Is cannabis a good choice for treating chronic pain?
That’s a question shared by doctors, researchers, and people living
with chronic pain. But it’s a surprisingly difficult one to answer.
A recent
review of cannabis products in the journal
Annals of Internal Medicine looked at the existing body of knowledge related to this question.
And the answer? We just don’t have enough information to know for sure.
So how did we get here?
Cannabis and the compounds related to it — collectively referred
to as cannabinoids — can include chemicals such as tetrahydrocannabinol
(THC) and cannabidiol (CBD).
These compounds have found their way into a variety of products from chocolates
and candies to body balms and massage oils over the last decade. During
that time, Washington DC and 19 states
legalized recreational cannabis use, while an additional 37 states legalized medical uses for
cannabinoids.
The state-level legalization and expansion of the cannabinoid market are
complicated by the fact that at a federal level, cannabis is still classified
as an illegal Schedule I substance under the Controlled Substances Act.
According to the US Drug Enforcement Administration (DEA), the
schedule system accounts for a substance’s potential for abuse and habit formation,
safety, and medical uses. Schedule I substances are considered to have
the highest potential for abuse and no acceptable medical uses.
In the case of cannabis, this classification was made more than half a
century ago. And it’s just one of several challenges for researchers.
Dr. Vernon Williams, a board certified neurologist, pain management specialist, and director
of the Center for Sports Neurology and Pain Medicine at Cedars-Sinai Kerlan-Jobe
Institute in Los Angeles told Healthline that chronic pain is complicated to study.
“It’s not just about an electrical signal,” Williams
said. “There are emotional and environmental conditions that affect
pain, as well as expectation and other contributing factors.”
“There’s a very strong placebo response in pain studies that
can be difficult to overcome in clinical trials. Then there are the realities
that chronic pain can be caused by so many different and varying etiologies,
that pain is subjective, and that it is so complex,” he said.
“But the other social, legal and political aspects of cannabinoids
further complicate the ability to easily study their effects on chronic
pain,” Williams added.
Daniele Piomelli, Ph.D., director of the Center for the Study of Cannabis at the University
of California, Irvine, told Healthline he agreed there are many obstacles
to cannabis research.
“In addition to regulatory hurdles, which for cannabis are greater
than most other drugs, [the] cost is a problem. Funding a large clinical
study without a corporate sponsor (e.g., a pharmaceutical company) is
virtually impossible,” Piomelli said.
If cannabinoid research is so difficult, why should we even pursue it?
One reason could be to cut down on the use of opioids.
“The main current treatment for chronic pain [is] the opioids, which
don’t work well in chronic pain, are highly addictive and are rife
with side effects. So, unsurprisingly, many persons living with pain are
hopeful about cannabis,” said Piomelli.
Another reason to study cannabinoids is to make sure that doctors and patients
have a complete understanding of what risks come with their use.
The new review lists potential side effects of cannabis-based products,
including dizziness, sedation, and nausea. Other possible effects that
need further confirmation include psychosis, cannabis use disorder, and
cognitive defects.
“The assumption that cannabinoids are ‘harmless’ is a
view held by many lay individuals, but there are clearly risks associated
with the use of cannabinoids that must be considered, studied, and reported,”
said Williams.
And, most importantly, cannabinoids should be studied to find out if they’re
actually effective at treating chronic pain.
“The National Academy of Sciences committee charged with assessing
the health effects of cannabis and cannabinoids concluded, in 2017, that there is
substantial evidenceTrusted Source for the efficacy of cannabis and cannabinoids in chronic pain in adults,”
Piomelli said
“But substantial evidence is not conclusive evidence, which is what
we need now.”