Obsessive-compulsive disorder (OCD) affects approximately 1–3% of Canadians across the lifespan and is now classified in DSM-5 within its own chapter — Obsessive-Compulsive and Related Disorders — distinct from the anxiety disorders. The Anxiety Disorders and Psychedelic-Assisted Therapy hub touches on OCD as a related concern; this article is a focused OCD deep-dive for patients, families, and clinicians evaluating psychedelic-assisted therapy in the Canadian context. We cover DSM-5 criteria, the OCD-related disorders (BDD, hoarding, trichotillomania, excoriation, substance/medication-induced OCD), the foundational evidence base — Exposure and Response Prevention (ERP) plus higher-dose SSRIs — and the more limited investigational evidence for psilocybin (Moreno 2006) and ketamine (Rodriguez 2013) in OCD, including Yale University's ongoing psilocybin OCD program and Compass Pathways' psilocybin OCD work.

Key takeaways

DSM-5 reclassified OCD into its own chapter — Obsessive-Compulsive and Related Disorders — separate from anxiety disorders, alongside body dysmorphic disorder (BDD), hoarding disorder, trichotillomania, excoriation (skin-picking) disorder, and substance/medication-induced OCD.

First-line evidence-based care is foundational: Exposure and Response Prevention (ERP) psychotherapy, with SSRIs at higher doses than for depression (sertraline, fluvoxamine, paroxetine, fluoxetine) and clomipramine as the most established second-line.

Treatment-resistant OCD (TRO): augmentation strategies include atypical antipsychotics (aripiprazole, risperidone) and, for severe refractory cases, deep brain stimulation (DBS).

Psilocybin in OCD — investigational. The first modern published trial is Moreno et al. 2006 (PMID 17196053), a small open-label safety/tolerability study. Yale University runs an ongoing psilocybin OCD program; Compass Pathways has a psilocybin OCD program in development.

Ketamine in OCD — investigational. Rodriguez et al. 2013 (PMID 23631729) RCT showed rapid reduction in obsessive-compulsive symptoms with single-dose IV ketamine; effect sizes smaller and durability shorter than ketamine TRD evidence.

No psychedelic-assisted therapy is Health Canada-approved for OCD — Spravato is approved for TRD only.

TRO with comorbid TRD: psychedelic-assisted therapy is more clearly indicated when treatment-resistant depression is also present.

Pediatric OCD: family-based therapy (FBT analog) and CBT-ERP are first-line; adolescents are not enrolled in psychedelic OCD RCTs.

Defining OCD and OCD-related disorders

DSM-5 moved OCD out of the anxiety chapter into a new Obsessive-Compulsive and Related Disorders chapter, recognizing shared phenomenology, family history, and neurobiology across these conditions.

DSM-5 OCD criteria

Obsessions: recurrent and persistent thoughts, urges, or images that are experienced as intrusive and unwanted; the individual attempts to ignore, suppress, or neutralize them with another thought or action (i.e., a compulsion).
Compulsions: repetitive behaviours (e.g., handwashing, ordering, checking) or mental acts (e.g., praying, counting, repeating words silently) that the individual feels driven to perform in response to an obsession or according to rigid rules.
Time-consuming: obsessions or compulsions take more than 1 hour per day, or
Distress / impairment: cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.
Not attributable to physiological effects of a substance or another medical condition; not better explained by another mental disorder.

OCD is further specified by insight (good/fair, poor, absent/delusional) and presence of a tic-related subtype.

OCD-related disorders (DSM-5 chapter)

Body dysmorphic disorder (BDD): preoccupation with one or more perceived defects or flaws in physical appearance not observable or appearing slight to others; repetitive behaviours (mirror checking, grooming) or mental acts in response.
Hoarding disorder: persistent difficulty discarding possessions regardless of value, leading to accumulation that congests living areas.
Trichotillomania (hair-pulling disorder): recurrent hair pulling resulting in hair loss.
Excoriation (skin-picking) disorder: recurrent skin picking resulting in skin lesions.
Substance/medication-induced obsessive-compulsive and related disorder: obsessions, compulsions, or related symptoms attributable to a substance or medication.
OCD due to another medical condition and other specified / unspecified OCRD.

