What Is Exposure and Response Prevention (ERP) Therapy?

Exposure and Response Prevention (ERP) Therapy is a type of Cognitive Behavioral Therapy (CBT) considered the first line of psychotherapy for OCD (Hezel & Simpson, 2019).

ERP is highly effective. But the commonly quoted 75-85% success rate needs context. In the field’s landmark trial, 86% of patients who completed treatment responded (Foa et al., 2005). Counting everyone who started, the response rate was 62%.

ERP therapy aims to gradually reduce the anxieties associated with OCD and interrupt the problematic obsession-compulsion cycle. ERP therapy is not about eliminating your distress but rather about learning how to accept and manage it without neutralizing it.

ERP therapy involves therapist-guided, systematic exposure to situations that provoke obsessional fears. It also requires abstaining from the usual compulsive behaviours. Exposures are repeated and prolonged.

The goal is for the patient to deliberately confront feared situations and stimuli they usually avoid, such as public bathrooms or crowded spaces. This confrontation is meant to trigger the same obsessional fears and urges that used to lead to ritualising.

Compulsions come next. After exposure, patients are instructed to avoid performing them, such as washing, counting, or arranging and ordering objects.

Over the last 30 years, ERP for OCD has been studied worldwide. Trials involving over 500 patients and numerous therapists confirm that its benefits generalise across settings (Abramowitz, 2006).

How Does ERP Therapy Work?

ERP works by breaking the link between obsessional thoughts and the compulsions used to relieve them. Patients gradually face situations that trigger their obsessions while resisting the urge to carry out the usual compulsion.

By staying in a feared situation and leaning into the discomfort and uncertainty, patients learn that they don’t need their compulsions to cope, and that their fearful thoughts have no power over them.

Breaking the Obsession-Compulsion Cycle

Compulsions persist because they work, in the short term. Performing a ritual removes the anxiety an obsession creates, and that relief is rewarding.

Psychologists call this operant negative reinforcement: a behaviour that removes something unpleasant gets repeated. The ritual always comes first.

It happens before the anxiety could fall on its own. So two things never get learned: that the anxiety would have eased anyway, and that the feared outcome would not have happened.

Avoidance works the same way. Staying away from a trigger altogether spares the anxiety spike, but it also means the feared belief never gets tested and never gets disproven.

ERP blocks the ritual on purpose. With the compulsion prevented, patients discover both of those facts for themselves.

Habituation and New Learning

Staying in a feared situation without ritualising triggers habituation, a natural decline in fear the longer a trigger is faced without the usual escape. As anxiety habituates, the learned link between the obsession and the compulsion weakens.

Each exposure gets easier. Patients start with manageable situations and work up to harder ones as their confidence grows.

More recent research adds a second piece to this picture. Exposure seems to work best when it lets you discover that your prediction was wrong, not simply when your anxiety falls.

ERP takes time, effort and practice. But it directs patients to live with the anxiety and discover that nothing bad happens, rather than avoiding it forever.

ERP is best undertaken with a practitioner trained to work with OCD, who can help devise a plan and support you in carrying it out safely.

How Is ERP Therapy Delivered?

People with OCD often seek 100% assurance that their fear won’t come true. But we can never be completely certain of anything.

In ERP, patients will be taught to face their fears and then wait, instead of acting on them. Eventually, they will develop the ability to tolerate the uncertainty around their fears. Building this relationship with uncertainty is the only way to overcome OCD. 

1. Assess the individual’s symptoms

The first step of ERP is working with a therapist to identify and assess your symptoms. Together, you will name your obsessions, intrusive thoughts, urges and compulsive rituals.

Tracking your symptoms like this has a second benefit. It shows you how much OCD affects your daily life, which can motivate you to keep going with treatment.

Next comes the hierarchy. You and your therapist list your triggers and feared situations, then rank them from least to most distressing.

Distress is usually rated on a 0-100% scale, from completely relaxed to the worst anxiety imaginable. This is the Subjective Units of Distress Scale, or SUDS.

Here is an example of an exposure hierarchy for a patient who fears contamination.

1. Handling money (SUDS rating: 50)
2. Pressing a button on a vending machine (SUDS rating: 55)
3. Touching the bottom of your shoe (SUDS rating: 60)
4. Shaking hands with a stranger (SUDS rating: 65)
5. Touching bathroom door handle (SUDS rating: 75)
6. Touching wall in toilet (SUDS rating: 80)
7. Handling raw poultry or hamburger meat (SUDS rating 85)
8. Touching floor beside toilet (SUDS rating: 90)
9. Touching toilet seat (SUDS rating: 95)
10. Putting hand in toilet bowl water (SUDS rating: 100)

2. Psychoeducation

Psychoeducation involves learning about OCD and its symptoms, treatments, treatment effectiveness, and other research.

