What is Exposure and Response Prevention (ERP)?
ERP is the first-line treatment for obsessive-compulsive disorder – and one of the most thoroughly researched methods in CBT. Here's how it works, why it works, and what a treatment looks like.
Psyklinisk editorial team
Clinicians & CBT educators
Exposure and Response Prevention (ERP) is the evidence-based first-line treatment for obsessive-compulsive disorder (OCD) and is recommended in the national guidelines from Sweden's National Board of Health and Welfare. The method is easy to describe and hard to carry out: the patient faces what they fear, but refrains from the compulsive behaviour that would normally lower their anxiety. Here's how it works and how it can improve everyday functioning.
What is OCD, briefly
Obsessive-compulsive disorder (OCD) has two parts. Obsessions are intrusive, unwanted thoughts, images or urges (for example, "I might have contaminated my hands", "what if I've hurt someone", "did I turn the stove off?"). Compulsions are what the patient does to lower the anxiety – washing hands, checking, repeating, mentally going through the situation. The behaviour brings short-term relief, but in the long run reinforces both the obsessions and the anxiety.
Why does ERP work?
Compulsions can produce short-term relief that reinforces the behaviour. ERP provides opportunities to face triggers without following rituals, learning to tolerate uncertainty and distress and manage situations without compulsions. Anxiety may decrease but does not need to fall during every exercise for exposure to be useful.
What does an ERP treatment look like?
Assessment and psychoeducation (sessions 1–2)
The therapist and patient map out obsessions, compulsions, avoidances and functional impairment. The Y-BOCS is used to measure symptom severity. The patient is given an explanation of how OCD works – and why what they themselves do (washing, checking, seeking reassurance) keeps the problem alive.
Exposure hierarchy (sessions 2–3)
Together, a ladder of situations is built, from mild (touching a door handle and refraining from washing for 15 minutes) to difficult (refraining from extra washing rituals after ordinary handwashing). Each step is given an expected anxiety rating of 0–100.
Active exposure (session 4 onwards)
This is where the actual treatment takes place. The patient and therapist carry out exposures together: often within the session and always as homework. The rule is simple: expose yourself to what triggers the compulsion, and refrain from both outward compulsions and mental neutralising. Anxiety usually rises at the start of the exercise and then subsides, but what matters is that the patient stays in the situation without rituals.
Relapse prevention and discharge (sessions 14–20)
In the final sessions, the therapist works on generalisation (helping the patient create their own new exposures), relapse-prevention work, and a written plan for how to handle setbacks.
Concrete examples
- Contamination: Touch an ordinary door handle and refrain from additional compulsive handwashing. Plan exposures individually and follow reasonable hygiene and safety practices.
- Checking: Locking the door once and walking straight off without going back to check. The patient notes the worry and refrains from checking.
- Symmetry/order: Deliberately placing items askew on the desk and leaving them that way for the whole working day.
- Harm-related obsessions: Reading violent news stories and refraining from mental neutralising or seeking reassurance from loved ones.
How effective is ERP?
CBT with ERP has strong evidence for OCD and is recommended with high priority in Socialstyrelsen’s national guidelines. Outcomes vary between studies and patients. SSRIs are another option, and combined treatment may be considered following individual assessment.
Common mistakes in ERP
- Progressing too slowly – the patient stays too long on easy exposures, so the situation never feels like a real threat.
- Mental compulsions are missed – the patient "does nothing" outwardly but neutralises mentally, which renders the exposure ineffective.
- The therapist seeks to reassure the patient too quickly during exposure ("think about how safe this is") – which becomes a form of reassurance-seeking.
- Homework isn't done – regular practice between sessions needs to fit the patient’s circumstances.
When is ERP suitable – and when isn't it?
ERP is the first-line treatment for all forms of OCD in which the patient can identify obsessions and compulsions. When compulsions are mental, identify them and include them in response prevention. Imaginal exposure may form part of treatment but does not replace addressing mental rituals. In severe depression, active suicidality or ongoing substance misuse, ERP may need to wait until other conditions have stabilised. Adaptations are also required for autism and intellectual disability.
Frequently asked questions
› Is ERP the same as exposure therapy?
ERP combines exposure with refraining from compulsions, including mental rituals. Exposure is also used for other anxiety disorders, where reducing avoidance and safety behaviours is often important. Other exposure therapies do not necessarily lack this behavioural element.
› Can you do ERP yourself with a self-help book?
Mild to moderate forms can improve with structured self-help, often combined with brief guidance from a therapist. For more severe OCD, full ERP with a CBT therapist is recommended, sometimes combined with an SSRI.
› How many sessions does it usually take?
14–20 sessions is common. For severe OCD, longer treatment may be needed, sometimes with intensive treatment over a shorter period.
Learn ERP in our Step 1
ERP is a core method in Psyklinisk's Step 1. You'll get both theory and case-based training in OCD treatment under supervision.
This article was compiled by Psyklinisk's editorial team for information and educational purposes and does not replace medical or psychological assessment, diagnosis or treatment. Always consult a doctor, psychologist or other licensed healthcare professional about your own concerns.