For broader anxiety context: Anxiety Disorders and Psychedelic-Assisted Therapy.

Foundational evidence-based treatment

OCD has a robust first-line evidence base that must anchor any conversation about investigational psychedelic-assisted therapy.

Exposure and Response Prevention (ERP)

ERP is the foundational psychotherapy for OCD. It is a structured cognitive-behavioural protocol in which the patient is systematically exposed to obsession-triggering stimuli while preventing the compulsive response. International OCD Foundation (IOCDF) and Canadian Network for Mood and Anxiety Treatments (CANMAT) guidelines list ERP as first-line. Effect sizes are large, durable, and consistent across multiple decades of trials.

SSRIs at higher doses

OCD typically requires higher SSRI doses than depression, with response often emerging at 8–12 weeks rather than 4–6:

Sertraline — commonly 200 mg daily, sometimes higher
Fluvoxamine — 200–300 mg daily
Paroxetine — 40–60 mg daily
Fluoxetine — 60–80 mg daily
Escitalopram — 20–40 mg daily (off-label for higher doses)

Clomipramine (a tricyclic with strong serotonergic activity) is among the most efficacious medications in OCD trials but is generally placed second-line because of cardiac, anticholinergic, and seizure-risk side effect burden.

Treatment-resistant OCD (TRO)

When patients fail to respond adequately to two or more SSRI trials at adequate dose and duration and to ERP, augmentation strategies include:

Atypical antipsychotic augmentation: aripiprazole and risperidone have the most consistent RCT support. Quetiapine and olanzapine are sometimes used.
Glutamatergic agents: memantine, riluzole, N-acetylcysteine — emerging evidence base.
Intensive ERP (residential or intensive outpatient).
Repetitive transcranial magnetic stimulation (rTMS) — Health Canada-approved devices for OCD with specific protocols.
Deep brain stimulation (DBS) — for severe, refractory cases meeting strict criteria; Canadian centres in select academic neurosurgical programs.

This foundational landscape is what investigational psychedelic-assisted therapy is layered onto — not a replacement for.

The OCD evidence map for psychedelic-assisted therapy

Psilocybin and OCD

Moreno FA, Wiegand CB, Taitano EK, Delgado PL. (2006). Safety, tolerability, and efficacy of psilocybin in 9 patients with obsessive-compulsive disorder. Journal of Clinical Psychiatry, 67(11):1735-1740. PMID 17196053. The first published modern psychedelic OCD trial — a small open-label study of nine OCD patients receiving four doses of psilocybin (very low to high) in a controlled setting. Found acute reductions in obsessive-compulsive symptoms and good tolerability; not a controlled efficacy trial.
Yale University ongoing psilocybin OCD trials: a sustained academic program led by clinical investigators in the Yale OCD Research Clinic studying psilocybin in OCD with controlled designs; results contributing to the modern evidence base. Patients should consult ClinicalTrials.gov for current enrolment status.
Compass Pathways psilocybin OCD program: Compass has signalled an OCD development program building on its psilocybin TRD MAGNUS phase 3 work. Status and timelines should be verified against current Compass disclosures.
Mechanistic rationale: 5-HT2A receptor agonism and proposed effects on cognitive flexibility, default-mode network reset, and obsessional rumination underlie ongoing investigation.

Ketamine and OCD

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 23631729. Single-dose IV ketamine (0.5 mg/kg) versus saline in OCD patients; rapid reduction in obsessive-compulsive symptoms in the ketamine arm. Proof-of-concept; durability beyond ~1 week limited.
Bloch MH and colleagues — Yale group ketamine and OCD work, including open-label and adjunctive studies exploring NMDA modulation in OCD.
Adams TG, et al. (2017) — ketamine effects on OCD-related neurocircuitry and symptom domains.
Effect sizes smaller than TRD ketamine evidence and durability shorter; sustained response after a single dose is uncommon, and structured maintenance protocols for OCD are not standardized.

Spravato — NOT for OCD

Spravato (esketamine) is Health Canada-approved for treatment-resistant depression only — not for OCD or any OCD-related disorder. Off-label use is at clinical discretion within Canadian prescribing principles but is rarely the appropriate first investigational choice in pure OCD.

