CANMAT and ICOCS launch 2025 international guideline for Obsessive-Compulsive Disorder

Headline change

The guideline formalizes a tiered approach to treatment-resistant OCD, establishing first-line augmentation agents like risperidone and aripiprazole, and second-line options including lamotrigine and memantine.

Bedside action

Routinely screen all patients with OCD for suicidality and use a validated scale like the Y-BOCS to establish a baseline and monitor treatment response.

The Canadian Network for Mood and Anxiety Treatments (CANMAT) and the International College of Obsessive-Compulsive Spectrum Disorders (ICOCS) have released their first-ever joint international guideline for the management of obsessive-compulsive disorder. This comprehensive document synthesizes current evidence for psychological, pharmacological, and neuromodulation therapies across the lifespan, providing clinicians with a structured, decision-oriented framework for a condition marked by high rates of treatment resistance and comorbidity.

Practice Notes

Key considerations for implementing the 2025 CANMAT/ICOCS recommendations in daily practice.

Do not miss

Actively screen all patients with OCD for suicidality.

Recent meta-analyses confirm a significantly elevated risk of both suicidal ideation and lifetime suicide attempts in this population. This dispels older notions that OCD was not associated with high suicide risk.

Stop doing this

Avoid premature discontinuation or switching of first-line therapies.

Both CBT with ERP and SRIs require an adequate trial of at least 12 weeks to show a clear signal of efficacy. Early adverse effects often precede clinical improvement, so patient reassurance is critical.

Special population

Stabilize mood before targeting OC symptoms in patients with comorbid Bipolar I Disorder.

The primary goal is mood stabilization with mood stabilizers or atypical antipsychotics. Augmenting with an SSRI for OCD can then be considered, but requires careful monitoring for a (hypo)manic switch.

Caution

Use caution when prescribing lamotrigine for treatment-resistant OCD.

While a second-line augmentation option, lamotrigine requires gradual titration due to the risk of severe side effects, including Stevens-Johnson Syndrome.

Key Recommendations

This guideline provides a comprehensive, tiered set of recommendations for the management of OCD. The guidance covers initial treatment selection between psychotherapy and pharmacotherapy, dosing and duration, management of common and complex comorbidities, and a structured, evidence-based approach to treatment-resistant OCD, offering clinicians a clear pathway for managing this often-chronic condition.

Key recommendations14 highlighted

In all patients with OCD at initial assessment and follow-up, actively screen for suicidality.

Line / Strengthessential

EvidenceEvidence is based on recent meta-analyses showing a pooled odds ratio of 0.135 for lifetime suicide attempts and 0.473 for lifetime suicidal ideation in patients with OCD. Risk factors include higher severity of obsessions and comorbid substance use or depressive disorders.

For practiceIntegrate routine suicide risk assessment into every OCD patient evaluation.

CaveatSpecific treatments for suicidality in OCD have not been examined, but standard suicide prevention approaches should be implemented.

p. 8 · Suicide risk

In all patients with OCD throughout treatment, routinely monitor clinical outcomes using an objective, validated scale such as the clinician-rated Y-BOCS or self-rated OCI-R.

Line / StrengthWe recommend

EvidenceThe Y-BOCS is considered the gold-standard for its sensitivity to change and validation in numerous clinical trials. Routine use allows for objective tracking of progress and informs decisions about treatment adequacy and adjustments.

For practiceUse a validated scale at baseline and follow-up to quantify treatment response.

p. 12 · Principles of Management

In initial treatment for most adults with OCD, offer Cognitive Behavioral Therapy (CBT) in the form of Exposure and Response Prevention (ERP) or Cognitive Therapy (CT).

Line / Strengthfirst-line

Level of EvidenceLevel 1

EvidenceEfficacy is supported by numerous RCTs and meta-analyses demonstrating superiority over comparison treatments. Both ERP and CT are effective when delivered individually (in-person or remotely), and ERP is also effective in a group format.

