President Trump recently loosened restrictions on medical marijuana, which millions of Americans are already using to treat chronic pain and other conditions.
Medical experts say they’re hopeful that the move will foster more research on the drug, which could reveal new therapeutic applications for cannabis and its compounds, such as cannabidiol, or CBD. But at the same time, they said, it may reinforce misconceptions about the safety and utility of the drug. Here’s what they want you to know about the drug’s risks and side effects, what it might help treat and where the research is lacking.
There are only a few science-backed uses.
The Food and Drug Administration has approved a handful of drugs that contain cannabis, cannabis components or similar synthetic products, which are prescribed to treat chemotherapy-induced nausea, a wasting syndrome related to AIDS and a type of seizure.
Beyond those, experts say, perhaps the strongest evidence so far is on the use of cannabis for pain relief. About 53 percent of people who say they use cannabis for health reasons say they do so to relieve pain, and most states allow medical marijuana use for that reason.
Doctors whose chronic pain patients use cannabis say that although it only moderately dampens pain, it appears to help people cope.
“Their actual pain intensity hasn’t changed very much, but their mood is better, they sleep better, their quality of life is better,” said Dr. Ali John Zarrabi, an internist and palliative care physician and researcher for the Winship Cancer Institute at Emory University.
Even so, medical societies such as the International Association for the Study of Pain recommend against cannabis as a go-to treatment, because the data is limited and there is a risk of side effects, including dizziness, drowsiness and nausea.
Evidence on many other health claims is scant.
States around the country have authorized medical marijuana, which is sold at dispensaries and online, for a wide range of health conditions. (Illinois has a list of 56, for example.) A few states allow medical use for any reason a doctor deems appropriate.
But there is little or no good evidence showing that it benefits many conditions that are on states’ qualifying lists, including post-traumatic stress disorder, Parkinson’s disease, glaucoma and A.L.S., according to Almut Gertrud Winterstein, director of the Consortium for Medical Marijuana Clinical Outcomes Research, a University of Florida initiative that supports and conducts research on the effects of medical marijuana on health conditions.
After pain, anxiety is the most common medicinal reason consumers cite for using cannabis. The American Psychiatric Association opposes the medical use of cannabis and says there is insufficient evidence it is effective for treating any psychiatric illness. The organization also says that there is a strong association between cannabis use and the onset and exacerbation of psychiatric disorders, especially among children, adolescents and young adults.
Another common use is to combat insomnia. Evidence that cannabis improves sleep is also limited, though, and sleep medicine societies discourage its use.
It’s more potent than you might realize.
Cannabis products available today have far greater concentrations of THC, the component of the plant that produces a high, than they did decades ago.
Although estimates of the increase in potency vary widely, National Institute on Drug Abuse analyses of illegal cannabis products found that the amount of THC in them quadrupled between 1995 and 2022. Cannabis concentrates sold in dispensaries may contain THC levels as high as 40 percent.
Experts say higher potency products are more likely to lead to cannabis use disorder, which is defined as an inability to stop using cannabis even when the drug is causing harm.
“There is a definite misconception that cannabis is not addictive,” said Dr. Smita Das, clinical professor of psychiatry and behavioral sciences at Stanford University School of Medicine.
“That may have been true years ago, when people were just rolling up joints the old fashioned way, with pieces of the dry flower,” Dr. Das said. But today’s more potent products can create a higher sense of euphoria. “When it starts leaving their system they crave it more, so next time, they may need more and use more,” she added.
It is hard to predict who will develop cannabis use disorder, which is estimated to affect as many as three in 10 people who use cannabis. “Cannabis is like alcohol. Many adults can drink responsibly, and others, it destroys their lives,” said Dr. Kevin Gray, professor of psychiatry and behavioral sciences at the Medical University of South Carolina.
Those at heightened risk include men; people who initiate use as teenagers; anyone with a parent or sibling who has a substance abuse disorder; and those who have a mental health condition like depression and use cannabis to self-medicate.
Canadian studies have tied cannabis use disorder to a higher risk of death, including from trauma, suicide and other causes.
If you use it, your doctor should know.
Like any other drug, cannabis comes with side effects, and can interact dangerously with other prescription medications, particularly blood thinners, anti-depressants and pain medications.
That’s one reason it’s worth talking to your doctor if you’re using cannabis. Another is that your doctor may need to watch for potential short or long-term effects you may experience.
Most of the studies on cannabis and health don’t show cause and effect. However, those studies have linked cannabis use to an increased risk of cardiovascular disease, strokes and heart attacks, even among younger adults. The risk seems to start with weekly use and increases with the frequency of use and THC level. Chronic use has been associated with an increased risk of schizophrenia and other psychotic disorders, with the most frequent users at the highest risk.
Long-term smoking of the drug has also been linked to worsening respiratory symptoms and more frequent episodes of bronchitis and wheezing.
Additionally, some people who are heavy cannabis users may develop symptoms of cannabinoid hyperemesis syndrome, which causes stomach aches, nausea and vomiting. One survey found that just under one in five longtime daily users reported symptoms of the syndrome.
It’s hard to know what dose you’re getting.
Doctors have also shied away from recommending cannabis because of the variation in formulations, said Dr. Samer Narouze, chief of the pain medicine division at University Hospitals in Cleveland.
“The dispensary gives them whatever they have on their shelves, and you don’t know how many milligrams they’re getting,” Dr. Narouze said. “You recommend a low THC concentration or a high THC concentration, but you don’t know if this is what they’re really getting.”
The studies that found cannabis helped with pain were carried out 10 or 20 years ago with low THC products that were very different from what is available now, and the concern is that high THC products may have more adverse effects, Dr. Winterstein said. The participants in older studies were also mostly recreational users, not elderly patients who are at greater risk of falls or other side effects.
It’s best for pregnant women and adolescents to avoid it.
Certain groups are particularly vulnerable to harmful outcomes, including pregnant women, some of whom have used cannabis to cope with nausea and vomiting.
Last year, the American College of Obstetricians and Gynecologists put out new guidance urging pregnant and breastfeeding women to refrain from using the drug. The group noted it has been linked to poor birth outcomes, including low birth weight and, potentially, stillbirth. It has also been linked to neurocognitive and behavioral problems in children, the group said.
“Whether you eat it or smoke it, it gets in the body, it crosses over to the placenta, and it can get into the baby,” said Dr. Melissa Russo, a maternal-fetal medicine physician and one of the authors of that guidance.
Adolescents are also uniquely vulnerable because their brains are still developing, Dr. Gray said. He advises teens to postpone use for as long as possible.
“Regular cannabis use impairs cognition,” Dr. Gray said. “While we think it can recover once one ceases use, one of the main goals in adolescence is learning and advancing one’s education, and cannabis interferes with that.”
Adolescents may be more susceptible than adults to becoming dependent on cannabis, he added. A Canadian study also found they were at significantly heightened risk of psychosis when compared with adolescents who didn’t use cannabis. That heightened risk was not found in young adults who used cannabis.
Roni Caryn Rabin is a Times health reporter focused on maternal and child health, racial and economic disparities in health care, and the influence of money on medicine.
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