The Effects of Cannabidiol and Analgesic Expectancies on Experimental Pain Reactivity in Healthy Adults: A Balanced Placebo Design Trial
Date of Award
Doctor of Philosophy (PhD)
Maisto, Stephen A.
Cannabidiol, Cannabinoids, CBD, Expectancies, Pain, Placebo Analgesia
Clinical Psychology | Psychology | Social and Behavioral Sciences
Experimental pain trials have been unable to determine whether cannabinoid analgesia is attributable to intoxication, analgesic expectancies, and/or pharmacological action. One approach to resolving this issue involves testing the effects of analgesic expectancies and cannabidiol (CBD), a non-psychoactive cannabinoid, on human pain reactivity using a balanced placebo design. Despite its frequent use for pain relief, no experimental research has tested the analgesic effects of CBD in humans. Using a within-subjects 2 x 2 balanced placebo factorial design, we experimentally tested the effects of CBD and expectancies for receiving CBD on pain reactivity (i.e., pain threshold, tolerance, intensity, unpleasantness, conditioned pain modulation, offset analgesia) by manipulating both drug administration (given inactive substance or given CBD) and instructions (told inactive substance or told CBD) among 15 healthy humans. Participants completed 4 separate experimental sessions over the course of 4 weeks and were assigned to a different manipulation condition at each session: told inactive – given inactive (control); told active – given active (expectancy+drug); told inactive – given active (drug); and told active – given inactive (expectancy). We did not find significant effects for pain threshold, tolerance, or intensity. We found significant reductions in pain unpleasantness for the expectancy, drug, and expectancy+drug conditions when compared to the control condition. We also observed significant increases in CPM (e.g., greater pain inhibition) in the expectancy and drug conditions. Lastly, we found a significant main effect of instructions on OA, such that the OA response was significantly larger (e.g., greater pain inhibition) when participants were told that they received CBD, regardless of drug content. Overall, our results indicated that separate pain outcomes can be differentially affected by CBD and/or expectancies for receiving CBD. These findings suggest that the analgesic profile for CBD is complex and multifaceted.
De Vita, Martin, "The Effects of Cannabidiol and Analgesic Expectancies on Experimental Pain Reactivity in Healthy Adults: A Balanced Placebo Design Trial" (2021). Dissertations - ALL. 1451.