Placebo Effects of Edible Cannabis: Reported Intoxication Effects at a 30-Minute Delay

Telling people they are consuming a cannabis-infused edible can produce feelings of intoxication even when the product contains no active drug. In a study of 20 participants who were given a placebo lollipop but told it contained a high dose of THC, measures of cannabis intoxication and negative mood showed significant changes over 60 minutes, while positive mood and a general intoxication measure did not. This provides preliminary evidence that the placebo effect extends to edible cannabis products, which have a delayed onset of effect.

Study at a glance

Abstract

Previous research has demonstrated the ability of non-active smoked cannabis cigarettes to induce subjective effects of intoxication (i.e., placebo effect). No studies have been conduced to test whether edible forms of cannabis, which are associated with a significant delay in onset of effect, are able to induce a placebo effect. In the present study, 20 participants were told that they would receive an edible cannabis lollipop containing a high dose of tetrahydrocannabinol (THC), but were instead given a placebo control. Measures of intoxication and mood were taken at baseline, 30 minutes, and 60 minutes post-ingestion of the placebo lollipop. Results of four repeated-measures ANOVAs found significant and quadratic changes across time in cannabis (ARCI m-scale) intoxication (F(2,18) = 4.90, p = .01, η2 = .22) and negative mood (F(2,18) = 3.99, p = .05, η2 = .19). Changes in positive mood and the overall measure of general intoxication (ARCI) failed to reach significance. The present study provides preliminary evidence that a placebo effect can be induced with inert edible agents when participants are told that they are receiving active THC. This is the first known study to demonstrate an edible cannabis intoxication placebo effect.