Psilocybin retreats

Safety facts, with sources

What published research, regulators and harm-reduction services say about psilocybin. These are the questions to put to any centre. Nothing here makes any centre safe, and none of it is medical advice.

• Lithium: seizure riskSerious risk

  An analysis of online reports found that 47% of 62 reports of lithium taken with a classic psychedelic (such as psilocybin or LSD) involved seizures and 39% involved medical attention, while none of 34 lamotrigine reports did. The authors provisionally concluded psychedelic use may pose a significant seizure risk for people on lithium. (Pharmacopsychiatry, 2021)

• Oregon bars recent lithium usersSerious risk

  Oregon's required Client Information Form asks whether the client has taken lithium in the last 30 days; a yes answer means the client may not participate in an administration session. (Oregon Health Authority, Public Health Division, 2026)

• Psychosis and severe psychiatric historySerious risk

  Published research safety guidelines recommend excluding volunteers with a personal or family history of psychotic disorders or other severe psychiatric disorders, and note prolonged psychoses triggered by hallucinogens are less common than acute distress. Oregon's Client Information Form bars anyone who has ever been diagnosed with or treated for active psychosis. (Journal of Psychopharmacology, 2008; Oregon Health Authority, Public Health Division, 2026)

• Bipolar disorderSerious risk

  In an international survey of 541 people with self-reported bipolar disorder who had used psilocybin, 32.2% described new or increasing symptoms after trips, prominently manic symptoms, sleep problems and anxiety; 3.3% used emergency medical services. The authors say bipolar symptoms may emerge or intensify after psilocybin use. (Journal of Psychopharmacology, 2023)

• Tricyclic antidepressants and lithium may intensify effectsWorth knowing

  A small retrospective questionnaire study (10 people using LSD, not psilocybin) found chronic tricyclic antidepressant or lithium use was associated with subjectively stronger physical, hallucinatory and psychological responses, while chronic MAOI use was associated with weaker responses. (Behavioural Brain Research, 1996)

• SSRIs and SNRIs can blunt effectsWorth knowing

  In a survey of 611 reports of taking mushrooms with an antidepressant, the probability of weaker than expected effects was 0.47 for SSRIs, 0.55 for SNRIs and 0.29 for bupropion, and reduced effects may persist up to 3 months after stopping an SSRI or SNRI. An older study found 28 of 32 people (88%) on serotonin reuptake-inhibiting antidepressants for over 3 weeks reported decreased or virtually eliminated LSD effects. (Journal of Psychopharmacology, 2023; Neuropsychopharmacology, 1996)

• Antidepressant interactions: serotonin syndrome risk is lower than with ayahuascaWorth knowing

  A review of serotonin toxicity concluded that serotonergic psychotropics without MAOIs are low risk in combination with psychedelics that also do not contain MAOIs, such as psilocybin; the main danger arises when an MAOI is involved. (Psychopharmacology (Berl), 2022)

• Blood pressure and heart rateWorth knowing

  NIDA states that psilocybin typically raises blood pressure and heart rate, which may be dangerous for people with heart conditions. A 2024 meta-analysis of psychedelic trials found an increased risk of elevated heart rate and systolic and diastolic blood pressure at all dose ranges during the acute phase. (National Institute on Drug Abuse (NIH); Psychiatry Research, 2024; EMCDDA (now EUDA), via Internet Archive snapshot 2024-06-18)

• Challenging experiences outside supervised settingsWorth knowing

  In a survey of 1,993 people describing their worst psilocybin mushroom experience, 11% put themselves or others at risk of physical harm, 2.6% behaved aggressively or violently, 2.7% received medical help, and 7.6% of those whose experience was over a year earlier sought treatment for enduring psychological symptoms. Risk rose with dose and with absence of physical comfort and social support. (Journal of Psychopharmacology, 2016)

• Unsupervised use and risky behaviourWorth knowing

  NIDA notes that health risks are greater when psilocybin is taken unsupervised and outside clinical supervision, including dangerous behaviour such as driving or walking in traffic while impaired. (National Institute on Drug Abuse (NIH))

• Adverse events in the COMP360 phase 2b trialWorth knowing

  In the NEJM phase 2 trial of a single dose of COMPASS's synthetic psilocybin for treatment-resistant depression (233 participants), adverse events occurred in 179 participants (77%), including headache, nausea and dizziness, and suicidal ideation or behaviour or self-injury occurred in all dose groups. (New England Journal of Medicine, 2022)

• Oregon's mandatory client screening questionsWorth knowing

  Before any Oregon administration session, the client must complete a Client Information Form with a facilitator, answering yes/no questions on lithium use, current treatment for medical or mental health conditions, mushroom allergy, medications, thoughts or history of harming self or others, active psychosis and pregnancy or breastfeeding. Current thoughts of harming self or others, lithium in the last 30 days, or a history of active psychosis rule out a session; clients who are pregnant or breastfeeding must be told the risks are unknown. (Oregon Health Authority, Public Health Division, 2026)

• No quality control of truffle ceremoniesSerious risk

  The Trimbos Institute's DRUGSinfo warns that nobody checks the quality of truffle or mushroom ceremonies, including intake, aftercare or the number of sober people present, and that a truffle ceremony can be dangerous for people who take medication or have psychological complaints. (DRUGSinfo (Drugs Infolijn), Trimbos-instituut)

• Psychosis riskSerious risk

  DRUGSinfo states that mushrooms and truffles can trigger or worsen psychosis, mainly in people who are susceptible, for example because it runs in the family or they have had a psychosis before. (DRUGSinfo (Drugs Infolijn), Trimbos-instituut)

• Strength varies between packsWorth knowing

  DRUGSinfo notes that smartshop staff can advise on truffle strength, but the strength of truffles is known to vary from pack to pack. (DRUGSinfo (Drugs Infolijn), Trimbos-instituut)

• Ceremonies are not therapyWorth knowing

  DRUGSinfo states that advertising ceremonies as treatment for mental health problems is not allowed and not correct, that evidence is far too limited, and that many people have more complaints after a ceremony. (DRUGSinfo (Drugs Infolijn), Trimbos-instituut)

Programme lengths and published prices