Context: I wrote this as my final paper in writing class this past semester. The assignment was to choose a topic related to the professional field you are pursuing. Since my long-term goal is to become a therapist specializing in OCD treatment (among other conditions), I chose to write about OCD pathology and treatment methods. What follows is an exploration of what OCD is, how it is learned, how it is treated, and new developments in explaining and optimizing the effectiveness of Exposure and Response Prevention (ERP).


This paper discusses the most accepted theories and treatment modalities for Obsessive-Compulsive Disorder (OCD). It begins with a comprehensive definition of OCD and the relevant background information needed to understand its pathology and treatment. Available treatments for OCD are described; the two most common, Exposure and Response Prevention (ERP) and Selective Serotonin Reuptake Inhibitors (SSRIs), are discussed in detail. Special attention is given to the role of Master’s-level therapists and the potential value of my personal experiences when I enter this field. Next, classical conditioning and negative reinforcement are presented as mechanisms for OCD acquisition to be addressed during treatment. The most common theory used to explain the success of ERP, Emotional Processing Theory (EPT), is explored with a focus on the natural process of habituation during ERP trials (“exposures”). Finally, new research presents an alternative model that focuses on extinction learning in ERP: Inhibitory Learning Theory (ILT, “inhibitory learning”). The potential ways this new research may be used to strengthen long-term outcomes of ERP treatment are examined.

Obsessive-Compulsive Disorder (OCD) is a chronic mental health condition characterized by the presence of obsessions and compulsions. It is very common, with a yearly prevalence rate of about 1.2% among adult Americans (Harvard Medical School, 2007). According to the National Institute of Mental Health (2019), “obsessions are repeated thoughts, urges, or mental images that cause anxiety.” They are typically experienced as intrusive, unwanted, and difficult to control. While everyone experiences occasional unwanted thoughts or preoccupations at some point in their lives, OCD obsessions are excessive and usually cause significant interference with a person’s daily activities and values (American Psychiatric Association, 2013, p. 238). OCD sufferers frequently feel compelled to reduce the distress or anxiety caused by obsessions with a compulsion, a repetitive, ritualistic behavior or mental action (National Institute of Mental Health [NIMH], 2019). After performing a compulsion, the individual may feel like they have neutralized or avoided the threat posed by the obsession. However, this relief is only temporary, and continuing to yield to obsessions increases their intensity over time. While most people with OCD are aware that compulsions are irrational and ultimately unhelpful, they are extremely difficult to control without learning an alternative way to cope.

This is why my future role as an OCD therapist is important. Qualified counselors, therapists, social workers, clinical psychologists, and/or psychiatrists working in an outpatient office setting are the first line of treatment for OCD. In more severe cases, inpatient or longer-term residential treatment may also become necessary (International OCD Foundation, n.d.-b). I hope to gain experience by working as a residential counselor or mental health technician, an undergraduate level position, until I complete my master’s degree and required training. Then, I will be able to provide psychotherapy to clients one-on-one in either an inpatient or outpatient setting. If I eventually pursue a doctorate in clinical psychology, I could have the additional capability to make formal diagnoses. While only a medical doctor, such as a psychiatrist, can prescribe medications and perform medical treatments, psychotherapy is where the hard work and learning of OCD treatment is done.

Currently available therapies for OCD include Acceptance and Commitment Therapy (ACT), mindfulness, occupational therapy, Cognitive-Behavioral Therapy (CBT), and specific forms of CBT called Dialectical Behavioral Therapy (DBT) and Exposure and Response Prevention (ERP). These are typically used in conjunction with medications that affect the levels of various neurotransmitters in the brain. According to psychiatrist Christina LaRosa, MD, “there are unfortunately no notable lifestyle habits or supplements that have been scientifically proven to treat or improve symptoms of OCD (personal communication, January 5, 2020). I have personal experience with many these treatments, which will be an asset as I transition from the role of OCD treatment client to OCD treatment provider.

