How Many Ketamine Treatments Do I Need?

The honest answer is it depends. The acute course supported by the largest evidence base — CANMAT 2021's recommendation for IV racemic ketamine in treatment-resistant depression — is 4 to 8 sessions over 2 to 3 weeks, typically twice weekly. For Spravato, the Health Canada-approved induction protocol is twice-weekly for 4 weeks (8 sessions), then weekly through weeks 5–8. Beyond the acute course, maintenance is individualized: some patients need monthly boosters, some need every-other-week dosing for several months, some sustain remission with no further dosing, and some will need ongoing maintenance indefinitely. SUSTAIN-1 and SUSTAIN-2 (the long-term Spravato trials) showed that continued dosing extends time to relapse compared with stopping. This article walks through what the evidence actually says, how ATMA CENA's program tiers map to typical courses, what predicts needing more sessions, and when to switch or stop.

Key takeaways

• Acute course: CANMAT 2021 recommends 4–8 IV ketamine sessions over 2–3 weeks for TRD; twice-weekly is the typical schedule (Singh 2016 showed twice-weekly non-inferior to thrice-weekly).
• Spravato induction: Health Canada protocol is twice-weekly for 4 weeks (8 sessions), then weekly through weeks 5–8.
• Maintenance: highly individualized. SUSTAIN-1 (Daly 2019) showed continued Spravato dosing extends time to relapse versus stopping; SUSTAIN-2 (Wajs 2020) demonstrated up-to-1-year safety of continued dosing.
• Predictors of needing more sessions: chronicity of TRD, comorbid PTSD/anxiety/chronic pain, concurrent benzodiazepines (which may attenuate effect — Andrashko 2020).
• When to stop or switch: no response after 4–6 acute infusions warrants re-evaluation — diagnosis review (e.g., undetected bipolarity), route or molecule change (IV ↔ Spravato), or alternative (ECT comparable per ELEKT-D).
• ATMA CENA program tiers map to typical courses: Psycholytic Pathway $1,530 + $740/additional; Psychedelic Pathway $1,585 + $795/additional; Customized Programs $2,325–$6,930 for 2–8 sessions.

What the evidence supports for an acute course

The acute course is the structured initial run of ketamine sessions designed to produce response and (where possible) remission. Two distinct protocols dominate the literature.

IV ketamine acute course — CANMAT 2021 standard

CANMAT 2021 (Swainson et al., Canadian Journal of Psychiatry — PubMed) places IV racemic ketamine as a third-line treatment for adults with treatment-resistant depression and recommends 4 to 8 sessions over 2 to 3 weeks, typically at the standard 0.5 mg/kg over 40 minutes protocol. Singh et al. 2016 (Am J Psychiatry) directly compared twice-weekly versus thrice-weekly IV ketamine in TRD and found both schedules efficacious — twice-weekly with somewhat better tolerability. Most contemporary Canadian programs use twice-weekly.

Phillips et al. 2019 (Am J Psychiatry), a Canadian study from the Royal Ottawa, mapped single-dose response (~28%) versus six-dose response (~60%), supporting the value of a complete acute course rather than relying on a single dose for sustained benefit.

Spravato (esketamine) acute course — Health Canada label

The Spravato induction protocol established by the TRANSFORM trials (Popova 2019, Fedgchin 2019) and approved by Health Canada is:

• Weeks 1–4: twice-weekly dosing (56 mg or 84 mg per session) with concurrent oral SSRI/SNRI — 8 sessions
• Weeks 5–8: weekly dosing — 4 sessions
• Maintenance phase: weekly or every-other-week, individualized

Total induction phase: 12 sessions over 8 weeks. In real-world Canadian practice, observation requirements (≥2 hours per session under Janssen Journey) make Spravato more time-intensive per session than IV ketamine despite shorter active dosing.

For the modality-specific deep dives, see Intravenous Ketamine Therapy and Intranasal Ketamine and Spravato.

What the evidence supports for maintenance

The acute course produces response in 50–70% of patients at 24 hours; remission rates are typically 30–35%. Without maintenance dosing, response often wanes over 1–4 weeks. Two key data sets anchor maintenance frameworks.

SUSTAIN-1 (Daly et al. 2019, JAMA Psychiatry) — randomized maintenance-of-efficacy trial. Patients in stable remission on Spravato + oral antidepressant who continued treatment had significantly longer time to relapse than those switched to placebo + oral antidepressant. The data establishes that continued dosing extends remission rather than locking in a one-shot fix.

