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Psychedelic Therapy for Anxiety: What the Evidence Actually Shows

14 min read
A calm, softly lit therapy room with two empty chairs by a window, conveying a supported and unhurried setting for anxiety care.

Anxiety disorders affect roughly one in four Canadians at some point in life. This guide explains what psychedelic-assisted therapies actually show for anxiety, who has the strongest evidence behind them, and where honest gaps remain, including why the answer differs sharply depending on which type of anxiety you have.

Medically reviewed by Jacque Lovely, RN, MN, MBA, PMP, Reg #74334, 2026-05-27.

Key takeaways

  • The strongest published psilocybin evidence for anxiety is specifically in cancer-related anxiety and end-of-life distress (Griffiths 2016 [PMID 27909165]; Ross 2016 [PMID 27909164]), not generalized anxiety or panic disorder. For these patients, legal access requires Health Canada approval on a case-by-case basis, initiated by a physician.
  • Generalized anxiety disorder (GAD), panic disorder, social anxiety disorder, and OCD are off-pathway or research-stage for psychedelic-assisted therapy. No pivotal RCT exists for most of these.
  • Off-label ketamine has the most relevant evidence for primary anxiety disorders: Glue 2017 [PMID 28441895] for treatment-refractory GAD/SAD, and Rodriguez 2013 (PMID 23783065) for OCD. Effect sizes are smaller than for treatment-resistant depression, and these are proof-of-concept trials.
  • Spravato (esketamine) is NOT approved for anxiety disorders in Canada. Health Canada approved it for treatment-resistant depression only.
  • First-line treatments, including CBT, SSRIs, SNRIs, and exposure-based protocols (ERP for OCD), should typically come first. Psychedelic-assisted therapy is appropriate to consider after adequate first-line trials.
  • No psychedelic-assisted therapy is Health Canada-approved for anxiety disorders.
  • A named ATMA CENA clinician is available to discuss your specific situation. Book a free information call.

What is psychedelic-assisted therapy for anxiety?

Psychedelic-assisted therapy (PAT) combines a psychoactive substance with structured psychological support: preparation before, supervised dosing, and integration afterward. For anxiety, no single psychedelic-assisted treatment is Health Canada-approved. The evidence base is tiered by population and substance, and the honest picture requires distinguishing between cancer-related anxiety (where psilocybin evidence is strongest), primary anxiety disorders (where evidence is early or absent), and off-label ketamine (where small proof-of-concept data exist). You can read more about the general model on our psychedelic-assisted therapy page.

This article covers three tiers:

  1. Psilocybin for cancer-related anxiety, the most evidence
  2. Off-label ketamine for primary anxiety disorders, a small but real signal that remains research-stage
  3. Spravato and what it is NOT approved for, a critical clarification

The strongest published evidence for psilocybin and anxiety comes from two landmark 2016 trials in patients with life-threatening cancer.

Griffiths et al. 2016 (Johns Hopkins) enrolled 51 adults with life-threatening cancer and significant anxiety and depression. Participants received a single high-dose psilocybin session (22 or 30 mg/70 kg) with psychological support. At six-month follow-up, approximately 80% of participants showed clinically significant reductions in anxiety and depression [Griffiths 2016, J Psychopharmacol 30(12):1181-1197, PMID 27909165].

Ross et al. 2016 (NYU) ran a parallel trial in 29 cancer patients using a crossover design. Single-dose psilocybin (0.3 mg/kg) produced immediate, substantial, and sustained improvement in anxiety and depression compared to active placebo. Roughly 60 to 80% of participants maintained clinically significant reductions at 6.5-month follow-up [Ross 2016, J Psychopharmacol 30(12):1165-1180, PMID 27909164].

