Obsessive-compulsive disorder (OCD) is a distressing and often challenging disorder to treat. As part of the evolution of cognitive behavioral therapy (CBT), exposure therapy for OCD developed as a targeted treatment approach addressing fear response. Exposure and response prevention therapy—also known as exposure therapy, or ERP—has significantly improved outcomes for OCD and is a first-line treatment for this disorder. While research support for exposure therapy is strong, there is still more left to learn about the mechanisms behind it, as well as why some achieve complete symptom remission through exposure therapy, while others show little to no response.
Read on to learn how exposure therapy evolved. Then review how ERP works as explained by understanding theoretical perspectives and more about the exposure process. Finally, learn about the efficacy of ERP and directions for the future.
Advancements of cognitive behavioral therapy (CBT) include a treatment called exposure and response prevention for OCD. ERP teaches individuals to face and tolerate distress from OCD-related stimuli without maladaptive behaviors, as well as challenging their fear response to triggers in their environment.
In addition to CBT, exposure therapy is based on the principles of classical conditioning, a behavioral approach that emphasizes observable behavior, rather than internal processes. Behaviorism was developed from the process of systematic desensitization, which includes elements of exposure and relaxation techniques. ERP similarly activates a corrective learning process, in which the meaning of the stimuli and fear responses are challenged and changed.
Research from the 1970s and 1980s found that individuals improved even when a relaxation component was not present. This led to the development of modern OCD/exposure therapy, with cognitive behavioral therapy/ERP eventually becoming the gold standard for OCD treatment.
Despite years of positive outcomes from exposure therapy for OCD, the mechanisms of change when treating this disorder are not yet clearly understood. However, it has been discovered that individuals with a significantly reduced emotional response in the first ERP session are likely to show greater OCD symptom improvement over the course of several more sessions. Two leading theoretical perspectives offer potential explanations for OCD symptom improvement following additional exposure therapy.
According to the emotional processing theory, memory structures store emotions, information about stimuli that elicit that emotion, the response itself, and the meaning behind each component. As such, a fear structure in OCD could include an association between doorknobs and deadly contamination.
Facing triggering stimuli, as part of exposure therapy presents a different outcome from the original fear structure, allowing for a new memory structure to form, with decreased emotional response or distress. The familiarization process to this new, beneficial outcome is called habituation. As the patient experiences less anxiety from facing triggering stimuli, and gains more and more memories of a reduced emotional response, the pathological structure they used to experience is weakened, and a more stable response takes its place.
Inhibitory learning proposes that exposure to triggering stimuli introduces a new association alongside the original, distressing association. This is achieved via expectancy violation, a moment when an individual has an unexpected outcome. For example, an individual with an association between doorknobs and contamination may begin to internalize that no actual harm comes when they touch a doorknob. This understanding would create a new association between doorknobs and a lack of contracting a deadly disease.
Both associations would continue to exist, with the more practiced response inhibiting the other and gaining prominence. The original association with deadly contamination can strengthen and reemerge at any time, necessitating ongoing practice and exposure of the realistic association to maintain inhibition of the deadly contamination association.
Exposure in EPR requires the creation of a fear hierarchy, which is a list of OCD-related stimuli in order from least to most distressing. This hierarchy is the foundation of the exposure process to gradually introduce stimuli at a level that is therapeutically challenging but tolerable enough to maintain progressive exposure. Individuals rate their anxiety connected to various stimuli using a Subjective Units of Distress Scale (SUDS) from 0 (least distressing) to 100 (most distressing).
The following sections illustrate examples of OCD symptom-inducing stimuli, as part of a suggested ERP fear hierarchy:
Exposure within EPR therapy can be done with one’s imagination (imaginal exposure) and in real life (in vivo exposure). In vivo exposure can provide powerful disconfirmation of an individual’s most feared outcome. They can see for themselves that touching a perceived contaminated item or holding a knife does not result in harm. However, in vivo exposure is not always safe or practical, as with fears related to traumatic events or severe weather. In these and other cases, imaginal exposure is another common exposure method.
Imaginal exposure for OCD helps dispel the belief that thoughts are the same as actions, and that imagining their worst fears will not make them materialize. One downfall of imaginal exposure is its use in situations where in vivo exposure is possible, safe, and perhaps more effective. When individuals do not see information that contradicts their worst fears, they may be reluctant to learn new associations without a fearful response.
As mentioned earlier, exposure therapy is considered a first-line treatment for OCD. Still, there may be instances where individuals may face significant discomfort during therapy or feel like the exposure was more than they could handle. They may step away from the exposure or react strongly enough to disrupt therapy. While strong initial reactions to EPR often diminish over time and predict better treatment outcomes, not all studies find this association to be true. For those who experienced intense distress with little to no symptom relief, exposure therapy may not seem like a helpful experience.
While therapeutic exposure can feel quite uncomfortable at times, there is no evidence that therapeutic exposure causes harm. A trusting relationship between individuals and therapists can minimize the short-term impact of these disruptions and setbacks, allowing for flexibility, experimentation, and commitment to the process.
The efficacy of ERP has been well established, with studies indicating that between one-third and half of individuals treated with ERP experience complete OCD symptom reduction, with many others achieving at least partial symptom relief. In adults, ERP was found more effective than serotonin reuptake inhibitor (SRI) antidepressants, an especially significant finding in light of the stark difference in symptom relief after treatment ends. 45%-89% of individuals taking SRIs experience recurring symptoms after discontinuing medication, and ERP shows ongoing symptom improvement after ERP concludes. ERP is versatile enough to provide effective symptom relief for populations in different settings or intensities, and with or without medication.
Despite broad research support, more research is needed to understand how to address individuals with inadequate responses. Studies show that some variance in treatment response may depend on symptom severity, insight, and co-occurring disorders such as severe depression. ERP can be challenging for both individuals and therapists, but positive treatment outcomes show that temporary discomfort during treatment can still lead to significant symptom improvement.
While many experience OCD symptom reduction with ERP, a recent research analysis concluded that the therapeutic effect of ERP requires more rigorous study to more accurately reflect its efficacy. With these challenges, the future of ERP likely includes a deeper examination of what makes ERP effective and the development of new approaches, such as identifying and utilizing genetic factors. ERP can also be effective when combined with Deep Transcranial Magnetic Stimulation (Deep TMS™), a noninvasive medical device treatment that safely regulates neural activity for OCD relief. Deep TMS has particularly been shown to offer relief to patients experiencing treatment-resistance, making the case for a combined treatment regimen that can bolster its overall efficacy.