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"I think there is definitely a lot of excitement around [medical marijuana]," said Kevin Boehnke, Ph.D., research investigator at the Department of Anesthesiology and the Chronic Pain and Fatigue Research Center at the University of Michigan. "It's always nice to have an extra tool in the toolbox, especially one that has been used for thousands of years and that people know to be relatively safe."
But two things are safe and effective. When it comes to treating pain, does CBD actually work, and how good?
What constitutes & # 39; pain & # 39 ;?
Before digging into the research, it is helpful to understand how experts classify "pain."
"In the group [research] that I am part of, we think of pain that comes in three different flavors," says Boehnke. "One of them is neuropathic pain, and it is caused by injury or inflammation of the nerves." Think: carpal tunnel syndrome or sciatica.
"Then it's acute, or nociceptive, pain," Boehnke says. Acute pain usually occurs as a result of a personal injury or tissue injury, such as a broken bone or arthritis caused by bone scrubs.
"Finally, there is centralized pain, which has recently been called nociplastic," says Boehnke. "And there is something more like fibromyalgia or some of the other chronic overlapping pain conditions – migraine, tension headaches – that have been more difficult to characterize scientifically and clinically because there is no specific pathology that you can identify on an X-ray or fMRI."
Because the different types of pain do not always respond to medicines in the same way, it may be difficult to make sweeping generalizations about the effect of CBD on pain. But, with that said, here's what scientists know so far.
Early research is … not super helpful
Want to look at high quality studies that specifically test CBD's effect on pain? It is not. Until December 2018, the federal government's CBD was classified as a Schedule I drug (along with marijuana), making it extremely difficult to study. Now that CBD is legal under the circumstances, that may change.
"There are many studies done on animals, and they tend to show that it is anti-inflammatory and that it has some analgesic effect," says Boehnke. "Unfortunately, they have not been well translated into humans."
But that is not to say that studies focusing on medical marijuana and pain do not exist. They do. They usually only look at the use of CBD in conjunction with THC, or delta-9-tetrahydrocannabinol, the compound in cannabis that can make you "high." That's because scientists believe the two work better together.
"If you take them together, you can tolerate more THC without having the same type of side effects," Boehnke says, referring to THC's penchant for causing intoxication and impairment. "Taking CBD and THC together, compared to a similar amount of THC alone or CBD alone, seems to have better analgesic effects."
Indeed, a number of meta-analyzes have been published that evaluated the strength of data on cannabis and pain. The problem is that they have come to somewhat contradictory conclusions.
A 2017 review by the Department of Veterans Affairs found "low strength evidence that cannabis preparations with precisely defined THC cannabidiol content (most in a 1: 1 to 2: 1 ratio) can alleviate neuropathic pain, but insufficient evidence in populations with other types of pain. "
But a report from the National Academies of Sciences, Engineering and Medicine (NASEM) published the same year concluded that was " decisive or substantial evidence "that cannabis is effective in treat chronic pain also as nausea and vomiting after chemotherapy and multiple sclerosis-related muscle spasms and stiffness.
And another third review, this time from Cochrane, one of the most respected research organizations, found that "there is no good evidence that any cannabis-derived product works for chronic neuropathic pain."
Why Experts Are Still Hopeful
Available research may seem like a mute, but it does come with many caveats that can actually work in favor of cannabis.
"In all these systematic reviews they mention the limitations of existing studies," Boehnke says. "They're usually small studies. They don't give cannabis or cannabinoids to people for a long time. They don't do a good job of figuring out exactly the underlying pain phenotype. And, perhaps most importantly, don't use cannabis products that are representative of what people use. today. "
One reason why the U.S. Drug Enforcement Administration (DEA) stronghold is the legal production of marijuana for research. The University of Mississippi, which is funded by the National Institute On Drug Abuse, is currently the only DEA-authorized marijuana provider. In 2016, the DEA said they would accept applications for additional suppliers, but that effort appears to have stalled within the Trump administration.
Unfortunately, researchers have reported that university-grown cannabis is of low quality, contains mold and is genetically less like marijuana and more like hemp, a type of cannabis characterized by its extremely low levels of THC.
Another reason is that a large portion of the studies use synthetic, single-molecule cannabinoids instead of the medical marijuana you will find on a dispenser, which may contain more than 400 different chemical compounds.
"If someone uses a flower or edible or often even a concentrate [from a dispensary] they will get many, many different compounds in there that can potentially be active together in different ways to provide different types of pain relief," says Boehnke.
How cannabis can be beneficial
As NASEM noted in its 2017 review, "very little is known about the efficacy, dose, route of administration or side effects of commonly used and commercially available cannabis products in the United States." And that's exactly why pain researchers as Boehnke cares about testing the entire cannabis plant – all those hundreds of compounds can help explain if and how cannabis relieves pain.
"Although rooted in simplicity, it may be presumptuous to assume that the main clinical effects of cannabis are only derived from THC and cannabidiol (CBD)," wrote Canadian researcher Amol Deshpande, MD, and Angela Mailis, MD in The Journal of Applied Laboratory Medicine . What goes astray in rhetoric is the importance of associated compounds found throughout the plant … Although the biological activity of many of these still needs to be explored, preparation suggests that some may act synergistically to produce an entourage effect. . "
With more research, experts could also discover that CBD alone can actually relieve pain. Early this year, an animal study in pain investigated how CBD can interact with serotonin receptors, which are believed to play a role in pain, depression and anxiety.  "It's a hypothesis," Boehnke says. "There are many ways CBD can encourage these effects. It's only tough to know because CBD is such a promiscuous molecule. "
What the future holds
DEA's planning for CBD and the FDA's approval of Epidiolex, a CBD-based medication used to treat rare forms of childhood epilepsy, are likely to have a major impact on the research space. "That means that clinical trials of CBD can potentially be made much easier," Boehnke says. And there may be several prescription drugs on the horizon.
Sativex, a cannabis-based pharmaceutical product containing 1: 1 THC and CBD, has already been approved in several countries to treat neuropathic pain, multiple sclerosis-related muscle spasms and stiffness, and severe pain from advanced cancer and is currently under evaluation. in clinical studies in the United States.
Another bright spot? Cannabis potential effect on the opioid epidemic: A growing body of research shows that the combination of cannabinoids and opioids is stronger than opioids alone, which can lead to reduced opiate doses. And a 2019 study found that 80% of chronic pain sufferers say they've replaced cannabis for traditional painkillers (both opioids and benzodiazepines) after experiencing fewer side effects and better symptom management.
Although CBD and cannabis research are promising, experts acknowledge the current limitations. In May of this year, the American Academy of Pain Medicine published a statement urging federal agencies to reschedule medical cannabis to encourage research that leads to responsible regulation. Whether new legislation will follow remains to be seen.
"It's frustrating," Boehnke says. "Because we're in this room where people use these things all the time, but science is pretty far behind politics."
The information in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified healthcare professional about any questions you may have about a medical condition or health goals.