Both studies were published in the same December 2016 issue of Journal of Psychopharmacology. They remain the most rigorous published evidence for psilocybin as an anxiolytic. The anxiety in these studies was cancer-related existential distress, not generalized anxiety disorder or panic disorder. Long-term follow-up at 4.5 years (Agin-Liebes et al. 2020, J Psychopharmacol 34(2):155-166, PMID 31916890) showed sustained reductions in distress, with the majority of participants rating the psilocybin session as one of the most meaningful experiences of their lives.

What this means for Canadian access: For psilocybin, legal access in Canada requires Health Canada approval on a case-by-case basis, initiated by a physician, and approval is not guaranteed. Distress associated with a life-threatening illness, which can include cancer-related anxiety, is among the situations most often considered. For patients in this category, an information call can help clarify whether this pathway may apply. See also our page on end-of-life care.

Important context: The Griffiths and Ross 2016 trials enrolled patients whose anxiety was tied to a life-threatening cancer diagnosis. The findings do not straightforwardly generalize to people with primary anxiety disorders (GAD, panic, social anxiety) who do not have a life-threatening illness. Broader generalization is mechanistically plausible but not yet established by comparable clinical trials in non-cancer populations.

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Tier 2: Off-label ketamine for primary anxiety disorders

For people with GAD, social anxiety disorder (SAD), or OCD who have not responded to first-line treatments, off-label ketamine has a small but real evidence signal. This is research-stage evidence, not an approved indication.

GAD and social anxiety disorder

Glue et al. 2017 conducted a dose-escalation RCT in patients with treatment-refractory GAD and/or SAD. Single subcutaneous ketamine doses produced rapid, dose-related reductions in anxiety symptoms [Glue 2017, J Psychopharmacol 31(10):1302-1305, PMID 28441895]. The same research group subsequently published a three-month maintenance study (Glue et al. 2018) and a double-blind psychoactive-controlled replication (Glue et al. 2020) showing sustained anxiolytic effects with weekly ketamine.

A 2021 meta-analysis by Whittaker et al. [PMID 34925757] pooled six RCTs across anxiety-related conditions and found a pooled odds ratio of 28.94 for ketamine response in social anxiety disorder (95% CI: 3.45-242.57). That confidence interval is very wide, and the individual studies have small samples. The signal is real; the evidence base is early. These are proof-of-concept findings, not the depth of evidence that supports ketamine for treatment-resistant depression.

OCD

Rodriguez et al. 2013 ran a double-blind, placebo-controlled crossover trial of single-dose intravenous ketamine (0.5 mg/kg) in 15 adults with OCD with near-constant obsessions [PMID 23783065]. Ketamine produced rapid reduction in obsessive-compulsive symptoms; 50% maintained response at one week. This is a proof-of-concept trial, not a pivotal study. Effect sizes were smaller than ketamine's antidepressant effect in TRD.

Ketamine framing for anxiety in Canada: Ketamine is approved by Health Canada as an anaesthetic. Use for depression, anxiety, PTSD, and other mental-health indications is off-label, regulated by provincial medical regulators. Off-label ketamine for anxiety is generally not covered by provincial drug plans or most private insurers, so cost is typically out-of-pocket. For a breakdown of what ketamine therapy costs in Canada, see our ketamine therapy cost guide.

What Spravato (esketamine) is NOT approved for

Spravato (intranasal esketamine) received Health Canada approval in May 2020 for treatment-resistant major depressive disorder (TRD), specifically for adults who have not responded adequately to at least two adequate courses of antidepressants in the current episode.

Spravato is not approved in Canada for:

  • Generalized anxiety disorder
  • Panic disorder
  • Social anxiety disorder
  • OCD
  • Any anxiety disorder as a primary indication

A separate US FDA approval exists for esketamine in MDD with acute suicidal ideation or behaviour (MDSI). That indication does not exist in Canada; Health Canada has not approved Spravato for the MDSI indication. Canadian prescribers should not imply this approval is available.

Off-label prescribing of Spravato for anxiety may occur at a physician's discretion, but insurance coverage for anxiety indications is not established, and there is no pivotal RCT supporting Spravato specifically for anxiety disorders.

