Glossary

A working vocabulary for the journey and what comes after.

Plain-language definitions of the terms that come up most often around psilocybin journeys and integration — ego dissolution, set & setting, the default mode network, the REBUS model, shadow work, and more. General scientific and cultural definitions; the specific working method behind each is in Maya Allan's Psilocybin Integration Guide.

The experience itself

Ego dissolution (Ego loss, Self-dissolution)#: The temporary softening or disappearance of the felt sense of being a separate self during a psilocybin experience. Brain-imaging studies associate it with disrupted default-mode-network connectivity and broader changes across networks. Subjective reports range from boundary blurring to a total felt unity with surroundings. It is usually reported around the peak of the experience; no study has timed it as a separate phase. For most people it is temporary and, by itself, not known to cause physical harm; lasting difficulty is reported in a minority and is a reason to seek help.
Ego death (Complete ego dissolution)#: The most intense form of ego dissolution: a temporary, complete loss of the sense of personal identity, often described as feeling like dying. It differs from milder ego dissolution in completeness rather than kind. In the research literature it is reported mainly toward the higher end of the dose range and around the peak of the experience; this is descriptive, not dosing guidance. The 'death' is metaphorical — the ordinary sense of self returns as the effects fade, usually within hours. Some people later describe it as the most significant part of their experience; others find it frightening, and lasting distress afterward is a reason to seek help.
Mystical experience (Unitive experience, Cosmic consciousness)#: A category of experience — reported in psychedelic sessions, in meditation, and spontaneously — characterized in the research literature by unity, transcendence of time and space, ineffability, a noetic sense of insight, sacredness, and positive mood. Measured with questionnaires such as the 30-item Mystical Experience Questionnaire (MEQ30; Barrett, Johnson and Griffiths, 2015), building on Griffiths et al. (2006). In several psilocybin trials, higher mystical-experience scores have been associated with larger reported benefits; whether the experience causes the benefit or accompanies it is debated among researchers.
Difficult experience (Challenging experience, Bad trip (outdated))#: A psychedelic experience involving intense fear, anxiety, paranoia, confusion, or distressing imagery. Current research literature prefers 'difficult' or 'challenging' to the older 'bad trip'. In a large survey of people describing their most difficult psilocybin experience (Carbonaro et al., 2016), many rated it among the most difficult events of their lives and, in retrospect, also among the most meaningful, while some reported lasting problems and a few sought treatment. A separate study of people who experienced extended difficulties (Evans et al., 2023) documents that such difficulties can last weeks to years. Because both studies recruited people who had already had difficult experiences, neither shows how often lasting harm occurs; screened clinical trials report serious lasting harm as uncommon, and rates outside such settings are not well established. Persistent distress after an experience is a reason to seek professional help.
Re-entry (Coming down)#: The phase of a psychedelic experience as effects subside. In controlled dosing studies the effects of oral psilocybin have largely faded by around six hours, so re-entry is the later part of that window. Often described as the most emotionally tender phase, when the sense of self is reconstituting. Gentle physical movement, writing soon after, and avoiding screens or news are practical suggestions for this phase, not findings.
Afterglow #: A period of heightened well-being, emotional openness, and clarity that some people report after a meaningful psychedelic experience. The research literature describes these subacute effects as lasting from days to a few weeks (Majić et al., 2015; Evens et al., 2023). Animal studies show changes in neural plasticity in the days after psychedelics, and some researchers propose that this may make the period after an experience relevant to integration; that link is a hypothesis, not an established finding in humans, and there is no evidence that changes begun in this window last more reliably than others.
Ineffability #: One of the dimensions of mystical experience described in the research literature: the felt sense that the experience cannot adequately be put into words. Many people report it after intense psychedelic experiences, often alongside frustration at the limits of language. Some turn to art, movement, breath, or sound to express what words cannot; that is a common practice, not a research finding.
Noetic quality #: Another dimension of mystical experience: the sense that genuine knowledge was gained — that the experience revealed something true beyond ordinary thought. Often described as 'knowing' rather than 'thinking' and marked by unusual certainty; William James named it in 1902 as a hallmark of mystical states. That certainty is a feature of the experience, not evidence that its content is true, which is one reason reflection afterward matters.