Selective Serotonin Reuptake Inhibitors (SSRIs) are the most prescribed medications for depression, anxiety, and OCD. They work by preventing the reabsorption, or reuptake, of the neurotransmitter serotonin into the presynaptic neurons of the brain. This allows serotonin to stay in the synaptic gap for longer and continue to stimulate receptors in the postsynaptic neuron (Licht, Hull, & Ballantyne, 2017, p. 601). LaRosa explains that while treatment with SSRIs alone may be enough to reduce symptoms in patients with mild OCD, they are most effective when combined with CBT and ERP:

The mainstay of treatment for moderate to severe OCD remains combination treatment with an SSRI (selective serotonin [re]uptake inhibitor) and effectively delivered Cognitive Behavioral Therapy with Exposure Response Prevention (CBT with ERP). Mild OCD may respond to either of those interventions alone, but research has consistently shown that combination treatment is much more beneficial . . . Effectively delivered CBT with ERP by a well-trained therapist in combination with a properly dosed SSRI (higher doses tend to work better) is definitely the most effective treatment (personal communication, January 5, 2020).

Cognitive Behavioral Therapy is based on the idea that our thoughts, behaviors, and emotions are all interconnected. While we cannot directly control our automatic thoughts, feelings, and physical sensations, we can always change our behaviors. Over time, engaging in healthy behaviors will start to have a positive effect on our thoughts and emotions. “You might go to a therapist to and ask to have your [distressing] thoughts and feeling removed. That doesn’t work. A good CBT therapist will show you how to move the behavior so that the thoughts and feelings naturally gravitate in that direction (Hershfield & Corboy, 2013, p. 44). However, there are some thoughts we do have control over. In the CBT model, rumination, mental actions, and distorted thinking are all considered controllable, albeit with much effort and difficultly. The cognitive aspect of CBT is focused on challenging these thought distortions with logical reasoning. Unfortunately, this has its limitations, since disorders such as OCD are not rational. No matter how much someone may try to reason with OCD thoughts, they will still feel extremely dangerous, urgent, and even life-threatening.

The behavioral aspect of CBT is where ERP comes into play. This is a specific form of CBT that focuses on changing how the person responds to the obsession:

Exposure and Response Prevention (ERP) involves systematic, repeated, and prolonged exposure to situations that provoke obsessional fear, along with abstinence from compulsive behaviors. In short, you purposely get in front of your fears, either in literal, physical terms (for example, touching something that upsets you) or in theoretical terms (for example, imagining a feared situation), and you practice resisting the compulsive response (Hershfield & Corboy, 2013, p. 44).

To fully comprehend ERP, one must first understand the conditioning, or learning, that led to the development of the obsessions and compulsions in the first place. For example, someone with harm OCD may have a disturbing intrusive thought (a form of obsession) about running someone over with their car. To make sure this didn’t happen, they may check their mirrors to make sure someone isn’t lying in the road behind them. This reduces their anxiety so they can continue driving toward their destination. Every time the intrusive thought appears, the driver does the same thing, checking and then trying to return to driving. The problem is that by doing this repeatedly, they are learning that the only way to “escape” the anxiety is to perform the checking compulsion. This is called negative reinforcement, a form of operant conditioning. Over time, the urge to perform the checking behavior will become increasing frequent and difficult to resist.

In this scenario, the driver is not biologically inclined to experience fear when a random thought about running over someone pops into their mind. Rather, it is a conditioned emotional response. Occasional intrusive thoughts are actually very common in people with or without OCD, but they don’t usually bother most people. The problem is that with OCD, these thoughts “trigger extreme anxiety that gets in the way of day-to-day functioning” (International OCD Foundation, n.d.-c). This is because people with OCD are more likely to take their thoughts seriously and view even the slightest disturbance as a threat (Geller et al., 2017). They become fixated on “what-ifs” and worst-case scenarios that other people hardly ever think about. The excessive focus leads to a false association between an otherwise neutral thought and a frightening outcome. In the same way, external stimuli can also become associated with fearful events through classical conditioning. For instance, the hypothetical driver with harm OCD might learn to associate hitting a bump in the road with the fear of running someone over. Hitting a bump acts as an external “trigger” for the fearful thought (“Was that a pedestrian?”), and the driver feels compelled to do the checking compulsion.