Wondering if this is right for you?

Our clinical team can walk you through your options — no referral needed to start.

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The honest picture: primary anxiety disorders remain off-pathway

Generalized anxiety disorders, panic disorder, and specific phobias are among the most common mental health conditions in Canada, affecting roughly one in four people at some point in life [Public Health Agency of Canada]. For most of these conditions, psychedelic-assisted therapy is not an established or approved treatment.

Anxiety type Psilocybin evidence Ketamine evidence Spravato evidence
Cancer-related / end-of-life anxiety Strongest: Griffiths 2016, Ross 2016 Not specifically studied Not approved
Generalized anxiety disorder No pivotal RCT in non-cancer population Glue 2017, proof-of-concept, small samples Not approved
Social anxiety disorder No dedicated RCT Glue 2017; Whittaker 2021 meta-analysis; early data Not approved
OCD Moreno 2006, 9-subject uncontrolled pilot only Rodriguez 2013, proof-of-concept, n=15 Not approved
Panic disorder Zero dedicated RCTs identified No dedicated trial Not approved

The evidence base for psilocybin in non-cancer primary anxiety disorders is limited. Goodwin 2022 (NEJM, PMID 36322843) found a broad signal in patients with TRD who also had comorbid anxiety symptoms, and Carhart-Harris 2021 (NEJM, PMID 33852780) showed anxiety as a secondary outcome in an MDD trial, but neither of these is an anxiety-disorder primary trial.

CBT, exposure-based protocols (ERP for OCD), SSRIs, and SNRIs remain the first-line standard of care for all primary anxiety disorders. Psychedelic-assisted therapy is appropriate to consider after adequate first-line trials have not produced sufficient response, and only within available regulatory and access frameworks.

Safety considerations specific to anxiety presentations

Anxiety about the psychedelic experience itself is one of the most consistent themes in screening for anxiety-disorder presentations. Several specific considerations apply:

  • Anticipatory anxiety: High baseline anxiety can heighten anticipatory distress before dosing. Substantial preparation is important for anxiety-disorder patients, meaning more sessions, not fewer.
  • Psychosis risk screening: Psilocybin activates 5-HT2A receptors and can precipitate or worsen psychotic symptoms. Personal history of schizophrenia, schizoaffective disorder, or any primary psychotic disorder, and first-degree family history of these conditions, is a standard exclusion from psilocybin trials.
  • Ketamine dissociation: Ketamine produces dissociative effects that some patients find distressing. For patients whose anxiety involves derealization or depersonalization, this requires careful screening.
  • Bipolar I: An active manic or mixed episode is a near-absolute contraindication for psilocybin and MDMA-assisted therapy. Ketamine for bipolar depression requires concurrent mood stabilizer coverage.

These are not reasons to avoid psychedelic-assisted therapy where appropriate. They are reasons why comprehensive intake, screening, and preparation are non-negotiable, particularly for anxiety presentations.

Wondering if this is right for you?

Our clinical team can walk you through your options — no referral needed to start.

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How ATMA CENA approaches anxiety

ATMA CENA's clinical team uses a three-phase model: preparation, medically supervised dosing, and integration. For anxiety presentations, this structure is particularly important. Key aspects of ATMA CENA's approach:

  • Honest intake: ATMA CENA will be direct about whether psychedelic-assisted therapy is an appropriate option for your specific anxiety presentation, or whether first-line evidence-based treatment is the appropriate next step.
  • CoCare model: If you already have an anxiety therapist, CBT therapist, or OCD specialist, our CoCare program can partner with your therapist if they have the appropriate training and build a service agreement with us.
  • Condition routing: Cancer-related anxiety and end-of-life distress follow a different intake pathway than primary anxiety disorders. You can learn more on our anxiety and end-of-life care pages.

If you are evaluating whether psychedelic-assisted therapy might fit your situation, book a free 15-minute information call to discuss your history with our clinical team.

Frequently asked questions

Is psychedelic therapy approved for anxiety in Canada?

