Abstract

For the past decades, scientific research with psychedelic substances has been mainly focused on understanding the therapeutic potential of psychedelic therapies for mental health conditions. This led to a considerable number of studies conducted in clinical controlled settings, and various systematic reviews have been conducted to synthesize findings in particular areas of interest.

At the same time, many studies have explored associations between psychedelic use and mental / physical / behavioral health, which are conducted in naturalistic settings. Contrary to clinical studies, these naturalistic, (typically) observational studies present a larger variability and heterogeneity regarding study design and analyses, outcomes of choice, measures used, and substances. Given the growing amount of naturalistic research and the large diversity of its methodologies, it is of interest to describe and summarize how this research is being conducted. Therefore, the main goal of this study is to conduct a Scoping Review to identify and describe the methodological components of naturalistic classic psychedelic research.

For the purpose of this study, naturalistic observational studies will be considered as those where there was no, or very minimal, interference with the experience by the researchers, and the study was conducted in a setting that was (or very closely replicates) a “real life” setting or opportunity. Typically, these are non-controlled study designs, especially regarding location, substance(s), and dose(s) use.
The review will be performed following the Joanna Briggs guidelines for Scoping Reviews, with the following inclusion criteria for studies: (1) observational in nature; (2) conducted in a “real life” setting or opportunity (clearly not a controlled – laboratorial, hospital, clinical environment); (3) substance used is a classic psychedelic (LSD, mescaline, psilocybin, DMT, ayahuasca); and (4) quantitative measures are reported in the study. A search will be conducted using a combination of search terms related to psychedelic substances and study design in the databases PubMed, PsycInfo, Web of Science, MEDLINE, and the data extracted will be synthesized using narrative techniques.

This review may contribute to a better understanding of current research in naturalistic psychedelic studies, to identify strengths and gaps in the literature, and to describe trends (and possible shortcomings) in the methods currently used.