The calming effects of pain cannabidiol (CBD) may be related to its influence on affective processes, new research shows.
In a pilot study, researchers at Syracuse University, Syracuse, New York, found that patients’ expectations about analgesia appear to be integral to CBD’s purported ability to modulate pain outcomes.
“Our initial findings show that both the pharmacological action of CBD and the psychological expectations of believing that you have received CBD are involved and improve the central nervous system in different ways. [CNS] processes that inhibit pain, “said Martin De Vita, MS, PhD candidate and co-author of the study Medscape Medical News.
“While CBD did not completely eliminate pain or reduce pain intensity, it did make it significantly less unpleasant,” he added.
The study was published online April 22 a Experimental and clinical psychopharmacology.
A key factor in medical cannabis use
Relief of chronic pain has long been a major factor driving the use of medicinal cannabis. Clinical research has focused primarily on Δ9-tetrahydrocannabinol (THC) in combination with CBD or other cannabinoids. Research on the mechanisms underlying the effects of CBD and its role in analgesia other than THC has been scarce.
Even fewer studies have directly investigated the role of cannabinoids or CBD in modulating acute pain.
To assess the effects of CBD and hope on the reactivity of acute pain, the researchers conducted a crossover, balanced placebo study involving healthy adults 18 to 30 years of age. Participants were given inactive coconut oil or CBD and were told they had received inactive coconut oil or CBD. Participants who received CBD were administered 50 mg of pure CBD derived from hemp sublingually in a 0.3 ml solution.
The study enrolled 15 participants, of whom 67% had never used CBD; 86.7% were current users or had never used cannabis. Participants were randomly assigned to one of four experimental sessions: control (indicated to inactive, given inactive), expectation (indicated to active, given inactive), drug (indicated to inactive, given active), and expectation + drug (indicated to active, given active).
Participants were exposed to six experimental heat pain trials that measured pain threshold and tolerance. Analog-scale visual assessments were then performed to measure intensity and unpleasant pain.
Central pain inhibition and perception of pain intensity were assessed with two dynamic pain tests, conditioned pain modulation (CPM) and compensated analgesia (OA).
The results showed that participants experienced significantly greater reductions in pain discomfort in the hopeful condition (paired samples 𝜏 = 3.36; Pg = .006; d = .860), the condition of the drug (𝜏 = 3.17; Pg = .007; d = .820), and the hope + condition of the drug (𝜏 = 2.36; Pg= 0.033; d = .616) compared to the control condition.
A greater degree of pain inhibition (CPM response) was observed in hope (𝜏 = -2.75; Pg = 0.016; d = -.84) and medicine (𝜏 = -3.20; Pg = .006; d = -.84) conditions compared to hope + condition of the drug.
A significant instructional effect on OA (𝐹[1,4] = 7.58; Pg = 0.016; effect size = .351]was also seen. No notable effects on threshold, tolerance, or pain intensity were observed.
“What we found is that CBD and expectations of receiving CBD, both independently and in combination, improve the affective or emotional component of pain,” De Vita said.
“We also saw that CBD and expectation involved CNS processes that inhibit pain, albeit differently, which supports our hypothesis that CBD acts on the CNS from a pharmacological and drug perspective. expectation or placebo analgesia, ”he added.
In addition to sample size, study limitations include the use of experimental measures of pain, single sublingual CBD dosage, age, and lack of drug detection for other cannabinoids.
Do you still have hopes of CBD in the treatment of acute pain?
Commenting for Medscape Medical News, Michelle Sexton, ND, adjunct professor of anesthesiology at the University of California, San Diego, and a researcher with extensive experience in cannabinoid Pharmacology and the use of cannabinoids for pain conditions said, “When we look at the entire literature, I don’t remember anything that points to CBD as a great painkiller.
“It doesn’t compare well with the analgesic effects of THC. They’re not equipotent molecules or have similar mechanisms of action,” he said.
Sexton’s opinion was confirmed in a randomized, double-blind, placebo-controlled trial of the use of 400 mg of oral CBD as a supplement to standard care for adult patients presenting to the emergencies with acute and non-traumatic problems. back pain. These findings, which were published April 21 at Australian Medical Journal, showed no evidence that CBD was beneficial for pain or other outcomes.
Sexton also expressed methodological concerns. “The CPM measure is not a well-accepted production for pain patients and was the only significant effect the study showed,” he said. He noted that the Pg the value was low for this result and 95% confidence intervals were missing.
“You have to be very selective about how your trial is designed and what patient population you select,” he said.
De Vita acknowledged that the findings are preliminary, that more data is needed on individual patient differences and possible confounders that could influence the findings, and that larger sample sizes would increase statistical power.
“For this first human experimental study, we were primarily interested in the effects of drugs and expectations and interactions with space pain,” he said.
“Until now, people were wondering whether or not CBD has a value in pain, and it seems to have a bit of a placebo effect and a bit of a pharmacological effect and it differs, depending on the aspects of the pain you’re looking at. ,” added.
The next step is to study the mechanisms underlying these findings, De Vita said.
De Vita has not revealed any relevant financial relationship. He is currently doing a clinical psychology practice at Brooke Army Medical Center, San Antonio Joint Base, San Antonio, Texas. The views expressed are personal and do not reflect the official policy or position of Brooke Army Medical Center, the U.S. Army Department of Medicine, the U.S. Army Surgeon General’s Office, the U.S. Department of Medicine. Army, Air Force Department, and Department of Defense. Sexton is a consultant for Verséa Pharmaceuticals.
Exp Clin Psychopharmacol. Published online April 22, 2021. Summary