Ketamine vs Psilocybin Therapy in Canada

Both ketamine and psilocybin are used in psychedelic-assisted therapy in Canada — but through fundamentally different legal pathways. Ketamine is a Health Canada-approved medication, prescribed off-label for depression, post-traumatic stress disorder (PTSD), anxiety, OCD, and chronic pain through routine clinical channels. Psilocybin is a Schedule III controlled substance with no Health Canada psychiatric approval; clinical access requires a physician-submitted Special Access Program (SAP) application or a clinical trial. The mechanisms differ, the indications overlap partially, and the access realities differ dramatically. This guide compares them for Canadian patients and clinicians weighing the choice.

Key takeaways

• Ketamine acts on the glutamate system via NMDA (N-methyl-D-aspartate) receptor antagonism; psilocybin acts on the serotonin system via 5-HT2A agonism. Both produce neuroplasticity but through different pathways.
• For Canadians today, ketamine is immediately accessible via off-label prescribing and Spravato (Health Canada approved). Psilocybin is access-constrained — SAP applications declined to roughly 16% overall approval rate as of mid-2025.
• The strongest evidence overlap is in treatment-resistant depression. Psilocybin has additional evidence in end-of-life distress, alcohol use disorder, and tobacco cessation; ketamine has additional evidence in chronic pain (CRPS, neuropathic).
• Treatment courses differ: ketamine = 4–8 sessions over 2–4 weeks with maintenance; psilocybin = typically 1–2 dosing sessions with extensive preparation and integration.
• Cost: ketamine CAD $375–$1,400/session; psilocybin (when SAP-approved) CAD $2,500–$6,500 per program. Ketamine is sometimes covered by private insurance; psilocybin is currently not covered by any Canadian insurer.

Patients considering ketamine-assisted therapy can book a free information call to discuss eligibility and which pathway may fit their situation.

Why patients ask this question

The two compounds get conflated in public conversation. Both are sometimes called "psychedelics." Both are used in psychedelic-assisted therapy frameworks. Both have rapid antidepressant evidence in treatment-resistant depression. Both produce altered states.

Beyond those surface similarities, the differences are substantial. Mechanism, regulatory status, access, treatment course, session experience, cost, and indication breadth all diverge. The honest answer to "which is better?" is: it depends on your diagnosis, your access constraints, your timeline, your prior treatment history, and your tolerance for the specific kind of altered-state experience each produces. There is no universal "better" between the two — there is only fit.

How they work — different brain systems

Ketamine acts primarily as an NMDA receptor antagonist. Blocking NMDA receptors on inhibitory interneurons triggers a downstream surge of glutamate, AMPA receptor activation, and BDNF release that drives synaptogenesis — the formation of new neural connections within 24 to 72 hours of a dose (Kang et al., 2022). The classical psychedelic — psilocybin — operates through a different receptor system: 5-HT2A serotonin receptor agonism, which produces measurable default mode network changes alongside reduced amygdala blood flow correlating with antidepressant response (Carhart-Harris et al., 2017). A 2023 review in Neuropsychopharmacology documented that "psychedelics promote dendritogenesis, spinogenesis and synaptogenesis" via 5-HT2A activation (Calder & Hasler, 2023).

The two converge on neuroplasticity as a downstream effect — what Aleksandrova and Phillips (2021) call the "psychoplastogen" framework: different pharmacological paths to similar synaptic outcomes (Aleksandrova & Phillips, 2021). Both increase AMPA activation and BDNF/TrkB signalling. Both promote structural changes in pyramidal neurons of the prefrontal cortex.

But the routes matter clinically. Ketamine's onset is faster (hours); psilocybin's experience is longer (5–7 hours per dosing session) and the durability evidence from a single high-dose session may extend further. Drug-interaction profiles differ — psilocybin's serotonergic mechanism creates theoretical interaction concerns with SSRIs, MAOIs, and lithium that ketamine does not raise to the same degree.

What conditions does each treat?

The strongest evidence overlap is treatment-resistant depression. Outside that, the two diverge.

