Psilocybin Contraindications: Who Natural Medicine Is Not a Good Fit For

Most of what gets written about psilocybin therapy is about who it helps. This page is the other half: who it isn’t for, at least not right now.

That’s a useful thing to be able to read for yourself. People spend weeks deciding whether to make a call, and a fair number of them are carrying something — a medication, a diagnosis, a family history — that would have answered the question in thirty seconds if anyone had told them what actually matters. So here it is, laid out in the order a facilitator would think about it.

This is general education about how licensed programs screen, not a screening itself and not medical advice. Nobody can clear you or rule you out from a web page. But you can get most of the way to an informed conversation, and you’ll know which parts of your history to bring up first.

There’s also a one-page version of this list (PDF) if you’d rather print it, or send it to someone who’s weighing this.

How to read this list

Exclusions fall into two very different categories, and conflating them causes a lot of unnecessary discouragement.

Firm rule-outs are situations where responsible programs decline, full stop, for as long as the situation holds. Some are legal. Most are safety. A few of them are temporary — pregnancy ends, a medication can be changed, an acute crisis resolves — but while they apply, the answer is no.

Situations that require a real conversation are the larger group, and they are not rejections. They’re the things that make screening longer, sometimes involve your prescriber or a specialist, and occasionally end in not yet rather than no. Most people who see themselves on this second list are still candidates. They just need a more careful setup than average.

Firm rule-outs

Under 21. Colorado’s Natural Medicine Health Act sets 21 as the floor for regulated natural medicine services. There is no exception, no parental consent pathway, and no clinical judgment involved. If you’re 20, the answer is next year.

Schizophrenia, schizoaffective disorder, or another primary psychotic disorder. A psilocybin experience can temporarily produce thought disorganization, altered perception, and a blurred sense of where the self ends — features that overlap with psychosis. In someone with an underlying psychotic illness, that can worsen symptoms or extend into something that outlasts the session.

Bipolar I, or any history of mania or a psychotic episode. This holds regardless of what the episode was attributed to at the time — including a manic or psychotic episode triggered by a substance, a medication, or postpartum. A 2026 systematic review and meta-analysis in Molecular Psychiatry found rates of psychedelic-associated hypomania or mania ranging from about 6% in controlled psilocybin trials for depression up to 30% in naturalistic studies of people with bipolar disorder. A single prior manic episode is the clearest predictor anyone has.

Current psychosis or mania, whatever the diagnosis says. If symptoms are active now, the diagnosis on file doesn’t change the answer.

Active suicidality with a plan or intent, or a recent attempt. This isn’t a judgment about the person, and it isn’t permanent. It’s about matching the intervention to the moment: acute crisis calls for stabilization and support, not an elective full-dose experience. Psilocybin therapy can absolutely be part of a longer arc for someone with a history of suicidality — we’ve written about that in more detail — once the acute phase has passed.

Pregnancy or breastfeeding. There is essentially no safety data in these populations, and no responsible reason to be the one generating it.

Lithium. This is the most serious documented drug interaction in the space. In a Johns Hopkins analysis of online psychedelic experience reports, 47% of 62 reports involving lithium plus a classic psychedelic described a seizure — compared with none of 34 reports involving lamotrigine. Self-reported data has real limits, but the signal is strong enough that clinical guidance treats lithium as an absolute contraindication. Lithium is also, for many people, the medication holding a mood disorder stable — so this is not a “taper and proceed” item. Whether to change it is a decision between you and your prescriber, made on its own merits, and never for the purpose of qualifying for a session.

MAOIs. Monoamine oxidase inhibitors — prescription (phenelzine, tranylcypromine, isocarboxazid, selegiline) and botanical (Syrian rue, the B. caapi in ayahuasca) — can potentiate psilocybin unpredictably and carry risk of hypertensive and serotonergic reactions.

Unstable cardiovascular disease. Psilocybin transiently raises heart rate and blood pressure over several hours. Recent heart attack or stroke, unstable angina, significant arrhythmia, clinically important valvular disease, or uncontrolled hypertension all make that burden unacceptable. Note the word unstable — well-controlled cardiac history is on the other list.

Uncontrolled seizure disorder. Active, poorly controlled epilepsy is a rule-out. Remote or well-controlled seizure history is a conversation.

Anyone who cannot give free, informed consent. Two versions of this. The first is capacity — dementia or cognitive impairment significant enough that a person can’t meaningfully weigh what they’re agreeing to. The second is coercion: participation ordered by a court, required by an employer, or made a condition of something else. Consent that isn’t freely given isn’t consent, and a session someone didn’t choose is a bad session on every dimension that matters.

Situations that require a real conversation

A first-degree relative with schizophrenia or bipolar I. This is the most weighted item on this list, and programs genuinely differ on it — some treat it as a hard stop, others as a case-by-case decision with unusually thorough screening. Familial vulnerability to bipolar illness shows up as a risk factor in the observational literature, so the conversation covers the specifics of the relative’s diagnosis, your own history of mood elevation or unusual perceptual experiences, and whether there’s a prescriber to involve. Where programs do proceed, it’s typically with a conservative setup — and never as a formality. Worth asking any program directly how they handle it.

