A Systematic Review of Study Design and Placebo Controls in Psychedelic Research
Bibliographic record
Abstract
Introduction: Effective blinding is especially challenging in randomized controlled trials (RCTs) involving psychedelics due to the inherent alterations in consciousness that these compounds induce. In this systematic review and exploratory analysis, we aim at synthesizing the methodologies used in RCTs involving classic psychedelics and identify procedures that can help minimize unblinding and bias. Methods: We completed a literature search that included prospective RCTs published between 1963 and January 2023, in which participants were randomized to receive either a classic psychedelic or placebo. Results: A total of 1402 papers were included in the initial search. After eligibility criteria were applied, 50 papers from 48 clinical trials were included. Most studies were double blinded ( n = 34), used a within-subjects design ( n = 32 studies), and included inert placebos ( n = 35). The majority of studies did not report on the integrity of blinding procedures ( n = 34 studies); however, in studies that did, blinding was unsuccessful. Conclusion: To improve blinding and lower expectancy effects, we suggest incorporating active placebos and utilizing dose response or active comparator study designs.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.030 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.011 | 0.000 |
| Bibliometrics | 0.002 | 0.004 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.000 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".