The clinical picture: ketamine has the broader indication footprint for routine psychiatric and pain care; psilocybin has unique evidence in end-of-life distress, alcohol use disorder, and tobacco cessation that ketamine does not have. For a patient with treatment-resistant depression, both have evidence; for a patient with chronic pain, ketamine is the clearly better-evidenced option; for a patient with terminal illness and existential distress, psilocybin (when accessible) is the better-evidenced option.

Regulatory status — the largest practical difference

This is where Canadian patients face the starkest divergence.

Ketamine is a Schedule I controlled substance under the CDSA, legally permitted for medical use when prescribed by a physician or nurse practitioner. Health Canada has approved ketamine as an anaesthetic; psychiatric use is off-label, a legal and common practice in Canadian medicine. Spravato (intranasal esketamine) is Health Canada-approved for treatment-resistant MDD as of May 2020. Provincial physician colleges (CPSA, CPSM, CPSO, CPSBC) regulate where IV ketamine can be administered; community settings are permitted for IM/oral/sublingual/intranasal routes.

The practical effect: a Canadian patient diagnosed with treatment-resistant depression (TRD) today can access ketamine through dozens of clinics across the country within weeks of inquiry. The pathway is well-established.

Psilocybin is a Schedule III controlled substance under the CDSA. Health Canada has issued no psychiatric approval. Clinical access requires either:

1. A physician-submitted Special Access Program (SAP) application for an individual patient, approved on a case-by-case basis, or
2. Enrollment in a Health Canada-authorized clinical trial

The SAP framework is governed by Health Canada's Notice to Stakeholders. Eligible indications include treatment-resistant MDD, end-of-life distress (psilocybin), and PTSD (MDMA). The prescribing physician submits the application; psychologists and psychotherapists do not apply directly.

SAP approval rates have declined sharply. PsyCan reported in September 2025 that approval rates fell to roughly half the prior year's rate under the Carney government, with cumulative approvals reaching 301 by mid-2025 against an overall approval rate of 16% since 2020. Wait times have grown materially.

The practical effect: a Canadian patient considering psilocybin therapy today faces an access pathway with months of preparation, no guarantee of approval, and limited geographic availability of qualified prescribers. For patients who can access psilocybin via SAP, the clinical experience is well-established; for the majority who cannot, the question is largely theoretical until and unless regulatory access expands.

Treatment course — different rhythms

The cadence is meaningfully different. Ketamine fits a "course of clinical sessions" model patients are familiar with from infusion clinics. Psilocybin operates more like a high-investment single-event model with extensive scaffolding around the dose.

The session experience

Ketamine session. Sub-anaesthetic dose administered IV, IM, sublingually, or via Spravato nasal spray. Acute experience lasts 45 to 90 minutes. Patients commonly describe altered time perception, mild visual or auditory shifts, an emotional softening, and a sense of distance from habitual thought patterns. Dissociation is the technical term. The clinical team is present throughout; vitals are monitored continuously. Resolves before discharge.

Psilocybin session. Higher-dose oral psilocybin (typically 25 mg synthetic) in a structured clinical setting. Experience lasts 5 to 7 hours. Patients typically wear eyeshades and listen to curated music to deepen the inward experience. Emotional surfacing is more pronounced. Visual and perceptual changes are more intense. The mystical-type experience that emerges in some sessions has been shown to predict therapeutic outcome — Roseman et al. (2018) found that "oceanic boundlessness" intensity during psilocybin sessions significantly predicted antidepressant outcomes (Roseman et al., 2018). Murphy et al. (2022) showed that pre-session therapeutic alliance strength predicted both the quality of the acute experience and final depression scores (Murphy et al., 2022).

Both experiences require integration psychotherapy. Both happen in supervised settings. They are not interchangeable in subjective character: the psilocybin experience is more demanding, longer, and emotionally weightier than the ketamine session for most patients.

Safety profile — both well-tolerated in clinical contexts

Both have well-established safety profiles when administered with proper screening in supervised settings.

Ketamine. The pooled safety analysis across 205 IV infusions in 97 TRD patients found ketamine "safe and well tolerated"; hemodynamic changes were transient; no persistent psychotomimetic effects (Murrough et al., 2015). Long-term concerns (bladder cystitis, hepatic effects) are linked to high-frequency, high-dose recreational exposure rather than therapeutic clinical dosing.

