Set and setting: where the idea came from and what research shows

“Set and setting” is one of the most quoted phrases in psychedelic culture. It is usually offered as common sense: the same substance can lead to very different experiences depending on who takes it and where. This article asks two narrower questions. Where did the phrase come from? And what has research actually measured about expectancy, environment and mindset as predictors of how an acute experience unfolds?

It describes research. It is not a guide to using anything and does not give instructions, amounts or advice about getting any substance.

What does “set and setting” mean?

In the research literature, “set” usually means the psychological state of the person: expectations, mood and intentions. “Setting” means the physical, social and cultural environment in which an experience happens (Pronovost-Morgan et al., 2023). Hartogsohn describes the phrase as a catch-all for the psychological and environmental factors that shape drug effects (Hartogsohn, 2021).

The idea has a close relative in medicine. In a 2016 paper Hartogsohn compared set and setting with placebo-response theory. Both stress expectancy, preparation and beliefs as non-biological factors in how people respond to a drug. He noted that set and setting applies only to psychoactive drugs and is mainly prescriptive, while placebo theory covers all treatments and is mainly descriptive, and he argued the two can complement each other (Hartogsohn, 2016).

Where did “set and setting” come from?

The sources we could open agree on a rough date and a rough cast of people, and differ in how much weight they put on any one person. Hartogsohn writes that the general principles were first described in the early 1960s by Timothy Leary and colleagues, citing a 1963 journal paper and a 1964 manual, and that the term came into use then as a catch-all phrase (Hartogsohn, 2021).

One correction to a common citation. The 1963 paper is by Leary, Litwin and Metzner, not “Litt”, and the 1964 work is a book, not a paper.

• 1963: Leary, Litwin and Metzner published “Reactions to Psilocybin Administered in a Supportive Environment” in the Journal of Nervous and Mental Disease, volume 137, pages 561–573. The title shows the focus on the environment of a session (bibliographic record). We did not open its full text.
• 1964: Leary, Metzner and Alpert published The Psychedelic Experience: A Manual Based on the Tibetan Book of the Dead (University Books). It is cited as a source of the core definitions of set and setting (Pronovost-Morgan et al., 2023; Hartogsohn, 2021). We did not read the book itself.
• 1967: Metzner and Leary, in “On Programming Psychedelic Experiences” (Psychedelic Review 9), asserted that set and setting could be used to “program” the experience, according to Hartogsohn (Hartogsohn, 2021).

Was the idea new in the 1960s?

Not entirely. Hartogsohn’s 2017 history traces the concept from 19th-century Parisian hashish-using groups through 1950s research on non-drug factors in psychopharmacology and the extra-drug techniques of psychedelic therapists, up to Leary’s formulation (Hartogsohn, 2017). In a separate paper he lists examples of earlier attention to context: anthropologists and a few psychiatrists discussing contextual factors only sporadically (he cites an 1896 account of the mescal plant and ceremony), mid-century writers noting the roles of personality, the clinician and the physical and social setting, and Eisner and Cohen (1958) on expectations and intention in LSD psychotherapy (Hartogsohn, 2021). We have taken those examples from Hartogsohn’s citations and have not read the earlier works.

The same paper says shamanic traditions have long used songs, smoke and sacred objects as contextual methods (Hartogsohn, 2021). In other words, the vocabulary is recent, while the practice of shaping an experience with ritual is much older. For one well-known account of a ritual context, see our article on María Sabina and the Mazatec veladas.

What did Zinberg add in 1984?

Norman Zinberg’s Drug, Set, and Setting: The Basis for Controlled Intoxicant Use (Yale University Press, 1984) is the other work usually cited with the phrase. The sources we could open cite it alongside Hartogsohn’s history for the phrase being commonly referred to as set and setting (Hartogsohn, 2021). The subtitle points to Zinberg’s interest in how contexts shape controlled use of intoxicants, which is a different emphasis from the laboratory and therapy settings of the 1960s. We could not open the book or a publisher’s description, so we do not summarize its argument here.

Do studies show that mindset and environment matter?

Several designs have been used, each with a different strength. Pooled laboratory data can compare drug and non-drug predictors. Prospective surveys can follow people through real-world experiences. Placebo experiments can ask what context does without any drug. None of them settles the question alone.

Laboratory sessions: Studerus et al., 2012

Studerus and colleagues pooled data from 23 controlled psilocybin studies: 409 administrations to 261 healthy volunteers. They tested 24 possible predictors, from age, personality and mood to setting and dose, against 15 measures of the acute response (Studerus et al., 2012).

• Dose was the strongest predictor of every outcome, and its effect on overall consciousness alteration was more than twice that of any other predictor.
• Several non-drug factors also mattered. A personality trait called absorption was the second most important predictor and was linked to mystical-type experiences and visual effects. Greater emotional excitability before dosing was linked to both more spiritual experience and more anxiety. Higher psychological distress was linked to weaker mystical-type experiences.
• The only “setting” variable available was whether a session took place in a PET scanner. Those sessions were associated with markedly more anxiety.

