Set and Setting: A Research Concept

Roughly 60 years after Timothy Leary and Richard Alpert first wrote about "set and setting" in their 1964 manual on psychedelic sessions, the phrase has migrated from counterculture pamphlets into peer-reviewed neuroscience papers. That migration is interesting. It tells you something about how seriously researchers now take context as a variable, not a footnote, in understanding how a substance produces a particular kind of experience in a particular person.

Before I go any further: in Australia, psilocybin and most classical psychedelics remain Schedule 9 prohibited substances under the Poisons Standard (the document that gives legal force to Australia's drug scheduling system). Possession, use, manufacture or supply outside of a specific legal exemption is a criminal offence under state and territory law. The one narrow exception, introduced by the TGA from 1 July 2023, allows Authorised Prescribers to prescribe psilocybin (rescheduled to Schedule 8 for this purpose) and MDMA within a supervised clinical context. That's it. No other pathway exists for recreational or self-directed use. If someone tells you otherwise, they're either misinformed or trying to sell you something.

With that on the record, let's talk about what "set and setting" actually describes, why researchers treat it seriously, and what its scientific status looks like today.

Where the concept came from

Leary, Alpert and Ralph Metzner used the term in their 1964 work The Psychedelic Experience, but the underlying idea predates them. Mid-century psychiatrist Humphry Osmond, who coined the word "psychedelic" itself in 1957, was already writing about how the conditions surrounding a session shaped its character. Anthropologists studying indigenous ceremonial use of plant medicines had been documenting the same thing, more rigorously, for decades before that.

The ceremonial literature is worth a pause. In those traditions, preparation, community roles, the timing of a gathering and the surroundings were never treated as decoration. They were part of the practice itself. Western researchers arrived at a similar conclusion through a different door, which is why the idea feels less like an invention and more like a rediscovery given a tidy label. For readers who want the wider research backdrop, the history of psilocybin in research sets out how interest in these compounds rose, fell and returned.

"Set" refers to the mindset a person brings: their expectations, emotional state, intentions, prior experiences, and psychological history. "Setting" refers to the physical and social environment: the room, the people present, any music, the relationship between participant and guide. Together they're proposed as primary determinants of how a psychedelic experience unfolds; arguably more influential than dose alone, at least at moderate doses. The notion of a dose–response relationship is useful here, because set and setting is essentially an argument that dose alone gives an incomplete picture of what a person will report.

I'd argue the framework deserves some scepticism. Used loosely, it can seem to justify almost anything after the fact: a good experience proves the setting was right, a bad one proves it was wrong. The version used in trial protocols is more specific than the pop-science one, because it names particular variables in advance, such as preparation, room design and the presence of trained guides. That specificity is what separates a testable research concept from a slogan.

The neuroscience of context sensitivity

Classical psychedelics like psilocybin act primarily as agonists at the 5-HT2A serotonin receptor. This mechanism leads to dramatic increases in cortical excitability and a breakdown of normal default mode network (DMN) activity; the self-referential brain network associated with what we experience as the "narrative self." Studies using fMRI, including a landmark 2012 paper by Carhart-Harris et al. in PNAS, showed that psilocybin produces significant decreases in blood-oxygen-level-dependent signal in DMN hubs like the medial prefrontal cortex and the posterior cingulate cortex.

A quick note on terminology. An agonist is a compound that binds to a receptor and activates it. The blood-oxygen-level-dependent signal is an indirect measure: fMRI does not record neurons firing, it tracks changes in blood oxygenation that correlate with activity. That distinction matters when reading headlines about brain scans, because a change in signal is a proxy, not a direct picture of thought or experience.

What's relevant here is that the 5-HT2A receptor is densely expressed in higher-order cortical areas, the areas most involved in interpretation, expectation and meaning-making. Neuroscientists like Karl Friston have proposed, under the predictive processing framework, that psychedelics effectively increase the brain's reliance on incoming sensory and emotional signals relative to its top-down predictions. In that model, context isn't just background noise; it becomes some of the most salient information the brain is working with.

This is part of why researchers argue set and setting isn't merely a soft behavioural variable. It may interact directly with the neurochemical state the substance induces. The pharmacokinetics are constant across individuals at a given dose; the phenomenology is not, and context is one proposed explanation for that variance. It is only one proposed explanation, and the predictive processing account remains a theoretical model rather than settled fact.

How set and setting is operationalised in clinical research

In the clinical trials that informed the TGA's 2023 scheduling decision, including the Phase 2 trials from MAPS (for MDMA) and work from Johns Hopkins (for psilocybin), set and setting was a structured protocol element, not an optional consideration. Participants underwent preparatory sessions with trained therapists before any substance was administered. The physical room was designed specifically: soft lighting, a comfortable couch, a music playlist selected for the session, eye shades to reduce external visual stimulation, and two trained guides present throughout.

Each of those elements maps back to the concept. Preparatory sessions address "set" by building rapport and setting expectations. The room and the guides address "setting". The broader supervised clinical model treats the whole arrangement as a single package, which is one reason results from trials cannot simply be transplanted into other circumstances.

The question of whether these contextual factors independently influence outcomes is hard to isolate experimentally; you can't easily run a placebo-controlled trial where only the setting varies. Blinding is a persistent problem too, because participants often work out whether they received the active substance, a theme explored in placebo challenges in psychedelic research. If expectation is itself part of the mechanism, then a participant who suspects they received the active compound is carrying a different "set" than one who doesn't.