This education is vital because patients often do not realize that struggling against their intrusive thoughts will only worsen them.

Psychoeducation can also help patients maintain their motivation through treatment. They might write a statement about why it’s worth recovering, write out the advantages/disadvantages of stopping compulsions, or discuss with their therapist their goals for treatment. 

Understanding OCD Better

People report that learning more about OCD, especially how avoiding things and doing rituals keeps the OCD going, changes how they think about their symptoms. This knowledge can give them the push to start Exposure and Response Prevention (ERP) exercises.

“Even though I sometimes still feel guilty, I’m trying not to do my rituals because I know they don’t really help – it’s just the OCD controlling me.”

Source: Leeuwerik, T., Caradonna, & Strauss, C. (2023). A thematic analysis of barriers and facilitators to participant engagement in group exposure and response prevention therapy for obsessive–compulsive disorder. Psychology and Psychotherapy: Theory, Research and Practice, 96(1), 129-147.

Why Treatment Works

People report that understanding how and why ERP helps was encouraging. For example, learning that natural reactions, like fear, will fade over time if we face them.

This made some, like Helen, want to confront their OCD head-on: “… it made me eager to face it rather than just think about it.” Isabel felt empowered, saying, “I realized I can face something that scares me, and with time, it won’t be as scary anymore.”

Source: Leeuwerik, T., Caradonna, & Strauss, C. (2023). A thematic analysis of barriers and facilitators to participant engagement in group exposure and response prevention therapy for obsessive–compulsive disorder. Psychology and Psychotherapy: Theory, Research and Practice, 96(1), 129-147.

3. Exposure

This is the action component of ERP. It involves purposely being exposed to triggers in a gradual, moderated way.

Exposure therapy can progress at different paces for different individuals depending on the severity of the OCD and the fear(s) associated with the patient’s OCD.

Graded Exposure

Graded exposure involves exposing yourself to the source of your fear gradually by going up the hierarchy one step at a time.

Your therapist guides you through the fear hierarchy, starting with items that give you at least 50-60% anxiety. You and your therapist decide together when to move from one situation to the next.

Each new goal will still feel somewhat anxiety-inducing. But as you learn to manage your intrusive thoughts, that anxiety arises less often and with less power.

Repeated Exposure

Exposure must be repeated. It is important that you practice facing your fears many times until you feel comfortable in that situation.

You repeat each step until it no longer goes above 40% anxiety at the start of the exercise.

Then you move up.

Once a step stops feeling anxiety-inducing, you’re ready for the next one on your hierarchy.

Prolonged Exposure

Prolonged exposure means staying in the feared situation, without carrying out a compulsion, until your anxiety drops by 50% from where it started. This usually takes 45 to 90 minutes.

For example, if you started at 85% anxious, you would stay until your anxiety fell to at least 35%. You would then repeat the exercise until it no longer rose above 40% at the start.

4. Response prevention

Response prevention is one of the main components of ERP therapy. It means refraining from compulsions or avoidance behaviours whenever you are exposed to a trigger. That refraining is deliberate, and it is intentional.

Compulsions, or rituals, are behaviors that people with OCD perform in response to an obsession, or intrusive thought. People perform these compulsions to suppress their anxiety and neutralize their fears.

However, while compulsions might “help” in the short term, they only make the intrusive thoughts worse and serve to keep the OCD cycle going long-term.

Tolerating uncertainty

Low tolerance to uncertainty is a primary feature of the obsession-compulsion cycle. People who suffer from OCD believe that their distressing thoughts will become a reality, so they engage in compulsions to prevent this from happening.

Writer and mental-health campaigner Lily Bailey describes this struggle from the inside, in her memoir Because We Are Bad: OCD and a Girl Lost in Thought (2016).

Her compulsions were mostly mental. She silently confessed ‘bad’ thoughts and repeated rituals to feel ‘clean’ inside.

As she recounts it, stopping the rituals was the hardest part of recovery. It was also the most crucial step. She had to simply tolerate the uncertainty they were meant to resolve.

This is one person’s experience, not evidence about ERP in general. But it illustrates why tolerating uncertainty is the treatment’s active ingredient.

Delaying rituals

In ERP, a therapist might ask a patient to start by delaying their responses to triggers. This increases the time between the obsessive thought and performing the compulsion.

Overtime, this will progress until a patient is resisting the compulsion altogether.