The authors list limits. Only dose was assigned by the researchers, so the other associations are observational. Most of the variance in outcomes was unexplained. Expectancy could not be measured or controlled well, the studies had not been designed to test predictors, and the volunteers were young, educated and high-functioning (Studerus et al., 2012). That is a thin test of “setting”, since there was almost no variation in it.

A prospective survey: Haijen et al., 2018

Haijen and colleagues, a team including Carhart-Harris, ran an online prospective study of people who had already planned to take a classic psychedelic on their own initiative. Participants completed five surveys from one week before to four weeks after, and the number of respondents fell from 654 at the start to 212 at the end (Haijen et al., 2018).

• Mystical-type experiences predicted larger gains in a well-being measure at two and four weeks, whereas challenging experiences and visual effects did not.
• Clear intentions were associated with more mystical-type experiences. A prepared, positive mindset and recreational intentions were associated with fewer challenging experiences.
• Dose and the trait absorption predicted the intensity of all acute measures, and baseline traits explained the most variance in well-being change.
• Comfort with the setting and the people present was reported to predict higher well-being at two weeks.

The limits are large and are stated by the authors: no control group or placebo, a self-selected sample with positive attitudes towards psychedelics, self-reported substances and doses, and heavy attrition (Haijen et al., 2018). Self-built items measured set and setting, and some had not been validated. The authors describe the work as an early step towards evidence-based guidelines, not as proof of cause.

A placebo experiment: Olson et al., 2020

Olson and colleagues tested what context alone can do. In a single-arm study, 33 students spent about four hours in a group setting with music, paintings and coloured lights. They were given a placebo described as resembling psilocybin, and confederates acted out its supposed effects. Responses varied widely: many people reported no change, some reported effects comparable to moderate or high doses of psilocybin on a rating scale, and about 61% verbally reported some effect (Olson et al., 2020; abstract read via Europe PMC). The authors concluded that context and expectations can produce psychedelic-like effects without the drug.

This is a proof of concept, not a measure of how large expectancy is in typical sessions. It was a small, single-arm study with a heavy manipulation. A 2023 review of placebo in psychedelic research also cites a study in which ayahuasca ceremony participants given placebos reported psychedelic effects, and describes expectancy as specific beliefs about the likelihood of future events (Pronovost-Morgan et al., 2023).

The case for studying context: Carhart-Harris et al., 2018

A 2018 paper in the Journal of Psychopharmacology by Carhart-Harris, Roseman, Haijen and colleagues argues that the way classic psychedelics act on the serotonin 2A receptor and neural plasticity should make their effects highly sensitive to context. The authors propose a study design to test this and report new findings on contextual factors that shape the quality of experience and on how acute experiences relate to long-term mental health (Carhart-Harris et al., 2018; abstract read via Europe PMC). The paper is partly an opinion and framing piece. We read only the abstract, so we do not repeat its numbers.

What do these studies have in common, and where do they fall short?

Three problems recur. First, the same people choose their mindset and setting and choose to take part, so an association between “feeling prepared” and a good experience may reflect who the person already was. Second, the concept is wide, which makes it hard to test: almost any difference could be assigned to set or setting after the fact. Third, expectancy, the broader measure behind many of these claims, is difficult to separate from the drug effect, because a strongly altering substance is hard to hide from the person taking it.

Do researchers even agree what set and setting is?

Not fully. In 2025, Pronovost-Morgan and colleagues ran a four-round Delphi study of 89 experts from 17 countries to agree what to report about setting in psychedelic clinical trials. They reached consensus on 30 items in four groups: physical environment, dosing-session procedure, therapeutic framework and protocol, and subjective experiences such as trust and safety (Pronovost-Morgan et al., 2025).

The same experts were far less aligned on the concept itself. Roughly equal shares agreed (37%) and disagreed (42%) that set and setting can be studied separately, and their average estimate of how much the two overlap was 49% (Pronovost-Morgan et al., 2025). The authors note that many trials omit basic details such as location and physical environment, that expert opinion is not empirical evidence, and that the guidelines still need testing against outcomes.

What we still don’t know

• How much of the variation in acute experiences is explained by context, once dose and a person’s traits are accounted for. In the pooled laboratory data, most of the variance was unexplained.
• Whether the associations in surveys of self-selected people hold in controlled designs where set or setting is varied on purpose.
• How to measure expectancy without changing it. Asking someone what they expect may itself shape what they report.
• Whether set and setting are separable at all, given experts’ split opinion on the question.
• How findings from healthy volunteers and laboratory or survey samples apply to anyone else. They do not establish what is safe or advisable for an individual.

The careful version of the story is that the idea has a documented history, that it is plausible and partly supported, and that most of the best-known evidence is associational. For the wider science, see our guides to what psilocybin is and how psilocybin compares with LSD and DMT.

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