Researchers in the College of Arts and Sciences at Syracuse University have determined that cannabinoid drugs do not appear to reduce the intensity of experimental pain, but, instead, may make pain feel less unpleasant and more tolerable.
“Patients reliably endorse the belief that cannabis is helpful in alleviating pain; however, its analgesic properties are poorly understood,” says De Vita, graduate researcher in the University's Research Lab on Personality, Addiction and Trauma (REPEAT). “Experimental pain studies of cannabinoid analgesia in healthy adults have produced mixed results.”
Associate Professor Emily Ansell, the study's senior author, said that when ingested, THC binds to receptors in the brain that control pleasure, time perception and pain. This activity boasts the production of dopamine, which Ansell calls the "feel-good chemical," resulting in euphoria or relaxation. Ansell is the director of the REPEAT lab.
The Syracuse University team found that cannabinoid drugs were associated with modest increases in experimental pain threshold and tolerance, no reduction in the intensity of ongoing experimental pain but that it reduced perceived unpleasantness of painful stimuli.
“What this means is that cannabinoid analgesia may be driven by an affective, rather than a sensory component. These findings have implications for understanding the analgesic properties of cannabinoids,” De Vita said in the Syracuse University’s Health and Society publication.
The paper, whose publication coincides with “Pain Awareness Month,” represents the first systematic review of experimental research into the effects of cannabis on pain.
Although the use of cannabis for medical purposes is legal in more than 30 states, the DEA still considers it a Schedule I drug, with no accepted medical use. This classification, De Vita says, poses a significant challenge to researchers interested in studying cannabis' therapeutic effects.
The paper was published in JAMA Psychiatry on Sept. 19, 2018.