Psilocybin. Carbonaro et al. (2016) surveyed 1,993 individuals about challenging psilocybin experiences: "Despite challenging experiences, 84% reported benefit; only 2.7% required medical help; adverse effects are greater in uncontrolled versus supervised clinical settings" (Carbonaro et al., 2016). Psilocybin trials in clinical settings consistently report excellent safety profiles when patients are appropriately screened.

Shared contraindications: active psychosis or schizophrenia spectrum disorder (absolute), uncontrolled cardiovascular disease, current pregnancy.

Ketamine-specific considerations: bladder/hepatic concerns at long-term high doses; less concern with serotonergic medication interactions.

Psilocybin-specific considerations: theoretical serotonin syndrome risk with MAOIs, possible interaction with lithium (seizure risk reported), generally tolerated alongside SSRIs but specific protocols vary.

Cost in Canada

Ketamine is sometimes covered; psilocybin is currently always self-pay in Canada. See Ketamine Therapy Cost in Canada and Insurance Coverage for Ketamine Therapy for ketamine specifics.

When ketamine vs. when psilocybin: a decision framework

These scenarios are illustrative. Treatment selection requires individual clinical assessment.

Patient needs treatment now and has failed two antidepressants → Ketamine. Immediately accessible through registered Canadian clinics. Spravato has the Health Canada TRD indication. Psilocybin requires SAP application with a 16% overall approval rate and significant wait times.

Patient has terminal illness and is experiencing existential distress → Psilocybin (if accessible via SAP). The strongest evidence base for this indication. Both Griffiths 2016 (JHU, n=51) and Ross 2016 (NYU, n=29) showed ~80% sustained benefit at 6-month follow-up. End-of-life distress has more reliable SAP approval rates than MDD. Ketamine has no equivalent evidence in this specific niche.

Patient presents with active suicidal ideation requiring rapid stabilization → Ketamine. Wilkinson 2018 meta-analysis documents rapid antisuicidal effect within 24 hours. The SAP timeline rules out psilocybin in acute presentations.

Patient has TRD AND comorbid chronic pain → Ketamine. The only option with evidence across both indications (Niesters et al., 2014). Psilocybin has no clinically meaningful chronic pain evidence.

Patient has TRD AND alcohol use disorder → Psilocybin (if accessible). Bogenschutz 2022 RCT showed 48% complete abstinence at 8 months versus 24% on active placebo. Ketamine has emerging but less robust AUD data.

Patient values treatment efficiency / time-to-response → Ketamine. Course completes in 2–4 weeks with response often within hours of first session.

Patient is on lithium or MAOIs → Ketamine has the cleaner drug-interaction profile. Psilocybin's serotonergic mechanism creates theoretical concerns with both classes; standard psilocybin SAP screening excludes these combinations.

Integration matters for both

Ketamine and psilocybin both produce a window of heightened neuroplasticity post-dose. The therapeutic question for both is whether structured psychotherapy during and after this window translates the experience into sustained behavioural change.

For ketamine, Wilkinson et al. (2017) showed that adding 12 weeks of CBT after a 4-session IV ketamine course extended antidepressant durability — relapse occurred in only 25% of responders by week 8 versus 55–89% in comparable open-label ketamine-only protocols. For psilocybin, integration is built into nearly every clinical protocol because the experience itself is more demanding and the durability claims (6–12 months from a single session) depend on the integration work that follows.

ATMA CENA's coordinated care model — designed primarily for ketamine-assisted psychotherapy (KAP) currently — is structured around this principle: trained therapists provide preparation and integration while the medical team handles the dosing infrastructure. The architecture would translate to psilocybin if and when broader access exists in Canada.

The Canadian regulatory landscape — what may change

Alberta was the first province to formally regulate psychedelic-assisted therapy (Mental Health Services Protection Regulation, January 2023; CAP June 2025 PAP guideline) — see ATMA CENA's regulatory position. The framework supports clinical research and SAP-context delivery within accredited facilities.