SUSTAIN-2 (Wajs et al. 2020, J Clin Psychiatry) — long-term open-label safety. 802 patients on Spravato + oral antidepressant for up to one year demonstrated acceptable long-term safety with no cases of interstitial cystitis. This is the largest published long-term dataset for any ketamine product and directly supports extended maintenance protocols.

For IV ketamine maintenance, Phillips 2019 used individualized scheduling in the maintenance phase. Real-world Canadian programs commonly transition from twice-weekly acute → weekly → every-other-week → monthly, tapering as durability allows.

ATMA CENA's program tiers — typical course mapping

ATMA CENA's published KAT pricing maps directly to the typical course structure. A non-refundable CAD $300 deposit applies.

What's bundled across the pathways: preparation sessions, dosing sessions, and integration sessions — ATMA CENA's three-phase KAP model. The price is for the full integrated course, not just the medicine.

For full pricing context including non-provider comparators, see Ketamine Therapy Cost in Canada.

What predicts needing more (or fewer) sessions?

Several variables associate with response trajectory in TRD ketamine treatment, though prediction at the individual level remains imperfect:

• Chronicity of TRD. Longer illness duration and more prior antidepressant failures often mean a more extended course, sometimes including extended acute series (8 sessions rather than 4–6) or earlier transition to maintenance.
• Comorbidity. Comorbid PTSD, anxiety, or chronic pain extends the symptomatic landscape; the acute course may produce response on the depression dimension while comorbid symptoms catch up over the integration period or require additional sessions.
• Anxious depression / melancholic features. Anxious-depression patients respond at similar or higher rates than non-anxious TRD in most analyses. Melancholic features have shown modestly favourable response patterns in some analyses, mixed in others.
• Concurrent benzodiazepines. May attenuate ketamine's antidepressant effect (Andrashko et al. 2020, Front Psychiatry). Our clinical team will discuss timing or tapering with you and your prescriber where appropriate.
• Family history of alcohol use disorder. Reproducibly associated with better ketamine response in multiple analyses — an unusual but consistent finding.
• BMI. Higher BMI has been associated with better response in some analyses.
• Suicidal ideation as primary symptom. Ketamine produces rapid SI reductions (Grunebaum 2018); patients in this profile may stabilize quickly with a shorter acute course but typically benefit from maintenance to prevent relapse.

The honest framing: the right course is calibrated to your indication, severity, comorbidity, and response trajectory — not a one-size answer.

When to stop, switch, or extend

Several decision points are standard in Canadian KAT practice:

No response after 4–6 acute infusions. Re-evaluate. The most common reasons: undiagnosed bipolarity (mood-history rescreen), inadequate prior antidepressant adequacy (pseudoresistance — see TRD deep dive), concurrent medication interactions, or genuine ketamine non-response. Options include: switch route or molecule (IV ↔ Spravato; IM ↔ SL), adjust dosing, add ECT comparison consideration (the ELEKT-D 2023 trial showed IV ketamine non-inferior to ECT for non-psychotic TRD), or pursue an alternative third-line strategy.

Partial response. Common — many patients see meaningful symptom reduction without full remission. Decision points: extend acute series (e.g., from 4 to 8 sessions); add or intensify integration psychotherapy; address comorbidity (anxiety, sleep, pain).

Sustained remission after acute course. A subset of patients sustain remission for weeks to months without further dosing. The clinical question becomes when (if at all) to re-dose at first sign of relapse. SUSTAIN-1 supports earlier re-dosing for relapse prevention.

Loss of response during maintenance. Common over months to a year. Options: re-induction (a new acute series), molecule or route switch, or transition off ketamine to alternative TRD strategy.

No further response and no remission across an extended trial. A small minority of TRD patients do not respond meaningfully to ketamine across an extended trial. Our clinical team will work with the referring psychiatrist on next-step options including ECT (ELEKT-D's comparator), additional pharmacologic strategies, or specialty referral.

How Spravato's course differs from IV in cost and time

The honest takeaway: IV ketamine acute courses are shorter and less time-intensive but typically out-of-pocket; Spravato is longer and time-heavier but is the form most likely to be insurance-covered. For full insurance navigation, see Insurance Coverage for Ketamine Therapy.

Frequently asked questions

What's the standard acute course? For IV ketamine in TRD, CANMAT 2021 recommends 4–8 sessions over 2–3 weeks, typically twice-weekly. For Spravato, the Health Canada-approved induction is twice-weekly for 4 weeks then weekly for weeks 5–8 — a total of 12 sessions over 8 weeks.