Theoretically, the goal of ERP is to cause the extinction of both the conditioned emotional response (the fear caused by the obsession) and the negatively reinforced compulsive response. In the example with the driver, this means that hitting a bump or experiencing an intrusive thought would neither cause anxiety nor result in compulsion. To accomplish this, an ERP therapist might begin by identifying major obsessional triggers and organizing them by the intensity of the fear they evoke. Beginning with the lower-intensity triggers first, the therapist would then assign specific tasks designed to maximize and prolong exposure to the feared triggers. This is the “exposure” element of ERP (International OCD Foundation, n.d.-a). During each of these “trials,” the client must also be prevented from performing the compulsion to reduce the anxiety. This “response prevention” element of ERP requires the client to actively resist the compulsive urge, but this can be made easier if there is a way to bring awareness to, discourage, or make the compulsion more difficult. For the driver with OCD, a possible exposure could be driving a mile and purposefully hitting as many bumps as possible. A passenger might observe and count the number of times the driver checks their mirrors, with the goal being to reduce that number to zero. In theory, the driver would gradually find it easier to resist the compulsion, and their anxiety about the obsessions would begin to decrease and eventually be eliminated.

However, even when someone with OCD is treated with ERP, it is unlikely that the intrusive thoughts and obsessions will completely disappear. “When I meet a new client,” psychotherapist Jennifer Thomblison explains, “their goal is often to make their uncomfortable thoughts ‘go away,’ but this is not usually a realistic goal given the nature of the disorder. Generally, the overall goal of OCD treatment is a reduction in obsessions and compulsions and an improvement in daily functioning” (personal communication, January 6, 2020). LaRosa further suggests that some cases of OCD can be “treatment-resistant,” meaning they are very difficult to treat even with intensive ERP and SSRIs. In these cases, other medications and augmentative therapies may be used to improve symptom tolerance:

Overall, the goal of treatment in any case of OCD is complete remission of symptoms, meaning that any obsessions or compulsions remit entirely. If complete remittance is unable to be achieved with effective treatment (which would be an indication of treatment-resistance), then we strive for better overall tolerance of the symptoms (ie the thoughts might still be there, but are less bothersome and easier to ignore), and may also try alternative medications for augmentation of the SSRIs. Broadly speaking, a successful outcome in OCD is one in which the patient’s day-to-day function is no longer affected by their obsessions or compulsions (personal communication, January 5, 2020).

I have experienced for myself how difficult it can be to find relief from treatment-resistant OCD. The improvement I have experienced with traditional ERP and SSRI treatment is significant, but it has not been enough to prevent my OCD symptoms from affecting my daily functioning. Thankfully, there is recent research that promises to change the way we view ERP and how it reduces obsessions and compulsions. OCD therapists hope to incorporate these new insights into ERP treatment to improve its efficacy.

For several decades, the primary evidence that ERP was working was the observation of a basic form of learning called habituation. When an organism is occasionally exposed to a stimulus, it will produce a response. If the organism is exposed to a stimulus many times, the intensity of the response will begin to decrease with repeated exposure (Licht, Hull, & Ballantyne, 2017, p. 191). In ERP treatment, this means that if someone is repeatedly exposure to an obsessional trigger, their resultant anxiety will naturally become less and less with each exposure. This process is non-associative, meaning that it does not require the formation of any new subconscious or conscious connections between a stimulus and a response. Instead, the fearful associations developed through negative reinforcement and classical conditioning simply “disappear” after repeated exposure to the triggering thoughts or stimuli. The model of learning that involves habituation is called Emotional Processing Theory:

Emotional processing theory (EPT) has traditionally been the dominant model for explaining improvement during ERP . . . This theory proposes that therapeutic exposure must activate a “fear structure” that is contained in memory, and then provide information that is incompatible with the fear structure. This incompatible information is thought to become integrated via “corrective learning,” such that non-fear based elements replace, or compete with, fear based associations. Fear reduction during exposure (i.e., habituation) is considered a critical index of change in ERP and evidence that learning is taking place. Habituation is a short-term sensory effect resulting in one’s decreased response to repeated stimulation such that one’s original reaction towards the stimulus diminishes in intensity or even disappears. Thus, patients who experience habituation are expected to respond less fearfully to anxiety-related stimuli over time (Abramowitz & Jacoby, 2016, p. 30).

