Obsessive-Compulsive Disorder (OCD)

The short version

●OCD is defined by obsessions (intrusive, unwanted thoughts, images, or urges) and/or compulsions (repetitive behaviors or mental acts done to neutralize the distress) that consume more than an hour a day or cause marked impairment.
●First-line treatment is exposure and response prevention (ERP) therapy plus an SSRI — but OCD needs higher SSRI doses and longer trials (10-12 weeks) than depression.
●Roughly 40-60% of patients do not achieve adequate response to first-line SSRI plus ERP; OCD is among the more treatment-resistant conditions in psychiatry.
●Ketamine is mechanistically relevant because glutamatergic dysregulation in cortico-striatal circuits is implicated in OCD, and ketamine acts directly on that system.
●A randomized controlled crossover trial (Rodriguez 2013) found a single ketamine infusion rapidly reduced obsessions versus saline — proof-of-concept, though durability beyond days was limited.
●Ketamine is not first-line for OCD; it is considered for treatment-resistant cases, especially with comorbid treatment-resistant depression, and works best paired with ERP.

Clinical definition

OCD is characterized by obsessions — recurrent, persistent, intrusive thoughts, images, or urges that cause marked anxiety — and/or compulsions — repetitive behaviors (checking, washing, ordering) or mental acts (counting, praying, silently repeating) performed to reduce that anxiety or prevent a feared outcome. DSM-5 requires that these consume more than one hour per day or cause clinically significant distress or impairment. Insight varies and can be poor. Common symptom dimensions include contamination/washing, harm/checking, symmetry/ordering, and taboo intrusive thoughts (aggressive, sexual, religious). DSM-5 classifies OCD under "Obsessive-Compulsive and Related Disorders," separate from the anxiety disorders, reflecting its distinct cortico-striato-thalamo-cortical circuit involvement.

How it differs from related conditions

vs. Generalized anxiety disorder

GAD worries concern real-life problems (money, health, work) and feel ego-syntonic; OCD obsessions are typically irrational, intrusive, and ego-dystonic, paired with ritualized compulsions to neutralize them.

vs. Obsessive-compulsive personality disorder (OCPD)

OCPD is a pervasive personality style of perfectionism, control, and rigidity experienced as ego-syntonic (the person sees it as correct); OCD involves distressing, unwanted obsessions and compulsions the person wants to be rid of.

vs. OCD-spectrum disorders (BDD, hoarding, trichotillomania)

Related disorders with overlapping circuitry but distinct content; distinguishing matters because treatment protocols differ.

vs. Psychotic disorders

Poor-insight OCD can resemble delusions, but OCD obsessions are recognized as one's own thoughts and resisted, unlike fixed delusional beliefs.

First-line treatments

Exposure and response prevention (ERP)

The most effective psychotherapy for OCD: the patient is exposed to the feared trigger and refrains from the compulsion, allowing anxiety to habituate. Manualized, typically 12-20 sessions; effect sizes exceed medication alone for many patients.

SSRIs at high dose

Fluoxetine, sertraline, fluvoxamine, paroxetine, escitalopram. OCD requires higher doses and longer trials (10-12 weeks) than depression; about 40-60% achieve a meaningful response.

Clomipramine

The most serotonergically potent agent for OCD, with strong evidence; reserved for when SSRIs fail because of its side-effect burden.

Antipsychotic augmentation

Low-dose risperidone or aripiprazole added to an SSRI for partial responders, particularly with tic-related or poor-insight OCD.

When standard treatments fail

Treatment-resistant OCD is inadequate response to at least two adequate SSRI trials (high dose, 10-12 weeks) plus a genuine course of ERP. The escalation sequence: confirm ERP was truly adequate (the most common reason for apparent failure is under-dosed or incomplete exposure work) → switch SSRI or move to clomipramine → antipsychotic augmentation → consider glutamatergic agents and, in severe refractory cases, neurosurgical options (deep brain stimulation, gamma-knife capsulotomy) at specialized centers. Ketamine and other rapid-acting glutamatergic interventions are an active research area for the refractory subgroup.

Where ketamine fits

Ketamine is not a first-line OCD treatment, and the OCD-specific evidence base is small. Its relevance is mechanistic: glutamatergic dysregulation in cortico-striatal circuits is implicated in OCD, and ketamine acts directly on that system. A randomized, placebo-controlled crossover trial (Rodriguez 2013, Neuropsychopharmacology) found that a single ketamine infusion produced a rapid reduction in obsessions in patients with constant, distressing obsessional thoughts — the first controlled signal that NMDA antagonism can move OCD symptoms acutely. The main limitation is durability: the effect was measured over days, and OCD is a chronic, ritual-reinforced condition where lasting change typically requires concurrent ERP. Clinically, ketamine is most reasonable for OCD patients who also have treatment-resistant depression (a very common comorbidity) or who have exhausted SSRIs, clomipramine, ERP, and augmentation. The most promising models pair ketamine with ERP, using the post-session neuroplastic window to make exposure work more tolerable.

Where this fits with Tovani

Tovani treats OCD when it co-occurs with treatment-resistant depression, or after adequate first-line OCD care (high-dose SSRI plus ERP) has failed. Because durable OCD improvement generally requires ERP, Tovani encourages patients to maintain or begin ERP with a skilled OCD therapist alongside ketamine — the medication can lower the distress that makes exposure work feel impossible, but it does not replace it. Eligibility screening captures OCD symptom severity, prior treatment, and comorbid depression. Patients with isolated OCD and no adequate first-line trials are generally referred to first-line care before ketamine is appropriate.

Check eligibility The science behind ketamine

Frequently asked

Does ketamine cure OCD?

No. The controlled evidence shows ketamine can rapidly reduce obsessions for some patients, but the effect measured so far is short-lived (days). Durable OCD improvement still depends on exposure and response prevention (ERP) therapy. Ketamine is best thought of as a potential accelerator for treatment-resistant OCD, especially with comorbid depression — not a standalone cure.

Why do SSRIs need higher doses for OCD?

OCD typically responds only at the higher end of the SSRI dose range and needs 10-12 weeks to judge — longer than the 4-8 weeks for depression. Many "SSRI failures" in OCD are actually under-dosed or too-short trials.

Is ERP really necessary?

For lasting change, yes. ERP is the single most effective OCD treatment, and combining it with medication outperforms medication alone. Ketamine may make ERP more tolerable but does not substitute for it.

Can I get ketamine for OCD if I also have depression?

This is the most appropriate scenario. When OCD coexists with treatment-resistant depression, ketamine targets the depression directly and may reduce obsessional distress, while ERP addresses the OCD. Tovani screens for this during eligibility.

References

Stein DJ et al. 2019, Nature Reviews Disease Primers — Comprehensive review of OCD: phenomenology, cortico-striatal circuitry, and the evidence base for ERP, SSRIs, clomipramine, and augmentation. (PMID 31371720)
Rodriguez CI et al. 2013, Neuropsychopharmacology — Randomized controlled crossover trial of ketamine in OCD; a single infusion produced a rapid reduction in obsessions versus saline. (PMID 23783065)
Sanacora G et al. 2017, JAMA Psychiatry — American Psychiatric Association consensus on the clinical use and safety of ketamine across complex psychiatric presentations. (PMID 28249076)

Last reviewed by Dr. Ben Soffer, DO on May 30, 2026. This page is educational and not a substitute for clinical evaluation. A physician determines whether ketamine therapy is appropriate for your specific situation.