Frameworks & models

Integration (Post-journey integration, Psychedelic integration)#: The process of working with the insights, emotions, and material that surfaced during a psychedelic experience so that they inform everyday life over time. Common practices include journaling, conversation with trusted people or a therapist, somatic or contemplative practices, and deliberate changes in behavior. Researchers and practitioners widely emphasize integration, but which practices help, for whom, and how much has not been established by controlled research — the evidence is mostly clinical experience and self-report. Distinct from interpretation: integration is what you do afterward, not only what the experience meant.
Set (Mindset)#: Half of the 'set and setting' framework: a person's internal state going into a psychedelic experience — mood, expectations, intentions, current mental-health stability, and recent life context. The framing was popularized in the 1960s by Timothy Leary and colleagues and remains standard vocabulary in research. Studies of what predicts psilocybin responses find that mindset and expectation are among the non-drug factors associated with how an experience unfolds (for example Studerus et al., 2012; Haijen et al., 2018), alongside dose and setting. Included here as vocabulary, not as preparation guidance.
Setting (Environment)#: The other half of 'set and setting': the external context of a psychedelic experience — physical space, the people present, sound, light, perceived safety, and time available. Clinical trials control setting deliberately (a calm room, trained monitors present) and treat it as a safety factor, and studies of naturalistic use also associate setting with how experiences unfold. Described here as vocabulary. This site does not provide preparation or use guidance.
Default mode network (DMN)#: A network of brain regions — including the medial prefrontal cortex, posterior cingulate cortex, and angular gyri — that is most active during self-referential thought, autobiographical memory, and mind-wandering. Carhart-Harris and colleagues (2012) reported reduced activity and connectivity in DMN hubs under psilocybin, and later work has linked such changes with reports of ego dissolution; a 2024 precision-imaging study found psilocybin desynchronizes activity across the brain, most strongly in the DMN. How central the DMN is to psychedelic effects remains an open research question, and the nickname 'the brain's self-system' is a simplification.
Shadow (Jungian) (Shadow material, Shadow self)#: From Carl Jung's analytical psychology: the rejected, denied, or unconscious aspects of the psyche — impulses, traits, and memories the conscious self has disavowed. People sometimes report that psychedelic experiences bring such material into awareness, as imagery or as emotion. In Jungian and related traditions, working with the shadow means acknowledging and reintegrating these aspects rather than re-suppressing them; similar ideas appear in transpersonal psychology and Internal Family Systems. A psychological framework, not a clinical finding.
Inner child (Younger self)#: A construct in several psychotherapy traditions for the childhood self that persists within the adult — the patterns, needs, wounds, and joys formed early in life. Inner-child work appears in Internal Family Systems, gestalt therapy, and some somatic approaches. Some people report that psychedelic experiences bring memories or feelings from childhood into vivid awareness; reflection afterward may involve relating to those younger parts with care rather than overriding them. A framework for reflection, not a treatment claim; with a significant trauma history, this is work for a trauma-trained professional.
REBUS model (Relaxed Beliefs Under Psychedelics)#: A theoretical framework proposed by Robin Carhart-Harris and Karl Friston (2019): psychedelics are thought to relax the brain's high-level prior beliefs, letting more bottom-up sensory and emotional signal through, which the model uses to explain both the possibility of insight and, in unstable conditions, destabilization. It is a model that generates research hypotheses, not an established mechanism, and it does not by itself show that integration practices change outcomes.
Entheogen #: From the Greek for 'generating the divine within' — a term coined in 1979 (Ruck, Bigwood, Staples, Ott, Wasson) for plants, fungi, and synthetic compounds used in religious or spiritual contexts. Includes psilocybin mushrooms, peyote, ayahuasca, LSD, DMT, iboga, and others. Used to distinguish ceremonial or spiritual use from recreational use without implying judgment on either.