Do I need maintenance dosing? Often yes, but not always. SUSTAIN-1 demonstrated that continued Spravato dosing extends time to relapse vs. stopping; SUSTAIN-2 demonstrated up-to-1-year safety. Some patients sustain remission without further dosing; many benefit from individualized maintenance every 1–4 weeks tapering as durability allows.

How fast will I respond? At 24 hours after a single dose, acute response (≥50% depression score reduction) occurs in roughly 50–70% of patients. Across a 4–6 session acute course, response rates climb. Individual trajectories vary; some patients respond after the first session, others develop response across the series.

What if I don't respond after the first 4–6 sessions? Re-evaluate with the clinical team. Common reasons include undiagnosed bipolarity, pseudoresistance, medication interactions (benzodiazepines blunt effect), or genuine non-response. Options include switching route or molecule, extending the series, or considering ECT (ELEKT-D demonstrated comparable efficacy).

Will I need ketamine forever? Not necessarily. Long-term outcomes vary. Some patients use a single acute course and remain in remission with appropriate aftercare. Others maintain monthly or quarterly boosters. A subset benefit from ongoing maintenance dosing indefinitely. The honest framing: this is a treatment, not a cure, and durability planning is part of intake.

How does ATMA CENA's pricing map to a typical course? A 4-session course on the Psycholytic Pathway is approximately $3,750; on the Psychedelic Pathway, approximately $3,970. A 6-session course is $5,230 or $5,560 respectively. The Customized program ranges $2,325–$6,930 covering 2–8 sessions. Bundled pricing includes preparation, dosing, and integration sessions.

Is Spravato more sessions than IV? Yes — the Health Canada Spravato induction protocol is 12 sessions over 8 weeks versus 4–8 sessions over 2–3 weeks for IV. Spravato sessions also have mandatory ≥2-hour observation (vs ~30–60 minutes for IV), making total in-clinic time longer.

Can I do a shorter course if I respond fast? Possible but discussed clinically. Some patients with rapid robust response may transition earlier to maintenance; others benefit from completing the planned acute series for durability. Our clinical team revisits the plan at each session.

What if insurance only covers Spravato? Spravato is the form most likely to have private prior-auth coverage in Canada. If Spravato is the realistic financial pathway, the longer acute course (12 sessions) is offset by largely-covered cost. ATMA CENA can route Spravato-eligible patients via coordinated care when direct administration is not in-house.

Where can I find pricing for ketamine therapy in Canada more broadly? See Ketamine Therapy Cost in Canada for a full Canadian pricing breakdown.

Sources

1. ATMA CENA — Psychedelic-Assisted Therapy (pricing): https://psychedelic.healthcare/
2. Swainson J, et al. (2021). CANMAT racemic ketamine task force recommendations. Can J Psychiatry. https://pubmed.ncbi.nlm.nih.gov/33174760/
3. Singh JB, et al. (2016). Twice-weekly vs thrice-weekly IV ketamine in TRD. Am J Psychiatry. https://pubmed.ncbi.nlm.nih.gov/27056608/
4. Phillips JL, et al. (2019). Single, repeated, and maintenance IV ketamine for TRD. Am J Psychiatry. https://pubmed.ncbi.nlm.nih.gov/30764648/
5. Daly EJ, et al. (2019). SUSTAIN-1 — Spravato maintenance of efficacy. JAMA Psychiatry. https://pubmed.ncbi.nlm.nih.gov/31268507/
6. Wajs E, et al. (2020). SUSTAIN-2 — Spravato long-term safety. J Clin Psychiatry. https://pubmed.ncbi.nlm.nih.gov/32316080/
7. Anand A, et al. (2023). Ketamine versus ECT for nonpsychotic TRD: ELEKT-D. N Engl J Med. https://pubmed.ncbi.nlm.nih.gov/37224135/
8. Andrashko V, et al. (2020). Benzodiazepine attenuation of ketamine antidepressant effect. Front Psychiatry. https://pubmed.ncbi.nlm.nih.gov/33384625/
9. Health Canada DPD — Spravato: https://health-products.canada.ca/dpd-bdpp/info?lang=eng&code=98903

Related articles in this cluster

• Ketamine Therapy in Canada
• What Is Ketamine Therapy?
• Ketamine Therapy Cost in Canada
• How to Qualify for Ketamine Therapy in Canada
• Ketamine Therapy for Treatment-Resistant Depression (deep dive)
• Ketamine vs Antidepressants
• Ketamine vs Spravato
• Intravenous Ketamine Therapy
• Intranasal Ketamine and Spravato
• Insurance Coverage for Ketamine Therapy
• Find care near you

Last updated: 2026-05-06