No. No psychedelic-assisted therapy is Health Canada-approved for anxiety disorders. Spravato is approved for treatment-resistant depression only, not for anxiety. Off-label ketamine and psilocybin are not approved indications for primary anxiety disorders. For psilocybin, legal access requires Health Canada approval on a case-by-case basis, initiated by a physician, and it is most often considered for treatment-resistant major depressive disorder or distress associated with a life-threatening illness, which can include cancer-related anxiety as part of that distress.

What is the strongest psilocybin evidence for anxiety?

Griffiths et al. 2016 [PMID 27909165] and Ross et al. 2016 [PMID 27909164], both published in Journal of Psychopharmacology, December 2016. Both enrolled cancer patients with life-threatening diagnoses and significant anxiety and depression. Both found substantial, sustained reductions in anxiety at follow-up. These are the anchor studies, and both are specific to cancer-related anxiety, not generalized anxiety disorder.

Does psilocybin work for non-cancer anxiety?

The published psilocybin anxiety evidence is concentrated in cancer-related populations. For primary anxiety disorders (GAD, panic, social anxiety), there is no phase 3 RCT. Mechanistic arguments support plausibility, and some TRD and MDD trials show anxiety as a secondary outcome, but that evidence does not establish psilocybin as a treatment for GAD or panic disorder.

What does the ketamine evidence say for GAD?

Glue et al. 2017 [PMID 28441895] showed rapid, dose-related reductions in anxiety symptoms with single-dose subcutaneous ketamine in treatment-refractory GAD and SAD patients. A subsequent meta-analysis (Whittaker 2021, PMID 34925757) showed an OR of 28.94 for SAD response, with a very wide confidence interval (3.45-242.57) reflecting small sample sizes across studies. The signal is consistent; the evidence base is proof-of-concept, not pivotal.

What is the evidence for ketamine in OCD?

Rodriguez et al. 2013 (PMID 23783065), a double-blind crossover RCT in 15 OCD patients, found rapid reduction in obsessions with single intravenous ketamine. 50% maintained response at one week. Small sample, proof-of-concept only. Effect sizes were smaller than ketamine's antidepressant effect for TRD. There is no large RCT of ketamine for OCD.

Can I use Spravato for anxiety?

Spravato is not approved in Canada for anxiety disorders. It is approved for treatment-resistant MDD only. The US FDA has an additional approval for MDD with acute suicidal ideation; that indication does not exist in Canada. Off-label prescribing at physician discretion is possible but insurance coverage for anxiety indications is not established.

Should I try first-line treatments before psychedelic therapy?

Yes, in almost all cases. CBT (and ERP specifically for OCD), SSRIs, and SNRIs are the standard of care for anxiety disorders with the most evidence. Psychedelic-assisted therapy is typically appropriate to consider after adequate first-line trials. The exception is cancer-related anxiety, where the urgency of the clinical situation may make the pathway more direct.

Anxiety and depression in adults with life-threatening cancer is among the situations Health Canada most often considers when reviewing physician-initiated psilocybin requests. The process is case by case, and approval is not guaranteed. If you or someone you care for has cancer-related anxiety, an information call with ATMA CENA's clinical team can help clarify whether this pathway may be relevant. See also our page on end-of-life care.

What does the preparation phase look like for someone with high anxiety?

For patients with significant baseline anxiety, ATMA CENA recommends more preparation sessions, not fewer. The preparation phase addresses anticipatory anxiety directly, builds trust with the clinical team, and establishes set and setting that reduces the risk of a distressing experience. This is not a generic add-on. For anxiety-disorder patients, it is the structural foundation that makes dosing safe and productive.

Compliance disclaimer

Psilocybin and MDMA are restricted drugs under Canada's Controlled Drugs and Substances Act. Legal patient access to psilocybin- or MDMA-assisted therapy requires Health Canada approval on a case-by-case basis, initiated by a physician, and approval is not guaranteed. Access is most often considered for adults with treatment-resistant major depressive disorder or distress associated with a life-threatening illness.

