A scoping review of mystical-type experiences and mood symptom outcomes in psychedelic therapy clinical trials: comparing life-threatening disease and depressive populations

Background: Psychedelic therapies are gaining attention as tools to alleviate anxiety and depression across various clinical populations. However, the mechanisms behind psychedelics' therapeutic efficacy and the potential differences in how patients with certain diagnoses experience their subjective effects remain unknown. One commonly suggested mediator of positive outcomes across psychedelics trials is the occurrence of mystical-type experiences. Objectives: This scoping review examines the relationship between psychedelic-induced mystical-type experiences and changes in anxiety and depression symptoms, comparing findings across populations with a life-threatening disease (LTD) and other psychiatric populations. Given the unique challenges faced by patients with an LTD diagnosis, this review aimed to determine whether there are any distinct patterns differentiating the effects of mystical-type experiences and mood outcomes in this population from other psychiatric populations. Charting methods: Following a scoping review method, PubMed, Embase, and PsycINFO were reviewed. Eligibility criteria: Clinical trials administering psychedelics to adults and measuring mystical-type experiences and their relationship to anxiety and/or depression outcomes were included. Sources of evidence: = 410 participants) met the inclusion criteria. Five studies administered psychedelic therapy to LTD populations, eight trials administered psychedelic therapy to patients with depression. Results: Across all studies, 69% of trials reported a positive relationship between mystical-type experiences and improvement in anxiety and/or depression outcomes. This relationship was found in 80% of LTD studies and 63% of studies in depressive populations. Conclusion: Mystical-type experiences were commonly associated with reductions in anxiety and/or depression symptoms following psychedelic therapy in both LTD and depressive populations. However, this relationship may depend on multiple factors, including the timing of symptom assessments and therapeutic context. Future studies should examine the variables that affect mystical-type experiences, along with other aspects of set and setting, to determine how to best facilitate positive outcomes induced by psychedelics.