For ketamine specifically, the 2024–2026 period saw provincial physician colleges issue specific guidance: CPSA March 2026, CPSM January 2026, CPSBC interim August 2025. These frameworks are now mature.

For psilocybin, the regulatory picture is less stable. SAP approval rates have declined; class-exemption advocacy continues from PsyCan and similar bodies. The future depends on Health Canada policy decisions and whether commercial sponsors (Compass Pathways, Cybin, others) successfully complete Phase 3 trials and seek regulatory approval. As of May 2026, the SAP pathway remains the only route for individual Canadian patients outside clinical trials.

Frequently asked questions

Is ketamine or psilocybin better for depression? Both have evidence in treatment-resistant depression. Ketamine has the longer track record, broader access in Canada, and CANMAT third-line guideline status. Psilocybin has Phase 2/2b RCT evidence (Goodwin 2022 NEJM; Raison 2023 JAMA) and may have longer durability from a single high-dose session, but Canadian access via SAP is constrained. For most Canadian patients today, ketamine is the realistically accessible option.

Can I get psilocybin therapy in Canada legally? Only through Health Canada's Special Access Program (physician-submitted, case-by-case approval) or enrollment in an authorized clinical trial. Approval rates declined to roughly 16% overall as of mid-2025. Ketamine is the immediately accessible option for most Canadians.

What's the difference between ketamine and psilocybin in the brain? Ketamine acts on glutamate via NMDA receptor antagonism; psilocybin acts on serotonin via 5-HT2A receptor agonism. Both produce neuroplasticity downstream — synaptogenesis, BDNF release — but through different receptor systems. The "psychoplastogen" framework groups them as different paths to similar synaptic outcomes.

How long does each session last? Ketamine: 45 to 90 minutes for the acute experience; 90–120 minutes total clinic time (longer for Spravato — 2-hour observation required). Psilocybin: 5 to 7 hours for the acute experience.

Which has fewer side effects? Both are well-tolerated in clinical contexts with proper screening. Ketamine: dissociation, transient BP/HR elevation, mild nausea. Psilocybin: anxiety/HRT during session ("challenging experience"), longer experience requires more sustained therapeutic support. Carbonaro 2016 documented that 84% of psilocybin users reported benefit even from challenging experiences in supervised settings.

Can I combine ketamine and psilocybin? Not in the same session, and combining them sequentially is not standard practice in any Canadian clinical protocol. They have different mechanisms and clinical pathways. Discuss any cross-substance treatment plans with a qualified prescribing physician.

Is psilocybin addictive? Psilocybin has very low addiction potential; it is not associated with compulsive use patterns. It has a different abuse profile than ketamine. Active substance use disorder is a contraindication for both treatments.

Does ATMA CENA offer psilocybin therapy? ATMA CENA operates within Canadian regulatory frameworks. ATMA CENA's clinical model is designed to support psilocybin and MDMA when SAP access is established for individual patients, and the broader structure (preparation + dosing + integration) translates to either substance. The day-to-day clinical work in 2026 is primarily ketamine-assisted therapy.

Which costs more? Comparable per program. Ketamine: CAD $1,530–$8,400 for an ATMA CENA KAT program. Psilocybin (when SAP-approved): CAD $2,500–$6,500 for a typical full program (e.g., TheraPsil range). Ketamine is sometimes covered by private insurance; psilocybin is currently not covered by any Canadian insurer.

What if I want to wait for more research on psilocybin before deciding? This is a reasonable position for many indications. Phase 3 psilocybin trials are ongoing internationally. Health Canada-approved access may broaden over the next 3 to 5 years. For patients with severe untreated depression or active suicidal ideation, however, the wait is non-trivial; ketamine often makes more sense as an immediately accessible bridging option.

Sources

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Related articles in this cluster

• Ketamine Therapy in Canada
• What Is Ketamine Therapy?
• How to Qualify for Ketamine Therapy in Canada
• Ketamine Therapy for Depression
• Does Ketamine Therapy Get You High?
• Ketamine Therapy FAQs
• Insurance Coverage for Ketamine Therapy
• ATMA CENA's Position on Psychedelic Regulation
• Psychedelics 101

Last updated: 2026-05-05