Ketamine is approved by Health Canada as an anaesthetic. Use for depression, anxiety, PTSD, and other mental-health indications is off-label, regulated by provincial medical regulators.

Spravato (esketamine) is Health Canada-approved for treatment-resistant MDD only. It is not approved for anxiety disorders in Canada.

Nothing in this article constitutes a clinical recommendation for a specific individual. All clinical decisions require assessment by a qualified prescribing physician.

About the author

Reverdi Darda, RN, BScN, Reg #61707 | CEO & Founder, ATMA CENA

Reverdi Darda, RN is CEO & Founder of ATMA CENA and a Registered Nurse with over three decades of experience in healthcare operations, community engagement, policy development, and strategic planning. A recognized leader in mental health access, Reverdi has dedicated her career to advancing evidence-based treatment models and advocating for policy change that prioritizes effective care. She founded ATMA CENA to expand practitioner and public access to psychedelic-assisted therapy across Canada.

Sources

  1. Griffiths RR, Johnson MW, Carducci MA, et al. (2016). Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: A randomized double-blind trial. J Psychopharmacol, 30(12):1181-1197. PMID: 27909165. https://pubmed.ncbi.nlm.nih.gov/27909165/
  2. Ross S, Bossis A, Guss J, et al. (2016). Rapid and sustained symptom reduction following psilocybin treatment for anxiety and depression in patients with life-threatening cancer: a randomized controlled trial. J Psychopharmacol, 30(12):1165-1180. PMID: 27909164. https://pubmed.ncbi.nlm.nih.gov/27909164/
  3. Agin-Liebes GI, Malone T, Yalch MM, et al. (2020). Long-term follow-up of psilocybin-assisted psychotherapy for psychiatric and existential distress in patients with life-threatening cancer. J Psychopharmacol, 34(2):155-166. PMID: 31916890. https://pubmed.ncbi.nlm.nih.gov/31916890/
  4. Glue P, Medlicott NJ, Harland S, et al. (2017). Ketamine's dose-related effects on anxiety symptoms in patients with treatment refractory anxiety disorders. J Psychopharmacol, 31(10):1302-1305. PMID: 28441895. https://pubmed.ncbi.nlm.nih.gov/28441895/
  5. Whittaker E, Dadabayev AR, Joshi SA, Glue P. (2021). Systematic review and meta-analysis of randomized controlled trials of ketamine in the treatment of refractory anxiety spectrum disorders. Ther Adv Psychopharmacol, 11:20451253211056743. PMID: 34925757. https://pubmed.ncbi.nlm.nih.gov/34925757/
  6. Rodriguez CI, Kegeles LS, Levinson A, et al. (2013). Randomized controlled crossover trial of ketamine in obsessive-compulsive disorder: proof-of-concept. Neuropsychopharmacology, 38(12):2475-83. PMID: 23783065. https://pubmed.ncbi.nlm.nih.gov/23783065/
  7. Goodwin GM, Aaronson ST, Alvarez O, et al. (2022). Single-Dose Psilocybin for a Treatment-Resistant Episode of Major Depression. New England Journal of Medicine, 387(18):1637-1648. PMID: 36322843. https://pubmed.ncbi.nlm.nih.gov/36322843/
  8. Carhart-Harris R, Giribaldi B, Watts R, et al. (2021). Trial of Psilocybin versus Escitalopram for Depression. New England Journal of Medicine, 384(15):1402-1411. PMID: 33852780. https://pubmed.ncbi.nlm.nih.gov/33852780/
  9. Health Canada, requests to access psychedelic-assisted psychotherapy through Health Canada's case-by-case review. https://www.canada.ca/en/health-canada/services/drugs-health-products/drug-products/announcements/requests-special-access-program-psychedelic-assisted-psychotherapy.html

Last updated: 2026-05-27. Article reviewed every 6 months.

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