For practiceCBT/ERP is a primary, non-pharmacologic first-line treatment for OCD.

CaveatIn-person CBT is recommended over internet-delivered CBT for patients with higher baseline OCD symptom severity.

p. 28 · Psychotherapy

In initial pharmacotherapy for adults with OCD, prescribe an SSRI (sertraline, fluoxetine, fluvoxamine, citalopram, escitalopram, or paroxetine).

Line / Strengthfirst line

Level of EvidenceLevel 1

EvidenceEfficacy is established by multiple double-blind, placebo-controlled trials for each agent. Meta-analyses show no significant difference in efficacy between the different SSRIs, so selection should be based on patient profile, side effects, and comorbidities.

For practiceSSRIs are the first-choice medication class for OCD.

CaveatClomipramine is considered second-line due to its less favorable tolerability profile compared to SSRIs.

p. 15 · First-line Pharmacotherapy

In starting a patient on an SSRI for OCD, conduct at least a 12-week trial, titrating the dose to the maximum authorized and tolerated dosage.

Line / StrengthWe recommend

Level of EvidenceLevel 4

EvidenceControlled trials and a meta-analysis show that symptom improvement can continue for up to 12 weeks after treatment initiation. A dose-response relationship has been found, supporting titration to maximum tolerated doses to evaluate full effect.

For practiceDo not abandon an SSRI trial prematurely; ensure adequate dose and duration.

CaveatIf response is partial at 12 weeks, an extended trial may be considered before switching or augmenting.

p. 12 · Principles of Management

In patients who have responded to an SRI, continue treatment for at least 12 months, and possibly indefinitely, to prevent relapse.

Line / StrengthWe recommend

Level of EvidenceLevel 4

EvidenceRelapse is common upon SRI discontinuation. Relapse prevention studies for sertraline, paroxetine, escitalopram, fluoxetine, and clomipramine show superiority over placebo for maintaining response. Long-term treatment is advised given the chronic nature of OCD.

For practiceCounsel patients on the high risk of relapse and the need for long-term maintenance therapy.

CaveatIf discontinuation is necessary, withdrawal should be gradual with close monitoring for relapse and suicide risk.

p. 12 · Principles of Management

In patients with OCD who have not responded to a first-line SSRI, consider a trial of clomipramine (100-250 mg/day).

Line / Strengthsecond line

Level of EvidenceLevel 1

EvidenceClomipramine has consistently shown efficacy in seven DBPC trials and meta-analyses. While some head-to-head trials suggest marginal superiority over SSRIs, this is not statistically significant when excluding older trials.

For practiceClomipramine is a potent but second-line option for OCD due to side effects.

CaveatClomipramine is designated second-line due to its tolerability profile (anticholinergic effects, cardiac risks, seizures) being worse than SSRIs.

p. 15 · First-line Pharmacotherapy

In patients with treatment-resistant OCD (failed ≥1-2 adequate SRI trials), augment the current SRI with risperidone, aripiprazole, or haloperidol.

Line / Strengthfirst-line treatment

Level of EvidenceLevel 2

EvidenceMultiple meta-analyses support the efficacy of antipsychotic augmentation. A large network meta-analysis found these agents as a class were significantly superior to placebo. Risperidone and aripiprazole have the strongest evidence base from multiple RCTs.

For practiceAtypical antipsychotics are the first-line augmentation strategy for treatment-resistant OCD.

CaveatMonitor for metabolic side effects (weight gain) with SGAs. Augmentation trials should last at least 8 weeks.

p. 31 · Treatment Resistant OCD - Dopaminergic Agents

In patients with treatment-resistant OCD who failed or cannot tolerate first-line augmentation, consider augmentation with lamotrigine or memantine.

Line / Strengthsecond line treatment

Level of EvidenceLevel 2

EvidenceEvidence for these glutamatergic agents is based on a small number of positive DBPC trials. A meta-analysis supports lamotrigine efficacy, and two RCTs support memantine. These agents are considered effective alternatives to antipsychotic augmentation.