But researchers have attempted to measure it. A 2022 paper in Psychopharmacology by Haijen et al. examined pre-session psychological variables and found that baseline "surrendering", a measure of openness and acceptance, was significantly associated with the quality of the reported experience. That's a set variable, not a pharmacological one.

Reports in those same studies, and I want to be very clear these are reported accounts within controlled research conditions, not instructions, describe doses in a range that appeared in published trial protocols. Those figures are cited as data points in scientific literature, not as guidance for any kind of self-directed use, which remains illegal. Understanding the difference between preclinical and clinical research helps here: protocol details from a monitored trial describe what was done under oversight, nothing more.

Legal context in Australia: what the 2023 change did and didn't do

The TGA's decision to reschedule psilocybin to Schedule 8 for Authorised Prescribers was specific and narrow. It doesn't legalise psychedelic use. It creates a pathway for psychiatrists who have applied for and received Authorised Prescriber status through the TGA to prescribe psilocybin for treatment-resistant depression. The substance remains Schedule 9; prohibited, for all other purposes. For the mechanics of the change, see the 2023 Australian down-scheduling of psilocybin and the Authorised Prescriber pathway.

The Special Access Scheme also exists as a parallel pathway, allowing access to unapproved therapeutic goods for individual patients on a case-by-case basis, but this is similarly gated through medical professionals and TGA oversight. Neither pathway permits possession or use outside a clinical setting. The Australian Drug Foundation's resources on this are worth reading directly (linked below); they're clearer than most third-party summaries.

A common mistake is to read a scheduling change as a general loosening of the law. Scheduling classifies a substance for the purposes of supply and handling. It does not create a personal right to use it. Because drug offences also sit in state and territory legislation, the full picture involves more than one layer of government, which is covered in state versus federal drug regulation. The reasoning behind the ban on do-it-yourself approaches is set out in why self-medicating with psilocybin is illegal in Australia.

In my view, the media coverage of the 2023 change substantially overstated what it meant in practice. The number of Authorised Prescribers operating as of mid-2024 remained small, access was heavily concentrated in major cities, and the cost of supervised sessions was significant. The regulatory framework exists; the infrastructure hasn't caught up yet.

Set and setting beyond psilocybin

The concept has been extended; sometimes loosely, to other substances. Researchers have proposed analogous context-sensitivity for ketamine, MDMA, and even cannabis. There's an interesting parallel with cannabis research here: the idea that subjective response to tetrahydrocannabinol varies considerably based on prior experience, expectation and environment maps onto the same basic framework. Whether the underlying neuroscience is equivalent is a separate, contested question.

For cannabis specifically, the role of compounds like cannabidiol in modulating the character of the experience has been studied, though again, under strict no-therapeutic-claims framing, describing mechanism is not the same as claiming benefit. CBD's interaction with the endocannabinoid system may modulate THC's effects, but that's a pharmacological question, not a set-and-setting one.

Telling those two kinds of explanation apart is a useful habit. A pharmacological explanation points to what a compound does at a receptor or in a pathway. A contextual explanation points to the person and the surroundings. Real experiences involve both, and research that blurs them can leave readers with the wrong impression of what was actually measured. A related example of an idea stretched beyond its evidence is covered in the entourage effect: history of an idea.

What the research can and cannot tell us

Set and setting is a well-documented research concept with genuine scientific interest behind it. It's also genuinely difficult to study rigorously; the interaction between mindset, environment, neurochemistry and experience is complex, the trials are small, and self-report data has known limitations. The most careful researchers in this space are explicit about those limitations.

Self-report deserves a closer look. Participants describe experiences that are hard to put into words, often after the fact, and their descriptions can be shaped by the questionnaire they are given and by what they expect the study to find. Small samples compound the problem, because a handful of unusual responses can shift an average. When you read a result, it is fair to ask who was enrolled, how they were screened, what the comparison group received and how outcomes were measured. Those questions apply to any trial, but they matter more when the very thing being studied is subjective.

What the research does not do, and what this article does not do, is establish that psychedelic use is safe or beneficial for individuals outside a clinical context. The legal position in Australia is unambiguous: use outside the narrow Authorised Prescriber framework is a criminal offence, and the psychological risks of uncontrolled use, particularly for people with personal or family history of psychosis or certain mood disorders, are documented in the clinical literature. The contraindications discussed in clinical psychedelic research are a good place to see how trials screen participants out, and readers with general questions may find the psilocybin and psychedelics in Australia FAQ useful.

The original Leary-Alpert text is a strange artefact; part ancient Tibetan Buddhist text, part 1960s optimism, part legitimate observation about context. The observation survived. The optimism needed a lot of tempering. The science is still working out what to keep.

Sources

• Scheduling Delegate's Final Decisions, March 2023, Therapeutic Goods Administration (TGA)
• Psychedelics drug facts, Australian Drug Foundation (ADF)
• Carhart-Harris RL et al., "Neural correlates of the psychedelic state as determined by fMRI studies with psilocybin" (2012); PNAS via PubMed/NCBI
• Haijen ECHM et al., "Predicting responses to psychedelics: A prospective study", Psychopharmacology via PubMed/NCBI

Daniel Okoro, Psychedelic science & law writer