Who Should Not Use Psilocybin

Contraindications for Psilocybin

A contraindication is a condition or circumstance that makes a treatment inadvisable — either because it increases risk of harm or because it is likely to produce a worse outcome than doing nothing. Understanding contraindications is essential harm reduction for anyone considering psilocybin.

This page reflects what is known from clinical research and the harm reduction literature. It is not a substitute for medical advice. If you have any of the conditions listed here, consult a physician familiar with psychedelic medicine before proceeding.

Hard Contraindications

These are conditions where the risk is serious enough that psilocybin should not be used without direct medical supervision and specialist sign-off. Most clinical trials exclude participants with these conditions entirely.

Personal or Family History of Schizophrenia or Psychosis

Psilocybin can trigger or exacerbate psychotic episodes in people with underlying vulnerability. Schizophrenia involves a dysregulation of dopamine and serotonin systems that psychedelics interact with directly. Even a single moderate dose can precipitate a first psychotic break in a person with genetic vulnerability who has no prior psychiatric history.

This is the most important contraindication. The risk applies to:

• A personal diagnosis of schizophrenia or schizoaffective disorder
• A personal history of psychotic episodes (even if resolved)
• A first-degree relative (parent, sibling, child) with schizophrenia — this indicates genetic vulnerability even if you have not personally been diagnosed

Bipolar I Disorder

Psilocybin can trigger manic episodes in people with Bipolar I. Mania following psychedelic use can be severe, prolonged, and dangerous. People with Bipolar II have lower risk but should proceed only with psychiatric guidance.

Active Lithium Use

Lithium combined with psychedelics — including psilocybin — has been associated with seizures. This is a hard contraindication regardless of the reason lithium is prescribed. Do not use psilocybin while on lithium. Tapering lithium to use psilocybin requires psychiatric supervision and careful timing.

Active MAOI Use

Monoamine oxidase inhibitors (MAOIs) — including phenelzine, tranylcypromine, selegiline, and the RIMA moclobemide — dramatically potentiate psilocybin's effects in unpredictable and dangerous ways. The combination can produce extreme intensity, cardiovascular stress, and serotonin toxicity. This is a hard contraindication.

Note: Some reversible MAOIs (RIMAs) at low doses have been used in combination protocols in research settings, but this is never appropriate outside of clinical supervision.

Pregnancy and Breastfeeding

No human safety data exist for psilocybin in pregnancy. Animal studies suggest potential risks. Until safety data exist, psilocybin should not be used during pregnancy or while breastfeeding.

Significant Cautions

These conditions do not necessarily preclude psilocybin use but require careful medical evaluation, disclosure to your facilitator, and in some cases specialist sign-off.

Cardiovascular Disease

Psilocybin causes transient increases in blood pressure and heart rate, typically peaking 60–90 minutes after ingestion and resolving within 2–3 hours. For most healthy people this is not clinically significant. For people with:

• Coronary artery disease
• History of heart attack or stroke
• Uncontrolled hypertension
• Arrhythmias
• Significant valvular disease

...the cardiovascular load of a high-dose psilocybin session may pose elevated risk. Medical evaluation is required. Some people with well-controlled cardiac conditions proceed safely with lower doses and close monitoring; others should not proceed at all. This is an individual clinical determination.

Epilepsy and Seizure Disorders

Psilocybin is not known to lower seizure threshold (unlike some other substances), but the evidence in people with active seizure disorders is limited. Proceed only with neurologist consultation.

Severe Liver Disease

Psilocybin is metabolized primarily by the liver. Severe hepatic impairment may alter pharmacokinetics in unpredictable ways. Mild to moderate liver disease is generally not a contraindication but should be disclosed.

Current Suicidal Ideation with Plan or Intent

Active suicidal ideation with a specific plan or intent is a contraindication for psilocybin sessions outside of a clinical setting with a full mental health team present. Psilocybin can surface intense emotional material, and in the absence of adequate containment, this creates real risk.