MDMA — NOT for OCD

MDMA-assisted therapy is investigational for PTSD only — not for OCD. Patients should be cautious of providers conflating these. See MDMA-Assisted Therapy in Canada.

For more detail see Psilocybin for Anxiety and Depression and Ketamine Therapy in Canada.

Decision framework — comparing OCD options

Factor	ERP + SSRI (first-line)	Augmentation (TRO)	Off-label ketamine	Psilocybin (SAP)
Health Canada approval (OCD)	Yes (SSRIs labelled for OCD)	Yes for some; off-label for others	No (off-label; med approved as anaesthetic)	No (SAP investigational)
Strongest OCD-specific evidence	Multi-decade RCT base	Aripiprazole/risperidone augmentation RCTs	Rodriguez 2013 RCT	Moreno 2006 open-label; Yale ongoing
Effect size	Large, durable	Moderate	Moderate, short durability	Preliminary
Sessions to evaluate	Weeks to months	Weeks to months	1–6 sessions	1–2 dosing sessions
Insurance coverage	Provincial drug plans (SSRI) + private therapy	Variable	Generally no	No
Psychotherapy	ERP is the modality	ERP continues	Variable	Always required (preparation + integration)

Treatment-resistant OCD with comorbid TRD

A clinically important subgroup: patients with TRO who also meet TRD criteria. Here the case for psychedelic-assisted therapy is more clearly indicated, because:

Spravato (esketamine) has Health Canada approval for the TRD component
Off-label ketamine has substantial RCT evidence in TRD (Anand 2023 ELEKT-D non-inferior to ECT)
Psilocybin under SAP has the Goodwin 2022 NEJM COMP001 phase 2 evidence in TRD

In these cases the depression component drives the approval/SAP rationale; OCD-specific symptom change is monitored as a secondary outcome. Patients and clinicians should not assume OCD remission will follow depression remission — these are distinct symptom domains. See Treatment-Resistant Depression and Psychedelic-Assisted Therapy.

OCD-related disorders — specific considerations

Body dysmorphic disorder (BDD)

BDD shares phenomenology with OCD (intrusive thoughts, repetitive behaviours, partial insight) but has distinct features: appearance-focused obsessions, mirror checking, reassurance-seeking, sometimes severe avoidance. CBT with BDD-specific modifications and SSRIs (often at OCD-equivalent higher doses) are first-line. Insight is often poorer in BDD than in OCD, which has implications for psychedelic-assisted therapy preparation: comprehensive screening for delusional-spectrum presentations is essential before considering serotonergic psychedelics. Published psychedelic BDD evidence is minimal.

Hoarding disorder

Hoarding disorder responds less well to standard SSRI/ERP than core OCD. CBT specifically adapted for hoarding (Steketee/Frost protocols) is the leading psychotherapy. SSRI evidence is more limited than for OCD. Psychedelic-assisted therapy evidence in hoarding is negligible at this writing — patients should not expect the OCD evidence base to translate.

Trichotillomania and excoriation

These body-focused repetitive behaviours have a different treatment profile: habit reversal training (HRT) is the leading psychotherapy; N-acetylcysteine has small-RCT support; SSRI evidence is mixed. Psychedelic-assisted therapy evidence is essentially absent for these conditions.

Substance/medication-induced OCD

Onset linked to a specific substance or medication. Treatment focuses on the offending agent and standard OCD care. Psychedelic-assisted therapy is rarely appropriate as a first investigational step.

Pediatric OCD

OCD frequently begins in childhood or adolescence. Pediatric OCD has a strong evidence base for CBT-ERP delivered with family involvement — analogous to family-based therapy (FBT) approaches in other pediatric conditions — and for SSRI use at age-appropriate doses. Adolescents have not been enrolled in published psychedelic OCD RCTs, and psychedelic-assisted therapy is not appropriate for pediatric OCD under current evidence and Canadian regulatory frameworks. Families seeking pediatric OCD care should pursue specialist CBT-ERP and child-and-adolescent psychiatry pathways.

