Exposure and Response Prevention (ERP) Therapy for Obsessive-Compulsive and Related Disorders
Exposure simply means facing or confronting one's fears repeatedly until the fear subsides (called habituation, see below). Response prevention means refraining from compulsions, avoidance, or escape behaviors. For example, suppose a person with obsessive-compulsive disorder (OCD) has germ contamination phobia. A typical exposure exercise consists of shaking hands with someone (exposure), and not washing hands afterwards (response prevention). For body dysmorphic disorder (BDD), a typical exposure exercise might be going to a crowded shopping mall, without makeup or a hat (exposure) but not looking in any mirrors or reflective surfaces (response prevention).
Exposure Therapy: The effectiveness of exposure therapy relies upon a behavioral principle called habituation. Habituation is the process by which a person's behavioral and sensory response diminishes over time, after repeated exposure to a particular stimulus. We all have experienced habituation. Have you ever jumped into an ice cold swimming pool, only to feel comfortable after a few minutes? That's habituation at work. Perhaps you have friends who live nearby an airport, busy highway, or a train station. Have you wondered how they could possibly concentrate or sleep with all that noise? Your friends may have felt the same way when they first moved in. Now, after living there for a while, their sensory neurons just stopped reacting to the noise. They will probably tell you that they are so accustomed to the noise they no longer even hear it anymore. They've become habituated to it.
Exposure therapy takes advantage of this principle of habituation. In the context of treatment, it means allowing repeated exposure to the feared object or situation, so that habituation can occur.
Habituation via exposure is achieved by intentional choice. Overtime, the intensity of exposure is gradually increased. For instance, people with OCD who fear germ contamination may first touch a doorknob in the therapist's office. They allow themselves to experience the fear until it subsides, as habituation takes over. Then, the intensity or difficulty of the exposure is gradually increased. So, the therapist might take them to a department store. They would practice touching more things, handled by more people. With the support of the therapist, they would allow themselves to experience the fear until habituation occurred and the fear subsided. The next level of intensity might be to touch a doorknob in a public bathroom, etc. A similar process of gradual exposure with increasing intensity is used with hoarding disorder. First, a person might be asked to throw away one item from a small box. Next, they might be asked to throw away an entire box, and so on.
Exposure therapy may be conducted using in vivo exposure (meaning real live exposure to the feared stimulus). Alternatively, it may be conducted using imagination. Regardless of the method, individuals are encouraged to repeatedly face the anxiety-producing stimulus until habituation occurs.
Once habituation occurs, the fearful response is diminished and will eventually be extinguished. This concept is based on the principles of learning theory (specifically, classical conditioning). Research has demonstrated that individuals learn to become afraid of neutral stimuli (e.g., doorknobs). This occurs because a paired association forms between a neutral, conditioned stimulus (CS) and fear-inducing stimuli (UCS). A behavior will be extinguished, (i.e., the fear is eliminated), by reversing that process. In other words, people can unlearn their fear simply by decoupling the paired association between the fear and the neutral stimulus (CS). For example, a person with germ contamination may have formed a paired association between fear and doorknobs (CS). As a result, he or she may avoid touching doorknobs directly. Through exposure therapy, the person would repeatedly touch doorknobs until habituation occurs. Because the doorknobs (CS) no long produce a fearful response (due to habituation), the association between the doorknob and fear has been decoupled. As such, the fearful response is gradually eliminated or extinguished. Through repeated exposure, the person learned something new: Nothing terrible happened as a result of touching the doorknob.
Response Prevention: Exposure therapy is usually coupled with response prevention. This is also known as "ritual prevention." This component of treatment is particularly important for people who have developed ritualized, repetitive behaviors such as compulsions. The compulsive behavior serves to "undo" or neutralize the anxiety that occurs when faced with an anxiety-provoking situation. Since compulsive behaviors serve to reduce or eliminate anxiety they are intrinsically rewarding. Therefore, they are repeated.
Response prevention is based on a principle of learning theory (specifically, operant conditioning). According to this principle, when a behavior is no longer rewarded (reinforced) it becomes extinct. This means the behavior gradually fades away. For instance, washing hands after contact with a doorknob serves to "undo," or negate the anxiety that occurs after touching a doorknob. Response prevention eliminates the rewarding effect of hand washing. As such, compulsive hand washing will gradually become extinct.
Escape and avoidance behaviors serve the same rewarding function as compulsive rituals. You may recall that escape and avoidance are protective coping strategies that reduce anxiety in the short-term. Since anxiety is reduced by avoiding or escaping anxiety-provoking situations, these avoidance behaviors are rewarded. Since escape and avoidance behaviors are rewarded by the reduction of anxiety, the avoidance behaviors continue.
The elimination (extinction) of rewarded behaviors (compulsive rituals, escape, and avoidance) cannot be achieved unless these behaviors are prevented. Response prevention prevents these behaviors from being rewarded. Once a behavior is no longer rewarded, it stops. Response prevention is a necessary component of behavioral therapy in the treatment of obsessive- compulsive disorder, body dysmorphic disorder, and hoarding. The combination of exposure to anxiety-provoking stimuli, along with the prevention of rituals, escape, or avoidance leads to the most effective treatment response.
It should be evident that exposure and response prevention therapies require the willingness to tolerate some discomfort until habituation develops. Therapy participants voluntarily choose to participate in this type of therapy. They are well-prepared in advance of the therapy. At no point is anyone forced or coerced to participate in the exercises. If it becomes too difficult to complete an exercise, the process is stopped. Then, the therapist and participant discuss what happened. Sometimes the therapy participant is ready to try again. At other times, the therapist may switch approaches and work toward increasing motivation for treatment. The therapy is most effective when conducted with the therapist guiding the patient during therapy sessions, coupled with follow-up homework assignments.