In other words, an exposure must trigger a conditioned fear response, then provide alternative information to replace the faulty association. The evidence that this is working is the reduction of fear in response to the trigger (habituation). Of course, this only happens if the patient also resists the compulsive response (response prevention), preventing any negative reinforcement.

In traditional, habituation-based ERP, therapists are trained to look for evidence that anxiety is decreasing during and in between exposure trials, and that the person experiences less fear when beginning the next trial. There are three possible ways habituation can be observed: verbal (self-report of anxiety level at each stage of the exposure), behavioral (observable escape and avoidance behaviors, i.e. compulsions), and physiological (heart rate and skin conductance; Abramowitz & Jacoby, 2016, p. 30). The two most important are verbal and behavioral, since it is not generally necessary or practical to measure a person’s physiological response during ERP unless it is for research purposes.

However, recent research on ERP suggests that habituation may not always be a reliable indicator of treatment progress:

For one thing, many people who do ERP experience habituation of anxiety during and between sessions, and yet do not improve; or they have a good response to ERP at first, but then relapse at some point later on. In addition, some peoples’ OCD symptoms improve with ERP in the absence of habituation. All of this means that, although habituation is common during ERP (indeed, habituation is a natural process), it is not as straightforward as we once thought (Abramowitz, 2018).

Apparently, habituation can occur without an improvement in OCD symptoms, and OCD symptoms can improve without habituation. This may be because habituation is primarily an indicator of short-term learning, not retention. Little is known about the relevance of habituation to longer-term treatment success.

In fact, too much focus on habituation might actually hinder treatment. According to Abramowitz and Jacoby (2016), emphasizing the importance of anxiety going down during ERP can help foster an unhelpful perception of fear:

Emphasizing the importance of fear reduction during ERP, for example, implies that anxiety itself is inherently bad, and that treatment is only successful if one is anxiety-free. This may perpetuate a “fear of fear” mindset and lead patients to interpret inevitable (and normal) unexpected surges of fear (either within or outside of exposure trials) as signs of failure. Individuals with OCD might also use exposures to control their anxiety (i.e., “I know I can do this exposure because my anxiety will come down”), which is contrary to the aim of confronting and learning to tolerate anxiety and fear as normal and nonthreatening experiences (p. 30).

Indeed, anxiety is a common and harmless experience, and understanding this fact is key to OCD treatment. People with OCD tend to exaggerate the negative consequences of their anxiety; they have learned to avoid fear and fear-inducing experiences. Therefore, ERP tasks should be constructed to help people with OCD learn to tolerate their anxiety, not to eliminate it. Habituation can be thought of more like a pleasant “side effect” and not a requirement for success (p. 38).

Abramowitz and Jacoby suggest that the primary learning mechanism in exposure therapy is not habituation, but extinction. This is the reverse of conditioning, when the trigger (e.g. hitting a bump in the road) is presented so many times without the feared event (e.g. actually running someone over) that the person no longer expects the feared outcome to occur. While these two processes are related, and habituation has been suggested to contribute to extinction, there is a difference. With habituation, the person’s anxious response to the trigger naturally decreases with repeated exposure. With extinction, anxiety reduction is not necessary; the key is learning that the trigger is not actually harmful. The person no longer feels the need to do the compulsion, because they have learned that their fear does not pose a threat (p. 31-30). The new model developed to explain extinction in ERP is called Inhibitory Learning Theory. According to this model, the conditioning does not “disappear” after repeated exposure like Emotional Processing Theory suggests. Instead, the person learns a new association between the conditioned stimulus and something bad not happening. These two learned associations compete with each other, which explains why obsessions may return long after someone completes OCD treatment. For ERP to be effective, the non-fearful associations must become stronger than the fearful ones (p. 31). As Abramowitz (2018) explains, the goal of ERP from the inhibitory learning perspective is therefore to strengthen these “safe” associations:

ERP does not cause an obsessional fear to be “unlearned” or “erased.” Instead, ERP teaches new information about safety so that following successful exposure, a feared stimulus has both its original fear-based meaning (“door knobs are dangerous”) as well as the new safety meaning (“door knobs are generally safe”). In order to be optimally effective, ERP needs to help people learn safety in such a way that it is strong enough to block out (or inhibit) the original fear — and this is where the term inhibitory learning gets its name.