Passive suicidal ideation (thoughts without plan or intent) is not necessarily a contraindication — many clinical trials have enrolled people with passive ideation. This requires honest clinical assessment. Disclosure to your facilitator is essential.

Severe Personality Disorders

People with borderline personality disorder (BPD), narcissistic personality disorder, or antisocial personality disorder can have profoundly destabilizing experiences with psilocybin. This is not an absolute contraindication, but the therapeutic container and facilitator experience required is substantially more demanding. Proceed only with experienced clinical guidance.

Medication Interactions

See Drug Interactions for a complete list. Summary of the most clinically important:

| Medication Class | Interaction | Risk Level | |-----------------|-------------|------------| | MAOIs | Potentiation, serotonin toxicity | Hard contraindication | | Lithium | Seizure risk | Hard contraindication | | SSRIs/SNRIs | Blunted effects, possible serotonin effects | Caution | | Tramadol | Serotonin syndrome risk | Significant caution | | Antipsychotics (typical) | Blunted effects, unpredictable interaction | Caution | | Beta blockers | May reduce anxiety response; mild blunting | Minor | | Cannabis (THC) | Intensifies and extends experience; anxiety risk | Caution |

Psychiatric History: Nuanced Situations

Bipolar II

People with Bipolar II have hypomania rather than full mania. The risk of psilocybin triggering a manic episode is lower than in Bipolar I but not zero. Proceed only with psychiatric evaluation and facilitator disclosure. Many people with well-managed Bipolar II have undergone psilocybin therapy safely; the individual risk profile matters enormously.

PTSD with Active Trauma Processing

Active, destabilized PTSD — where the person is in acute distress, frequently triggered, or in the middle of intensive trauma processing in therapy — is not an ideal time for psilocybin. Stability before the session allows for better outcomes. This is timing guidance, not a permanent contraindication.

Anxiety Disorders

Anxiety disorders are not a contraindication. In fact, psilocybin has shown positive results for anxiety in multiple studies. However, people with severe anxiety or panic disorder should work with an experienced facilitator, start with a lower dose, and invest heavily in preparation.

Depression with Passive Suicidal Ideation

Depression, including treatment-resistant depression, is one of the primary indications for psilocybin therapy. Passive suicidal ideation (thoughts without plan) is common in this population and has been permitted in most clinical trials. Disclosure to the facilitator is essential; additional support structures may be warranted.

Age Considerations

Most clinical trials have enrolled adults aged 21–65. Psilocybin in adolescents is not well-studied, and the developing brain may respond differently. Use in people under 21 is not recommended outside of specialist clinical settings.

For adults over 65, psilocybin has been studied in end-of-life populations with generally positive safety profiles. Cardiovascular screening is more important in older populations.

What to Tell Your Facilitator

Ethical facilitators will conduct a thorough intake screening that covers all of the above. You should be honest about:

• Complete psychiatric history, including family history
• All medications, supplements, and substances used regularly
• Any history of psychotic episodes, even brief or undiagnosed
• Cardiovascular history
• Current emotional stability
• Any previous difficult psychedelic experiences

A facilitator who does not ask these questions is not conducting adequate screening. A facilitator who pressures you to proceed despite concerns you have raised is exhibiting a red flag.

Providing false information to a facilitator to proceed with a session you know is contraindicated places you and the facilitator at serious risk. The intake process is not a barrier to overcome — it is a safety system that exists for your protection.

Medical Resources

If you are unsure whether a condition you have is a contraindication:

• MAPS psychiatrists offer consultations for people with complex medical/psychiatric histories considering psychedelic therapy
• Your prescribing physician — if you have an open-minded prescriber, an honest conversation about your interest in psilocybin therapy is increasingly possible as clinical awareness grows
• Zendo Project and Fireside Project can help connect people with harm reduction counselors who can assess individual situations