Pre-to-Post Change in Shame During a Deceptive Psychedelic Placebo Procedure: A Secondary Analysis

Background: Shame is a component that contributes to psychopathology yet few interventions target it directly. Psychedelic-assisted therapy has been investigated as an intervention targeting shame and its associated burden. As part of psychedelic efficacy is mediated by expectation effects the true effect a psychedelic intervention may provide is unknown. Here we examined whether a psychedelic placebo intervention reduces the burden of a shameful autobiographical memory. Methods: Healthy adults (n = 27) received an active-placebo nasal spray containing capsaicin presented as a psychedelic and were randomized to a suggestive or a minimal room setting. Shame was rated on a 0–100 scale before administration and at the end of the session. Pre to post changes in shame as well as predictors of post-session shame (room condition, subjective effects, expectations, acceptance/avoidance, warmth and competence of experimenters) were analyzed via a Bayesian paired t-test and Bayesian linear regression. Results: We found strong evidence for a reduction of shame across room conditions (BF10 = 4.87 × 10^6). More intense positive subjective experience (b = 8.34, 95% CrI [1.06, 15.37], pd = .987) and stronger side-effect expectations (b = 6.26, 95% CrI [0.10, 11.89], pd = .976) was associated with higher post-session shame, i.e., smaller changes in shame. Conclusions: A purely expectation-based intervention was followed by a large reduction in memory- related shame, which was attenuated when the experience was predominantly positive. Suggestion- rich, low-pharmacology procedures containing an exposure-like element may warrant investigation as a lower-risk route to modulating shame in affective disorders.