What is ERP?
Exposure and response prevention (ERP) is a specific form of CBT designed for obsessive-compulsive disorder (OCD). NICE recommends CBT that includes ERP as the psychological treatment for OCD.
The principle is straightforward: you gradually face the situations that trigger your obsessions (exposure) while choosing not to perform your usual compulsive responses (response prevention). Over time, your brain learns that the feared outcome does not happen and the anxiety naturally reduces.
How it works
OCD operates as a cycle. An intrusive thought triggers anxiety. A compulsive behaviour temporarily relieves that anxiety. But the relief is short-lived, and the cycle strengthens each time it repeats. ERP breaks this cycle.
Your therapist will help you:
- Map your OCD: identify your obsessions, compulsions and avoidance behaviours
- Build a hierarchy: rank feared situations from least to most anxiety-provoking
- Begin exposures: start with manageable challenges and work upward
- Prevent the response: resist the urge to perform compulsions during and after exposure
- Process the experience: discuss what happened and what you learned
The key insight is that anxiety peaks and then naturally falls on its own, without the compulsion. Each successful exposure teaches your brain something new.
- Exposure You face an agreed situation, thought or object that brings up fear.
- Response prevention You practise resisting the compulsion you would usually use to reduce that fear.
Your therapist supports the work. ERP combines exposure with response prevention; exposure alone is only one part.
Source: NICE: OCD full guideline
What sessions look like
ERP typically runs for 12 to 20 sessions, though complex OCD may need more. Sessions last 60 to 90 minutes, longer than standard therapy, because exposures need enough time for anxiety to rise and begin falling naturally.
Early sessions focus on understanding your OCD and building your hierarchy. Your therapist will explain the rationale thoroughly before any exposures begin. Nothing is forced on you, and the pace is collaborative.
Exposures can be:
- In vivo: facing real-life situations (touching a doorknob without washing, leaving the house without checking the lock)
- Imaginal: vividly imagining feared scenarios when real-life exposure is not possible or ethical
- Interoceptive: deliberately triggering physical sensations associated with anxiety
Between sessions, you will practise exposures on your own. This homework is essential. The skills need to transfer from the therapy room into your daily life.
Who is it best suited to?
ERP is specifically designed for OCD, but it is also used for:
- Health anxiety (hypochondria)
- Body dysmorphic disorder (BDD)
- Specific phobias
- Some anxiety disorders with avoidance patterns
- Hoarding disorder
It is particularly important to seek an ERP-trained therapist if you have OCD, because NICE recommends CBT that includes ERP rather than general therapy. Öst and colleagues (2015) pooled 37 trials of CBT for OCD and found very large effects against waiting lists and placebo, and no significant difference between ERP and cognitive therapy.
How it differs from other approaches
ERP is more targeted than general CBT. While CBT might explore the thoughts behind your anxiety, ERP focuses on changing your behavioural response to those thoughts. The learning happens through direct experience, not through cognitive restructuring alone.
Unlike psychodynamic therapy, ERP does not explore the origins of your OCD. The question is not why you have these intrusive thoughts but how you respond to them. Most people have bizarre or disturbing intrusive thoughts; OCD is about the meaning you attach to them and the compulsions that follow.
If the intrusive thoughts began after a frightening event and come with flashbacks or nightmares, the pattern may be trauma rather than OCD. Our trauma and PTSD page and trauma-focused CBT cover that route.
ERP can feel challenging because it involves deliberately facing discomfort. A good therapist will move at your pace and stay within what you have agreed to.
The evidence
ERP has a large evidence base for OCD. The foundational work by Foa and Kozak (1986) on emotional processing of fear established the theoretical basis. Öst and colleagues' 2015 meta-analysis of studies spanning two decades found very large effect sizes for CBT against waiting lists and placebo. NICE recommends CBT that includes ERP as the psychological treatment for OCD, and it is available through NHS Talking Therapies in England.
Modern research by Craske and colleagues (2014) on inhibitory learning has refined how exposures are designed. The field continues to improve how ERP is delivered.
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- I think I have OCD
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References
- Foa, E. B. & Kozak, M. J. (1986). Emotional processing of fear: Exposure to corrective information. Psychological Bulletin. doi:10.1037/0033-2909.99.1.20
- 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. doi:10.1016/j.cpr.2015.06.003
- NICE (2005). Obsessive-compulsive disorder and body dysmorphic disorder: treatment (CG31). nice.org.uk
- Craske, M. G., Treanor, M., Conway, C. C., Zbozinek, T. & Vervliet, B. (2014). Maximizing exposure therapy: An inhibitory learning approach. Behaviour Research and Therapy. doi:10.1016/j.brat.2014.04.006
- NICE (2006). Obsessive compulsive disorder: full guideline. nice.org.uk
