Sept. 19 (UPI) -- Drugs derived from an active ingredient in marijuana produced only modest increases in pain threshold and tolerance but no reduction in ongoing intensity, according to an analysis of research.
Researchers examined 18 placebo-controlled studies in determining the effectiveness of cannabidiol, which contains less than 0.1 percent of tetrahydrocannabinol, or THC, the psychoactive substance in marijuana that makes users high. The findings were published Wednesday in the Journal of the American Medical Association.
The researchers concluded that cannabis-induced improvements in pain-related situations "may underlie the widely held belief that cannabis relieves pain."
"Our cumulative results indicated that although cannabinoid drugs may prevent the onset of pain by producing small increases in pain thresholds, they didn't significantly reduce the intensity of experimental pain that is already being experienced," Martin De Vita, a doctoral student at Syracuse University who studies interactions between substance use and co-occurring health conditions, told UPI. "Instead, cannabinoid drugs made experimental pain feel less unpleasant and more tolerable."
Medical marijuana has been approved in 31 states and the District of Columbia, according to ProCon.org. Recreational pot is legal in nine states and Washington, D.C.
"Recent research suggests that a growing number of people are using CBD products for medical purposes," De Vita said. "Pain is by far the most common medical reason people cite for using CBD, and they endorse beliefs that it is effective for treating their pain. That being said, more placebo-controlled trials are desperately needed to inform our understandings of cannabinoid analgesia."
The most common clinical use of cannibas use is associated with pain relief.
De Vita led a review of research with data collected from August through November 2017.
"The available research has been primarily focused on cannabinoid drugs that produce psychoactive side-effects, so the potential for adverse effects is an important factor to consider, especially in regards to pain-related functioning," De Vita said. "Although generally speaking, higher doses were associated with larger effects in our study, more research is needed to understand the dose-response more precisely for cannabinoid drugs."
Participants had to be healthy and using an experimentally-controlled cannabinoid preparation in a quantified dose. Participants with chronic pain were excluded.
In the 18 studies, 223 participants were male and 209 were female. The median age was 26.65.
The study analyzed 18 pain threshold comparisons, 22 for intensity, nine for unpleasantness comparisons, 13 for tolerance and nine for mechanical hyperalgesia, which is sensitization caused by exposure to opioids.
The researchers used established pain reactivity outcomes for the categories.
Cannabinoid administration was associated with small increases in pain threshold, small to medium increases in pain tolerance and a small to medium reduction in the unpleasantness of ongoing experimental pain. Cannabinoid administration was not reliably associated with a decrease in experimental pain intensity or mechanical hyperalgesia.
De Vita said combining cannabidiol with other compounds could be more effective in treating pain.
"Research on the effects of Cannabidiol, by itself and combined with other compounds, for example Nabiximols, is ongoing," De Vita said. "Initial trials show promise for certain pain conditions, but our current evidence is still far from conclusive."
"One question that remains," he added, "is whether the observed effects of cannabinoids on pain are being driven by psychoactive effects -- feeling 'high.' Thus, it is important to begin studying the therapeutic potential of non-intoxicating cannabinoids like CBD."
People who use medical marijuana often rely on medical and non-medical prescription drug use, including pain relievers.
In a study published in April, researchers at Stanford University and University College Cork in Ireland analyzed more than 57,000 responses to the 2015 National Survey on Drug Use and Health to determine if medical marijuana users also turn to opioids.
About 1.4 percent of all respondents said they used medical marijuana.
Survey participants using medical marijuana were 60 percent more likely to report prescription drug use, for medical reasons or not, than those who didn't use medical pot.
The U.S. Food and Drug Administration wants to know how people are dealing with pain as it continues to tweak recommendations for opioid painkiller prescription and use.
Other methods to reduce pain acupuncture, chiropractic care, hypnosis and meditation.