For practiceGlutamatergic agents are a second-line augmentation option for treatment-resistant OCD.

CaveatLamotrigine requires slow, gradual titration due to risk of severe rash (Stevens-Johnson Syndrome).

p. 32 · Treatment Resistant OCD - Glutamatergic Agents / NMDA receptor Antagonists

In patients with OCD and comorbid Bipolar I Disorder, first, stabilize mood with mood stabilizers and/or atypical antipsychotics. For persistent OC symptoms, augment with CBT (ERP), TMS, or an SSRI.

Level of EvidenceLevel 4

EvidenceThis recommendation is based on expert opinion and case series, prioritizing the management of bipolar disorder to prevent mood destabilization. There are no controlled trials for this specific comorbid population.

For practiceIn OCD with Bipolar I, treat the mood disorder first, then cautiously address OCD.

CaveatIf augmenting with an SSRI, patients must be carefully monitored for a (hypo)manic switch.

p. 16 · Comorbidity Treatment

In patients with OCD and comorbid schizophrenia, augment existing antipsychotic treatment with an SRI and/or aripiprazole, or switch the current antipsychotic (if not clozapine) to aripiprazole.

Level of EvidenceLevel 4

EvidenceEvidence is from open-label studies and case series showing improvement in OC symptoms with SRI or aripiprazole augmentation without worsening psychosis. No large controlled trials exist for this population.

For practiceSRIs and/or aripiprazole can be added to an antipsychotic regimen to treat comorbid OC symptoms.

CaveatConsider CBT/ERP if the patient's clinical state makes it feasible.

p. 16 · Comorbidity Treatment

In patients with OCD seeking a remote psychotherapy option, offer internet-delivered CBT/ERP (ICBT).

Line / Strengthis effective

Level of EvidenceLevel 1

EvidenceEfficacy is supported by several RCTs and meta-analyses showing superiority over inactive controls and non-inferiority to in-person CBT for many patients. Therapist-guided ICBT appears more effective than purely self-guided versions.

For practiceICBT is a valid and accessible first-line psychotherapy option for many OCD patients.

CaveatIn-person CBT is recommended for patients with higher OCD symptom severity.

p. 28 · Psychotherapy

In patients with an inadequate response to a full course of ERP, augment ERP with an SSRI or switch to an SSRI.

Line / Strengthare recommended

Level of EvidenceLevel 4

EvidenceThis recommendation is based on expert consensus and extrapolation from combination therapy trials. While there are no direct RCTs testing SRI augmentation after failed ERP, the known efficacy of SRIs makes this a logical next step.

For practiceFor ERP non-responders, initiating pharmacotherapy is a key next step.

CaveatSwitching to an SSRI has slightly higher quality evidence (Level 3) than augmenting (Level 4).

p. 28 · Psychotherapy

In patients with treatment-resistant OCD, consider a trial of high-dose SSRIs.

Line / Strengthsecond-line option

Level of EvidenceLevel 2

EvidenceTwo controlled studies in partial or non-responders found positive results and good tolerability for sertraline (up to 400 mg) and escitalopram (up to 40 mg). A meta-analysis also supports a dose-response relationship for SSRIs in OCD.

For practicePushing the SSRI dose above standard limits is a valid strategy in treatment-resistant OCD.

CaveatThis strategy should be considered after failure of standard-dose SSRIs but before or alongside augmentation.

p. 33 · Treatment Resistant OCD - Serotonergic Agents

SOURCE GUIDELINE

2025 international guidelines for the management of patients with obsessive-compulsive disorder

Canadian Network for Mood and Anxiety Treatments (CANMAT) / International College of Obsessive-Compulsive Spectrum Disorders (ICOCS)

Year2025

TypeFull Guideline

JournalJournal of Psychiatric Research

DOI10.1016/j.jpsychires.2025.12.039