Practice & support

Trip sitter (Sitter, Sober sitter)#: A cultural term for a sober person who stays with someone during a psychedelic experience to help keep them safe. Distinguished from a guide (who actively shapes the experience) and a therapist (who provides clinical care). Clinical research uses the parallel role of trained session monitors, and regulated programs require licensed facilitators. Defined here as vocabulary; this site does not provide guidance on conducting or supervising psychedelic use.
Psychedelic-assisted therapy (PAT, Psychedelic-assisted psychotherapy)#: A treatment model studied in clinical trials in which a psychedelic (for example psilocybin, or MDMA) is given in a controlled setting as part of structured psychological support. Trial protocols typically include preparation sessions, a supervised dosing session with trained monitors, and follow-up integration sessions. As of September 2026, no classic psychedelic or MDMA product is approved by the US FDA: psilocybin for treatment-resistant depression is the furthest along, and MDMA for PTSD was declined by the FDA in 2024; a resubmission was reported in August 2026. Esketamine, a ketamine-derived nasal spray, is FDA-approved for depression but is not a classic psychedelic. Defined here as vocabulary, not as a treatment recommendation.
Harm reduction #: A public-health approach that aims to reduce the harms of drug use without requiring abstinence, endorsed in principle by agencies such as SAMHSA. In the psychedelic context it covers education about risks and contraindications, screening, sober support during an experience, peer-support services, and integration support afterward. This site's contribution is educational information about reflection after an experience; it does not provide instructions on obtaining, testing, dosing, or using psilocybin.

Substance & pharmacology

Microdosing (Sub-perceptual dosing)#: The practice of taking psychedelics in amounts intended to be below the level of noticeable effects, usually on a repeating schedule over weeks. It emerged as a cultural practice in the 2010s and is now studied in its own right. Self-reports describe improved mood, focus, or creativity, but placebo-controlled studies have mostly not found benefits beyond placebo (for example Szigeti et al., 2021; Cavanna et al., 2022), and a 2022 systematic review rated much of the evidence as at high risk of bias. Described here as a research and cultural term; this site does not provide dosing schedules or use instructions.
Macrodosing (Heroic dose)#: A cultural term for a full-strength psychedelic experience, as opposed to microdosing. 'Heroic dose' is a related phrase coined by Terence McKenna for a deliberately intense solo experience; it is historical slang rather than a clinical category, and this site does not publish amounts to follow. Intense experiences of this kind are more often associated with ego dissolution and mystical-type experiences, and also with challenging experiences, which is why clinical research relies on screening, preparation, and trained monitors. Educational vocabulary only, not use guidance.
Psilocybin (4-PO-DMT)#: A naturally occurring tryptamine found in more than 200 mushroom species, most of them in the genus Psilocybe. It is a prodrug: the body converts it to psilocin, the active compound. Psilocybin is a controlled substance in most countries and Schedule I in the United States. A small number of regulated programs exist — Oregon's licensed psilocybin services (operating since 2023), Colorado's regulated natural-medicine program, where the first healing centers were licensed in 2025, and case-by-case access through Canada's Special Access Program. As of September 2026, no psilocybin medicine is approved by the US FDA; late-stage trials in treatment-resistant depression have reported results and a regulatory application is in progress. Other active research areas include end-of-life distress and alcohol use disorder.
Psilocin (4-HO-DMT)#: The active compound produced when the body removes a phosphate group from psilocybin. Psilocin crosses the blood–brain barrier and acts mainly as an agonist at serotonin 5-HT2A receptors, which is thought to underlie the psychedelic effects (reviewed in Nichols, 2016). It is less chemically stable than psilocybin and oxidizes readily, one reason mushroom potency varies and declines with storage.
Threshold dose (Museum dose)#: A pharmacology term for the smallest amount of a substance at which a noticeable effect begins. In psychedelic culture, 'threshold' and 'museum dose' describe experiences at the low end of the perceptible range, in contrast to microdosing (intended to be imperceptible) and full-strength experiences. Where the threshold lies varies with the individual, the material, and its potency, which in mushrooms is highly variable. Described here conceptually; this site does not publish amounts or dose bands.
Tolerance (psilocybin) #: The rapid reduction in response that follows repeated use of classical psychedelics. Tolerance to psilocybin develops quickly and is shared across psilocybin, LSD, and mescaline (cross-tolerance); it is associated with reduced signaling at serotonin 5-HT2A receptors and subsides over days (reviewed in Nichols, 2016). It is one reason these compounds are not considered to produce compulsive use. Described as a pharmacological phenomenon; this site does not recommend dose spacing or repeat use.