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05 · The honest read
What the science does not yet show
If we only showed you the encouraging findings, you would be right to discount them. This page exists so you do not have to take the rest of this site on trust.
Three things are true at once. The findings on meaning and wellbeing are real and have been replicated. The field's methods have known weaknesses that probably inflate the size of reported effects. And almost none of this research was carried out in a retreat setting.
The most serious methodological criticism is that psychedelic trials are extremely difficult to blind. Participants can often tell whether they received the drug, and expectancy alone can produce measurable effects. A 2021 review argued that treatment effects in psychedelic trials are likely to be overestimated for this reason, and noted that trials have generally not reported whether their blinding actually held.1
How this research relates to a Beckley retreat
The studies described here were run as clinical trials, in hospitals or research settings, using standardized synthetic compounds under medical supervision. Beckley is not a clinical program. Our retreats are non-clinical wellbeing experiences that use natural psilocybin and are built around preparation, a guided experience, and integration.
Three uncomfortable facts
Each of these is drawn from the published literature rather than from our own view of it.
Blinding is hard to maintain
A 2021 review argued that effect sizes in psychedelic randomised trials are likely overestimated because of de-blinding and high response expectancy.
Than active controls
In the meditation literature, a review of 47 trials found no evidence that meditation programs outperformed any active treatment tested, namely medication, exercise and other behavioural therapies.
Participants in the core study
The most cited study on psilocybin and lasting personal meaning involved 36 hallucinogen naive volunteers who already participated regularly in religious or spiritual activity.
Where the evidence is genuinely thin
The blinding problem
In a well designed drug trial neither participant nor researcher knows who received the active compound. With a psychedelic this is close to impossible, because the effects are unmistakable. Once participants can tell, expectation becomes part of the result. A 2021 review in Expert Review of Clinical Pharmacology argued that this likely inflates reported effect sizes across the field, while noting that trials have generally not measured whether blinding succeeded.1
Small and self selected samples
The foundational study on psilocybin and personal meaning involved 36 volunteers who had never used a psychedelic and who already took part in religious or spiritual activity regularly.2 People who volunteer for a psychedelic study are not a random sample of the population, and results from such groups may not transfer.
Trials are not retreats
Nearly all of the strongest data comes from controlled settings with screened participants, fixed doses and clinical supervision. A retreat differs in context, group dynamics, duration and support. We are not aware of a randomised trial testing whether a retreat reproduces the outcomes reported in clinical research.3
Long term data is limited
Follow up in most studies is measured in weeks or months. The fourteen month follow up in the Hopkins work is unusually long for this field.2 What happens across many years, and for whom, remains largely unstudied.
Our own data is not evidence
We collect guest surveys and we find them useful. They are self reported, collected by us, and have not been through peer review. They tell you how our guests describe their experience. They do not constitute clinical evidence and we do not present them as such.3
What we do still stand behind
Stating the limitations is not the same as saying nothing is known.
- The meaning findings are real and replicated. Participants rating a session among the most meaningful experiences of their lives, more than a year later, has held up across follow ups and was corroborated by people who knew them.2
- The neuroimaging is solid as description. The observed changes in brain network activity are well documented, even though their link to lasting benefit is not established.4
- The safety framework is well established. Screening criteria and session support protocols come from published guidance and are widely adopted in research.5
- Nature connectedness and meditation have their own support. Modest but real, and independent of anything to do with psychedelics.6
Why this page exists
A research page that only carries good news is a marketing page. Our audience includes clinicians, journalists and academics who will check. We would rather be the provider that told you the limitations first.
References
Every figure and finding stated on this page traces to one of the sources below.
- Muthukumaraswamy, S., Forsyth, A., Lumley, T. Blinding and expectancy confounds in psychedelic randomized controlled trials. Expert Review of Clinical Pharmacology, 2021. View on PubMed
- Griffiths, R.R., et al. Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance. Psychopharmacology, 2006. View on PubMed
- Beckley Retreats editorial assessment. Statements about the absence of published evidence, and about the status of our own survey data.
- Carhart-Harris, R.L., et al. Neural correlates of the psychedelic state as determined by fMRI studies with psilocybin. PNAS, 2012. Read the full text
- Johnson, M.W., Richards, W.A., Griffiths, R.R. Human hallucinogen research: guidelines for safety. Journal of Psychopharmacology, 2008. View on PubMed
- Capaldi, C.A., et al. The relationship between nature connectedness and happiness: a meta-analysis. Frontiers in Psychology, 2014. Read the full text. Goyal, M., et al. JAMA Internal Medicine, 2014. Read the full text