The Expectancy Effect and Psychedelic Microdosing: An investigation of whether expectation manipulations can enhance analgesic and cognitive performance

Abstract

The utilisation of psychedelics in healthcare is gaining popularity as a therapeutic tool for various physical and psychological disorders. Albeit less studied, psychedelic microdosing is gaining more attention from researchers. Current anecdotal reports and observational studies proclaim various benefits from psychedelic microdosing. However, scientifically rigorous randomised controlled trials are limited. It is, therefore, unclear whether the reported benefits result from psychedelic microdosing or psychosocial factors, namely placebo effects. The present study investigated whether manipulated expectations of the analgesic or cognitive benefits of microdosing can influence individuals' objective performances and subjective perceptions of performance on a series of cognitive and analgesic tasks. Participants were randomised into three expectation groups; The analgesia manipulation group were informed that microdosing has analgesic effects, The cognition manipulation group were informed that psychedelic microdosing has cognitive benefits, and the control group did not receive any expectations. All participants consumed a placebo pill containing 100mg of Niacin, which they were told was a psychedelic microdose. Objective performance scores and subjective ratings of felt pain and cognitive function were recorded at baseline and post-microdose consumption. Participants' perceptions of felt pain relief and cognition enhancement were also collected post microdose consumption. Eighty-eight participants completed the experimental session; seven were excluded from the initial analysis. 84% of participants believed they consumed a psychedelic microdose. The 13 participants (16%) who believed they consumed a psychedelic microdose were also excluded from the analysis. The results indicated that the analgesia manipulation group held higher pain reduction expectations than the other two groups. In comparison, participants in the cognition manipulation group held higher expectations of memory enhancement but not concentration or problem solving. Regarding pain outcomes, the analgesia manipulation group reported greater analgesia compared to the cognition manipulation group. Regarding cognition, neither objective performance nor reports of cognitive enhancements were shown in the cognitive manipulation group. The present study is the first to investigate the relationship between placebo effects and psychedelic microdosing. Further, it demonstrates a novel experimental design that can effectively investigate microdosing. The findings suggest that people's expectations can influence the reporting of microdosing benefits– particularly regarding analgesic effects. The extent to which expectation contributes to broader reports about microdosing effects is still unknown and thus requires further investigation. Future research should continue to explore whether expectancies contribute to other reported microdosing effects and whether specific populations are more at risk of placebo responding.