Canadian access pathways for OCD

Civilian OCD pathway

CBT-ERP: provincial mental health programs (variable wait times); private OCD-specialty therapists; the IOCDF maintains a Canadian provider directory
SSRIs / clomipramine: provincial drug plans cover most SSRIs; clomipramine generally covered
Augmentation (atypical antipsychotics, rTMS): covered through standard pathways
Off-label ketamine for TRO: out-of-pocket dominantly; ~$400–$1,500/session
Psilocybin SAP: case-by-case Health Canada approval; capacity is smaller for OCD-primary indications than for TRD or end-of-life distress

Veterans (VAC)

Service-related OCD pathway depends on documentation
Ketamine therapy: case-by-case for service-related OCD with comorbid TRD or PTSD
Psilocybin: not covered

Workers' compensation

OCD may be compensable in specific workplace-exposure contexts (e.g., contamination OCD following occupational exposure)
Provincial WCB / WSIB pathways are case-by-case

For more on the access pathways covered above, see Ketamine Therapy in Canada and Psilocybin Therapy in Canada.

What the evidence does NOT say

No psychedelic-assisted therapy is approved for OCD in Canada.
The Moreno 2006 psilocybin OCD trial is small and uncontrolled. It is a foundational signal, not pivotal evidence.
Rodriguez 2013 ketamine OCD effects are short-lived. Single-dose IV ketamine produces rapid but transient reductions in obsessive-compulsive symptoms; durability and maintenance protocols for OCD remain unestablished.
Effect sizes in OCD are smaller than in TRD for ketamine, and the psilocybin OCD evidence is preliminary compared with TRD or end-of-life distress.
First-line ERP and adequate SSRI trials should typically come first. Psychedelic-assisted therapy is appropriately considered after high-fidelity ERP and adequate-dose SSRI trials have not produced sufficient response — and even then the strongest case is in patients with comorbid TRD.
Severe, refractory OCD has established neuromodulation pathways (rTMS, DBS) that should not be skipped over in favour of investigational psychedelic-assisted therapy.

How ATMA CENA works with OCD patients

Comprehensive intake: OCD history (Y-BOCS or equivalent severity measure), prior treatments (ERP fidelity, SSRI doses and durations, augmentation), comorbid conditions including TRD, screening for psychotic-disorder personal/family history, BDD/hoarding insight assessment
Three-phase model: preparation + dosing + integration — preparation is particularly important in OCD given anticipatory anxiety and intrusive-thought content
Coordinated care: OCD-specialty ERP therapist remains primary; ATMA CENA layers on top rather than replacing
Honest framing: ATMA CENA will route patients to first-line ERP and adequate SSRI trials before psychedelic-assisted therapy where clinically appropriate, and will be explicit when the evidence base for an OCD-related disorder (BDD, hoarding, trichotillomania, excoriation) is too thin to support investigational use.

For related treatment detail see Ketamine Therapy in Canada and Psilocybin Therapy in Canada.

Frequently asked questions

Is OCD an anxiety disorder? Not in DSM-5. OCD was reclassified into its own chapter — Obsessive-Compulsive and Related Disorders — alongside body dysmorphic disorder, hoarding disorder, trichotillomania, and excoriation. The phenomenology overlaps with anxiety but the disorder family is now distinct.

What's the first-line treatment for OCD? Exposure and Response Prevention (ERP) psychotherapy and SSRIs at higher doses than for depression (sertraline, fluvoxamine, paroxetine, fluoxetine). Clomipramine is the most established second-line medication. CANMAT and IOCDF guidelines anchor this care.

Are any psychedelic-assisted therapies approved for OCD in Canada? No. Spravato is approved for treatment-resistant depression only — not OCD. Off-label ketamine and psilocybin under the Special Access Program are investigational for OCD.

What's the strongest psilocybin OCD evidence? Moreno et al. 2006 (PMID 17196053) is the first published modern psilocybin OCD trial — a small open-label study of nine patients showing safety, tolerability, and acute symptom reduction. Yale University runs an ongoing psilocybin OCD program, and Compass Pathways has a psilocybin OCD program in development.

What about ketamine for OCD? Rodriguez 2013 (PMID 23631729) RCT showed rapid reduction in obsessive-compulsive symptoms with single-dose IV ketamine. Effect sizes are smaller than for TRD, and sustained-effect data are limited. Off-label use exists for treatment-resistant OCD, especially with comorbid TRD.