Bipolar II without psychotic features. More nuanced than bipolar I and increasingly studied, but most clinical trials still exclude it and the evidence base is thin. Requires psychiatric involvement and, realistically, a higher tolerance for uncertainty than most decisions in this process.

Daily or dependent benzodiazepine use. Occasional as-needed use is straightforward — it’s typically held on the day, since benzodiazepines blunt the experience. Daily use is a different problem: holding it abruptly risks withdrawal, and withdrawal risks seizures. That needs a prescriber-supervised plan well before a session date exists, not a decision made the week of.

Heavy alcohol or stimulant use. Substances that require medically supervised withdrawal — alcohol, benzodiazepines, opioids — need detox handled first. Regular high-intensity stimulant use also warrants cardiovascular evaluation before anyone adds several hours of elevated heart rate.

Passive suicidal ideation without plan, or a psychiatric hospitalization in the past 6–12 months. Neither is disqualifying. Both change what adequate support looks like, and both usually mean coordinating with whoever is already treating you.

Dissociative disorders, severe complex PTSD, borderline personality disorder, or marked emotion dysregulation. Psilocybin surfaces material forcefully and reduces the usual defenses against it. If a person’s baseline capacity to tolerate intense emotion is already stretched, an unprepared session can leave them worse off than it found them. This is one of the more common not yet answers — and often the productive answer is a course of skills work first, then revisiting. As a DBT-certified program, that’s something we can build directly rather than refer out.

Controlled hypertension or cardiac history, with cardiology clearance. Manageable, and common. It just means a specialist signs off before a date is set.

Remote or well-controlled seizure history. Individual assessment, including which anticonvulsant you’re on.

A prior difficult psychedelic experience, or HPPD. A hard trip in the past isn’t predictive of a hard trip now — set, setting, dose, and support are wildly different in a licensed session than in whatever the original context was. But it’s worth understanding what happened and why. Persistent perceptual changes after prior use are a more serious flag.

Medical complexity for a long session day. An administration session can run up to seven hours, with limited food beforehand and limited mobility during. Diabetes, significant mobility limitations, incontinence, frailty, and severe liver disease all belong in the medical review — not because they’re disqualifying, but because a session has to be planned around them.

An eating disorder in an acute phase. Medical stabilization comes first. Fasting and a long unstructured day are the wrong environment for an acutely unwell body.

No aftercare, no ride, no integration plan. Practical and non-negotiable in substance, even though it’s easy to fix. You cannot drive afterward, so someone has to take you home. And the weeks following a session are where most of the actual change gets consolidated — which is why integration is part of the arc rather than an upsell. Arriving with no plan for the days after is a real risk factor, not a logistics footnote.

Motivation that belongs to somebody else. A partner who thinks it would fix things, a family member who read an article. Different from a court order — this isn’t a capacity problem and it isn’t automatic — but it’s worth naming out loud in preparation, because sessions driven by someone else’s hope tend to go poorly. The question worth sitting with: if the person pushing for this stopped pushing, would you still want it?

Medications: the most common source of confusion

Only lithium and MAOIs are firm medication rule-outs. Almost everything else is a timing and coordination question, and people talk themselves out of the whole thing over medications that were never the problem.

SSRIs and SNRIs downregulate the receptor psilocybin acts on, so the main risk is a blunted, disappointing experience rather than a dangerous one. Many protocols taper beforehand; sometimes staying on is the right call — we’ve written about that question in depth. Mirtazapine directly opposes psilocybin’s mechanism and is usually tapered. Tricyclics are handled similarly, with added attention to blood pressure. Antipsychotics block the same receptors and largely cancel the experience out — and more importantly, the reason someone is on one is usually itself the relevant question. Tramadol is both serotonergic and lowers the seizure threshold; it needs sorting out in advance. Stimulants are typically held on the day.

The rule underneath all of this: never start, stop, or adjust a psychiatric medication on your own, and never taper something in order to become eligible. Every one of these decisions belongs to your prescriber, on its own clinical merits.

Things people worry about that aren’t rule-outs

Being on an antidepressant. Being in therapy already. Being older — age itself isn’t a contraindication, and end-of-life distress is among the strongest indications in the literature. Not having a diagnosis; Colorado’s program doesn’t require one. Having tried psilocybin recreationally before. Being nervous about it, which is close to universal and not a bad sign.

Also worth saying: honest disclosure during screening is the single thing that makes a session safe. A screening you got through by leaving something out isn’t a screening you passed.

If something here applies to you

Very little on this page is permanent. Medications change. Acute phases resolve. Support systems can be built, and skills can be learned. The realistic outcomes are yes, yes with a more careful setup, and not yet — and the third one usually comes with a description of what would need to be different.

The wrong move is to decide alone, in either direction. If something on the firm list applies, that’s genuinely settled for now, and a program that waves it through is telling you something about how it screens everyone else. If something on the second list applies, it’s a conversation — and it’s the conversation licensed facilitators have every week.

For how screening works in practice, see our safety and screening page. For thinking through readiness and timing rather than safety, is psilocybin therapy right for you covers the other side of the question.

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Not sure where you land? Get in touch — a free 15-minute consultation is enough to sort out most of this, including the answer that it isn’t the right time. You can also read about what happens in a session, how to prepare, or Colorado’s Natural Medicine Health Act.