Modifying rituals

In addition to delaying their responses, patients will also be challenged to modify their rituals. That way, they can still act on their thoughts but not in the same ways that they are typically inclined to do.

Exposure Without Distraction

This step involves avoiding doing things that serve to reduce your anxiety artificially or distract you from how you are feeling during your exposure exercises.

These temporary reliefs are only keeping you stuck in the vicious OCD cycle.

Exposure Without Compulsion

Each time you expose yourself to an exercise on your hierarchy, you need to resist the urge to carry out a compulsion to neutralize or reduce your distress. This final condition is critical to making your ERP effective.

Patients are encouraged to focus their attention on simply noticing what happens as they are exposed, while not performing a compulsion to cope (i.e., not seeking reassurance, neutralizing, or checking).

As Professor Edna B. Foa, the clinician who standardised ERP, explains in her therapist guide, treatment often fails for one reason. Response prevention is left incomplete.

She stresses that reassurance-seeking, mental reviewing and subtle avoidance are compulsions in disguise. Unless these covert rituals are blocked too, the anxiety never gets the chance to fall on its own.

Types of ERP Therapy

In Vivo Exposure

In vivo exposure means facing the feared object, situation or activity directly. It happens in real life, not imagination.

For example, someone with social anxiety might give a speech in front of an audience. Someone with contamination OCD might touch a doorknob and refrain from washing their hands afterwards.

Other examples exist too. Some patients leave the house without repeatedly checking the locks. Others deliberately write out a feared word. Exposures like these usually start in the moderate range of the hierarchy, moving to harder items as each is mastered.

Imaginal Exposure

Some feared consequences can’t be physically brought on. Imaginal exposure meets this by vividly imagining the feared object, situation or activity instead.

For example, someone with post-traumatic stress disorder might recall and describe their traumatic experience in detail. This is meant to induce, and eventually reduce, their fear.

Some people use scripting instead. They write out their worst fears as a detailed script, then reread or listen to it repeatedly, exposing themselves to the imagined scenario each time.

The goal is a first-person, present-tense, detailed narrative of the worst-case scenario occurring.

Interoceptive Exposure

Interoceptive exposure is the practice of strategically inducing the somatic symptoms associated with a threat appraisal and encouraging the patient to maintain contact with the feared sensations.

Examples of interoceptive exposures include spinning around on a swivel chair to simulate feelings of dizziness; breathing fast to recreate a racing heart; or running upstairs to simulate breathlessness.

This approach is particularly helpful in treating clients who fear the physical sensations accompanying their panic, anxiety, or phobia more than the event itself. It is generally employed when treating panic attacks. 

Virtual Reality Exposure

Virtual reality exposure is a more novel approach that involves confronting your fears using virtual reality. For example, for a patient who has a fear of flying, this type of exposure can use virtual reality to simulate flying in an airplane. 

Flooding

Flooding is another treatment approach that involves exposing a patient to the highest level of the hierarchy all at once.

Therapists tend to use flooding if a patient’s fear interferes with their ability to go about their daily life, and thus needs to be handled more aggressively.

Flooding can help a patient overcome their fear faster, but it can also be traumatic and overwhelming to experience.

Flooding is the opposite of graded exposure, where a patient is exposed to their fears gradually by going up the hierarchy one step at a time. 

How Effective Is ERP Therapy?

ERP is one of the most well-supported psychological treatments available. But the headline efficacy figures often quoted online overstate what the average patient can expect.

A landmark trial randomly assigned 122 adults with OCD to intensive ERP, the medication clomipramine, both combined, or a placebo pill (Foa et al., 2005).

The results were clear. Among patients who completed treatment, 86% responded to ERP, similar to combined treatment and far above medication alone.

That 86% figure is where the commonly quoted “75-85% efficacy” claim comes from. It only counts people who finished treatment. Counting everyone who started, including dropouts, the same trial’s response rate was 62%.

A 2015 review pooled 37 controlled trials. It found similarly large effects: ERP and cognitive therapy each beat a waiting list or a placebo by a wide margin, and outperformed antidepressant medication alone (Öst et al., 2015).

ERP has a reputation for being too distressing to finish. The evidence does not support this.

A 2016 review of 21 controlled trials, covering around 1,400 patients, found an average ERP dropout rate of 14.7%. That is no higher than for gentler-sounding therapies like cognitive therapy (Ong et al., 2016). Most patients who start ERP do stay with it.

ERP does not work for everyone, though. A meaningful minority of patients respond only partially, especially those with severe or long-standing OCD, poor insight, or hoarding symptoms. Options then include adding or switching to SSRI medication, longer or more intensive ERP, or, in severe cases, neuromodulation.