What if I have both OCD and TRD? Treatment-resistant OCD with comorbid treatment-resistant depression is the OCD subgroup where psychedelic-assisted therapy is most clearly indicated. The depression component drives the Spravato approval / SAP psilocybin rationale, with OCD symptoms monitored as a secondary outcome.

Is BDD treated the same as OCD? Mostly similar — CBT (with BDD-specific modifications) and SSRIs at OCD-equivalent doses are first-line. Insight is often poorer in BDD, which has implications for psychedelic-assisted therapy screening. Published psychedelic BDD evidence is minimal.

What about hoarding disorder? Hoarding disorder responds less well to standard SSRI/ERP; CBT specifically adapted for hoarding is the leading psychotherapy. Psychedelic-assisted therapy evidence in hoarding is negligible at present.

What about pediatric OCD? Children and adolescents are not enrolled in published psychedelic OCD RCTs. CBT-ERP with family involvement and age-appropriate SSRI dosing are first-line. Psychedelic-assisted therapy is not appropriate for pediatric OCD under current evidence.

Should I try ERP first? Generally yes. High-fidelity ERP from a trained OCD specialist plus an adequate SSRI trial at OCD-appropriate doses for 8–12 weeks anchors the first-line case. If response remains inadequate, augmentation (aripiprazole, risperidone), rTMS, intensive ERP, and — for severe refractory cases — DBS, sit ahead of investigational psychedelic-assisted therapy in the standard pathway.

What's the cost of psychedelic-assisted therapy for OCD?

Off-label IV ketamine: ~$500–$1,500/session
Off-label IM/SL ketamine: ~$400–$900/session
Psilocybin SAP: variable; supply via Filament Health no-charge SAP option exists; clinical hours separate
Insurance coverage for these uses is generally not available for OCD.

Sources

Moreno FA, Wiegand CB, Taitano EK, Delgado PL. (2006). Safety, tolerability, and efficacy of psilocybin in 9 patients with obsessive-compulsive disorder. Journal of Clinical Psychiatry, 67(11):1735-1740. PMID: 17196053.
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: 23631729.
Bloch MH, Wasylink S, Landeros-Weisenberger A, et al. (2012). Effects of ketamine in treatment-refractory obsessive-compulsive disorder. Biological Psychiatry, 72(11):964-70.
Adams TG, Bloch MH, Pittenger C. (2017). Intranasal ketamine and cognitive-behavioral therapy for treatment-refractory obsessive-compulsive disorder. Journal of Clinical Psychopharmacology, 37(2):269-271.
Pittenger C, Bloch MH. (2014). Pharmacological treatment of obsessive-compulsive disorder. Psychiatric Clinics of North America, 37(3):375-91.
American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders, 5th ed. (DSM-5) — Obsessive-Compulsive and Related Disorders chapter.
Katzman MA, Bleau P, Blier P, et al. (2014). Canadian clinical practice guidelines for the management of anxiety, posttraumatic stress and obsessive-compulsive disorders (CANMAT). BMC Psychiatry, 14 Suppl 1:S1. PMID: 25081580.
International OCD Foundation — Treatment guidelines: https://iocdf.org/about-ocd/treatment/
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.
Anand A, Mathew SJ, Sanacora G, et al. (2023). Ketamine versus ECT for Nonpsychotic Treatment-Resistant Major Depression. New England Journal of Medicine, 388(25):2315-2325. PMID: 37224135.
Health Canada — Special Access Program: https://www.canada.ca/en/health-canada/services/drugs-health-products/special-access.html
Health Canada — SAP psychedelic-assisted psychotherapy announcement: https://www.canada.ca/en/health-canada/services/drugs-health-products/drug-products/announcements/requests-special-access-program-psychedelic-assisted-psychotherapy.html
Compass Pathways — clinical program disclosures: https://compasspathways.com/our-research/comp360-clinical-program/
Yale OCD Research Clinic — psilocybin OCD program: https://clinicaltrials.gov (search "psilocybin OCD Yale" for current enrolment status).

Last updated: 2026-05-06

OCD and Psychedelic-Assisted Therapy — A Deep Dive