20 Scientific American, June 2019THE SCIENCE
OF HEALTHClaudia Wallis is an award-winning science journalist whose
work has appeared in the New York Times, Time, Fortune and the
New Republic. She was science editor at Time and managing editor
of Scientific American Mind.Illustration by Celia KrampienIs Pot Any Good
for Pain?
The data are spotty, but there’s still
a reasonable case to be made
By Claudia Wallis“Medical cannabis saved my life,” says Nancy Partyka, a retired
college psychology instructor in Frisco, Colo. For more than 20
years Partyka battled agonizing pain stemming from a car crash
that injured her cervical spine. She tried physical therapy, steroid
injections, acupuncture, exercise and meditation. She endured
five spinal fusion surgeries and plenty of pills. “I was taking Oxy-
Contin, taking Aleve by the handful,” she recalls, but she was spi-
raling downward. “The narcotics suppress your ap pe tite. You
don’t eat right, you are constipated, you feel worse. The dominos
keep falling.” Ultimately Partyka says she found relief in canna-
bis, which is legal in Colorado. Her preferred formula, taken in
an edible form, combines the plant’s two main active chemicals
in a ratio of eight parts cannabidiol (CBD) to one part tetrahydro-
cannabinol (THC). She also uses a topical spray that is equal
parts CBD and THC. “I have a life again,” says Partyka, who is
back to hiking and snowshoeing. “I’m not saying I’m 100 percent
pain-free. But I’m off the opioids. I almost feel normal.”
Anecdotes such as Partyka’s are not hard to find. With opioids
out of favor, and medical marijuana now legal in 33 states , many
people with chronic pain are looking to the nation’s budtenders
for relief. Surveys suggest that pain is the single biggest reason
Americans use medical marijuana, and although cannabis laws
vary, all 33 states permit its use as an analgesic.
The validity of that choice got a big boost in 2017, when the
National Academies of Sciences, Engineering, and Medicine re -
leased a detailed report concluding that there was “substantial
evidence that cannabis is an effective treatment for chronic pain
in adults.” Still, the research leaves a lot to be desired. “The data
are highly conflicting,” says Sean Mackey, chief of the division of
pain medicine at Stanford University Medical Center. He notes
that a number of mostly small randomized clinical trials have
shown “some benefit” for certain types of pain, but larger epide-
miological studies are more equivocal or even negative.
A comprehensive review of the research published last year in
the journal Pain breaks this down. It found that the strongest sup-
port for cannabinoids comes from studies of pain associated with
multiple sclerosis and with nerve damage. “When it comes to the
most common pain problems—back and neck pain, arthritis—very
few studies have been done,” says Gabrielle Campbell, a research
fellow at the University of New South Wales in Australia and a co-
author of the review. “For arthritis, there was only one poor-quali-
ty study.” Research quality was a problem overall, Camp bell points
out: just 15 studies out of 104 that were examined were highly rat-
ed for methodology, and only 21 had 100 or more participants.
Research has been inhibited by marijuana’s status as a tightly
regulated Schedule I drug. Scientists must have a special license to
obtain it. Another challenge is the multiple forms of cannabis: end-
less smokable varieties, plant extracts that can be used topically or
orally, edible gummies, and so on. In addition, the products people
report using are not necessarily what they think they are. CBD oil
may contain more or less CBD than advertised and in clude unla-
beled THC. A 2017 study that examined 84 cannabidiol products
bought on line found that 69 percent misrepresented the content.
Much of the best research on cannabis and pain involves a
pharmaceutical-grade product called nabiximols (Sativex), a plant
extract approved in more than 25 countries for relief of muscle
spasms and related pain due to multiple sclerosis. In the U.S.,
however, the only approved cannabinoids are synthetic drugs for
treating nausea in cancer patients and a new plant-derived drug,
Epidiolex , for rare forms of epilepsy. Nothing explicitly for pain.
It would be easy to conclude, as medical experts and health col-
umnists so often do, that patients should simply wait for better
data and better products. But chronic pain is an urgent problem
for millions of people, many of whom, like Partyka, are not helped
by standard therapies. “When you have a patient in front of you
who has tried 14 different treatments, and you have multiple ran-
domized controlled trials showing an effect for cannabis for that
condition, then I think it’s reasonable to try it if the patient is oth-
erwise appropriate,” says Kevin Hill, director of addiction psychi-
atry at Beth Israel Deaconess Medical Center in Boston.
Hill agrees with European and Canadian guidelines that view
cannabis as a third-tier treatment for pain. As for the holes in the
data, he has an interesting suggestion: In states where cannabis
is legal and taxed, why not direct some of the revenues and a por-
tion of the booming industry profits to finding answers?