.

The doctors who recommended this treatment said the cannabidiol in the plant interacts with brain cells to quiet the excessive activity in the brain that causes these seizures.

Gupta notes, however, that a Florida hospital that specializes in the disorder, the American Academy of Pediatrics, and the Drug Enforcement agency don't endorse marijuana as a treatment for Dravet or other seizure disorders.

A chemical found in marijuana stops cancer from spreading, at least in cell cultures.

CBD may help prevent cancer from spreading, researchers at California Pacific Medical Center in San Francisco reported in 2007.

Other very preliminary studies on aggressive brain tumors in mice or cell cultures have shown that THC and CBD can slow or shrink tumors at the right dose, which is a strong reason to do more research.

One 2014 study found that marijuana can significantly slow the growth of the type of brain tumor associated with 80% of malignant brain cancer in people.

Still, these findings in cell cultures and animals don't necessarily mean the effect will translate to people — far more investigation is needed.