Contemporary Research

A 2016 network meta-analysis pooled 54 trials and 6,652 patients. It compared every OCD treatment, psychological and pharmacological, on one scale (Skapinakis et al., 2016).

Behavioural therapy, essentially ERP, produced the largest effect of any treatment tested. It beat cognitive therapy and left medication far behind.

The authors were candid about the limits of this finding. The behavioural-therapy trials were relatively small. Most also let patients keep taking antidepressants alongside therapy, which muddies the comparison. In severe OCD, they concluded, combining therapy and medication likely works better than either alone.

A separate, stricter reanalysis adds a further caution. ERP’s advantage over other active therapies shrank toward non-significance in trials without a researcher stake in the outcome (Reid et al., 2021). This does not overturn ERP’s first-line status. But it is a reminder that even a gold-standard therapy deserves ongoing scrutiny.

FAQs

Sources

Abramowitz, J. S. (2006). The psychological treatment of obsessive—compulsive disorder. The Canadian Journal of Psychiatry, 51(7), 407-416.

Foa, E. B., Liebowitz, M. R., Kozak, M. J., Davies, S., Campeas, R., Franklin, M. E., Huppert, J. D., Kjernisted, K., Rowan, V., Schmidt, A. B., Simpson, H. B., & Tu, X. (2005). Randomized, placebo-controlled trial of exposure and ritual prevention, clomipramine, and their combination in the treatment of obsessive-compulsive disorder. American Journal of Psychiatry, 162(1), 151-161. https://doi.org/10.1176/appi.ajp.162.1.151

Foa, E. B., Yadin, E., & Lichner, T. K. (2012). Exposure and response (ritual) prevention for obsessive-compulsive disorder: Therapist guide. Oxford University Press.

Gellatly, J., Bower, P., McMillan, D., Roberts, C., Byford, S., Bee, P., … & Lovell, K. (2014). Obsessive Compulsive Treatment Efficacy Trial (OCTET) comparing the clinical and cost effectiveness of self-managed therapies: study protocol for a randomised controlled trial. Trials, 15, 1-10.

Hezel, D. M., & Simpson, H. B. (2019). Exposure and response prevention for obsessive-compulsive disorder: A review and new directions. Indian journal of psychiatry, 61(Suppl 1), S85.

Leeuwerik, T., Caradonna, G., Cavanagh, K., Forrester, E., Jones, A. M., Lea, L., … & Strauss, C. (2023). A thematic analysis of barriers and facilitators to participant engagement in group exposure and response prevention therapy for obsessive–compulsive disorder. Psychology and Psychotherapy: Theory, Research and Practice, 96(1), 129-147.

Ong, C. W., Clyde, J. W., Bluett, E. J., Levin, M. E., & Twohig, M. P. (2016). Dropout rates in exposure with response prevention for obsessive-compulsive disorder: What do the data really say? Journal of Anxiety Disorders, 40, 8-17. https://doi.org/10.1016/j.janxdis.2016.03.006

Öst, L. G., Havnen, A., Hansen, B., & Kvale, G. (2015). Cognitive behavioral treatments of obsessive-compulsive disorder: A systematic review and meta-analysis of studies published 1993-2014. Clinical Psychology Review, 40, 156-169. https://doi.org/10.1016/j.cpr.2015.06.003

Reid, A. M., Guzick, A. G., Balkhi, A. M., McBride, M., Geffken, G. R., & McNamara, J. P. H. (2017). The progressive cascading model improves exposure delivery in trainee therapists learning exposure therapy for obsessive-compulsive disorder. Training and Education in Professional Psychology, 11(4), 260–265.

Reid, J. E., Laws, K. R., Drummond, L., Vismara, M., Grancini, B., Mpavaenda, D., & Fineberg, N. A. (2021). Cognitive behavioural therapy with exposure and response prevention in the treatment of obsessive-compulsive disorder: A systematic review and meta-analysis of randomised controlled trials. Comprehensive Psychiatry, 106, 152223. https://doi.org/10.1016/j.comppsych.2021.152223

Skapinakis, P., Caldwell, D. M., Hollingworth, W., Bryden, P., Fineberg, N. A., Salkovskis, P., Welton, N. J., Baxter, H., Kessler, D., Churchill, R., & Lewis, G. (2016). Pharmacological and psychotherapeutic interventions for management of obsessive-compulsive disorder in adults: A systematic review and network meta-analysis. The Lancet Psychiatry, 3(8), 730-739. https://doi.org/10.1016/S2215-0366(16)30069-4