- A recent study found that 80 percent of medical cannabis users substitute it for prescription pain medications such as opioids.
- Of these, 88 percent reported that cannabis had helped their pain a lot or a little.
- Currently marijuana is legal in 11 states and Washington, D.C., and decriminalized in another 15 states.
This month Hawaii became the 15th U.S. state to decriminalize marijuana. An additional 11 states and Washington, D.C. have already legalized marijuana.
But for many people with chronic pain, these legal shifts have provided them with an alternative way to manage their pain, with some people using cannabis in place of prescription medications like opioids.
Hawaii’s new law allows people to possess up to 3 grams of cannabis without danger of jail time, although they can still be fined $130. Repeat offenses and possession of larger amounts, though, can still result in more severe sentences.
Increasingly, research shows that many people with chronic pain are turning to cannabis for relief.
A study published earlier this month in The Journal of Pain found that about 80 percent of 1,321 medical cannabis users reported substituting it for prescription pain medications — opioids or benzodiazepines such as Xanax or Valium.
The main reasons they gave for using cannabis is because it had fewer side effects and helped them manage their pain better.
In fact, 88 percent of people substituting cannabis reported that their pain had improved a lot or a little.
Although most of the research in this area focuses on medical cannabis users, Michelle St. Pierre, a PhD student in clinical psychology at the University of British Columbia, said some people who obtain recreational marijuana at adult-use dispensaries may also be using it for pain and other health problems.
“We shouldn’t assume that someone who doesn’t have a medical authorization is simply using cannabis for fun,” she said. “Many of these people are treating conditions and improving their quality of life.”
St. Pierre said because pain is a subjective experience and influenced by our psychology, blanket statements about the effects of cannabis for pain are difficult to make.
“Broadly, though, cannabis helps make pain less awful,” she said. “It can also induce some improvements in mood and it can help with sleep.”
Overall, many studies show that cannabis has a moderate effect on chronic pain.
In a 2018 review, a group of Australian researchers combined and analyzed 104 previous studies that looked at the use of cannabis and cannabinoids for chronic non-cancer pain.
Cannabinoids are compounds found in cannabis, of which there are over 100 different ones. The most medically-useful ones are THC, the compound that makes people “high,” and the nonpsychoactive cannabidiol (CBD).
The authors of the review found that 29 percent of people taking a cannabinoid had a 30 percent decrease in their pain. But so did 25.9 percent of people taking an inactive compound, known as a placebo.
It seems unlikely that cannabinoids are “highly effective” for chronic non-cancer pain, the authors write.
Of course, cannabis may not work for everyone. And not everyone can tolerate it.
People also need to weigh the benefits against the risks.
“What we see is that, for some people, cannabis actually increases their sensitivity to acute pain,” said St. Pierre.
Researchers are starting to work out exactly how cannabis relieves chronic pain.
Last year a group from Israel examined the effect of THC on a type of nerve pain that includes sciatica. The study involved 15 men with chronic nerve pain.
They found that THC may relieve pain by disrupting signals flowing between areas of the brain that process emotions and sensory signals.
This fits with what St. Pierre called the “subjective” experience of pain, which includes an emotional component.
“Pain is really influenced by our psychology,” she said. “You can have two people with the same injury, but they have widely different experiences.
CBD may act on the brain in a different way.
When they gave CBD to rats for seven days, the rats had lower levels of pain and anxiety. More research needs to be done to know if CBD works the same way in humans.
In contrast, pain medications like oxycodone, hydrocodone, codeine, and morphine block pain messages sent from the body to the brain by attaching to opioid receptors throughout the body.
While opioids are effective pain relievers, they can also be highly addictive.
With cannabis, some doctors have concerns about people self-treating their pain with cannabis obtained from dispensaries that cater to recreational users.
“They’re dispensing mainly these very high-THC strains of cannabis or of edibles,” said Dr. Daniel Clauw, director of the University of Michigan Chronic Pain and Fatigue Research Center, last year in a forum on the health effects of cannabis.
“Those are not at all the strains that people should be using for most of the medicinal effects of marijuana, especially the analgesic or the pain-relieving effects.”