Exposure and Response Prevention is most effective when exposures are optimized for inhibitory learning. Therefore, this theory does not merely provide a better explanation for the learning mechanisms underlying ERP; it has the potential to fundamentally change the way both therapists and clients approach OCD treatment.

Inhibitory Learning Theory outlines a few novel strategies therapists can use to maximize the efficacy of ERP. The most important of these are an emphasis on anxiety tolerance as opposed to habituation and disconfirming the client’s fearful expectations. Exposures should be designed to “teach” people with OCD that intrusive thoughts and the anxiety they create are not harmful, and they can be tolerated without doing a compulsion:

The aim of ERP is to provide the person with new knowledge that (a) obsessional fears are less probable or severe than predicted, (b) anxiety and obsessional thoughts themselves are safe and tolerable, and (c) compulsive rituals are not necessary for safety or to tolerate anxiety (Abramowitz, 2018).

Of course, most people with OCD are already aware of these principles intellectually. The challenge is to “accept them [emotionally] and allow them to guide behavior” (Jennifer Thomblison, personal communication, January 6, 2020). A properly designed exposure trial should provide the evidence the mind needs to accept these facts on a subconscious, emotional level. This means that when someone with OCD faces a trigger in an exposure trial, they should be able to see that the feared outcome did not actually happen. If the feared outcome is in the distant future (e.g. going to hell for blaspheming God), the focus should be on whether the uncertainty about it was manageable or not (Abramowitz, 2018). By doing this, the person’s fearful expectations are violated, and a new association is made between fear trigger (e.g. saying “I love Satan”) and outcome (successfully tolerating uncertainty about going to hell). This effect is enhanced if the outcome “surprises” the client, in a pleasant way. In other words, exposure trials should trigger the most fear possible with the least objective chance that a negative outcome will occur. Moreover, the more challenging and effortful ERP is in the moment, the greater the potential for long-term learning (Abramowitz, 2018).

Exposures are also more effective when multiple fear triggers are combined. For example, someone with sexual harm OCD may have intrusive thoughts about molesting a child. A possible exposure for them could be to either imagine molesting a child (imaginal exposure) or to give an actual child a hug (“in vivo,” or real-life exposure). To maximize inhibitory learning, these exposures would be done separately at first, then simultaneously in one trial (i.e. imagining molesting a child while giving them a hug). Additionally, “optimal fear extinction also requires that safety learning occur in a variety of contexts. This is because if safety is learned in one situation, it may not necessarily be remembered in a different situation” (Abramowitz, 2018). This means a driver with harm OCD could learn to tolerate the anxiety caused by hitting bumps on I-75, but not on Main Street. Similarly, someone might learn to conquer their fears in the safety of their therapist’s office, but not at home. This is because the memory retrieval cues in the environment where extinction occurred are not present in the new environment. Therefore, the same ERP trial should be repeated in as many different environments and contexts as possible.

The research into inhibitory learning is still in its infancy, so additional studies are needed to determine if this approach is more effective in the long term than the traditional habituation model. However, the insights produced by Abramowitz and others are already being applied to OCD treatment. Many therapists who treat OCD, such as Thomblison, accept both theories as valid ways of explaining ERP:

One [theory] says that people eventually get used to the discomfort that the obsession creates when they don’t engage in the compulsion. A second theory suggests that by repeatedly not engaging in the compulsion, people begin to learn that usually nothing bad happens, and if it does it’s not linked to the compulsion itself (personal communication, January 6, 2020).

As an OCD therapist, I will be responsible for helping my clients get the most out of ERP. This new way of framing Exposure and Response Prevention will be an asset as I show them my clients how to overcome their obsessions. In fact, inhibitory learning principles have already been useful in my own treatment as an OCD patient, filling in the gaps where habituation was not possible. In the not-so-distant future, I hope to use the same new strategies that have helped me become more successful in ERP to empower others on their journey to OCD recovery.


Abramowitz, J. S. (2018). The inhibitory learning approach to exposure and response prevention. Retrieved from

Abramowitz, J. S. & Jacoby, R. J. (2016). Inhibitory learning approaches to exposure therapy: A critical review and translation to obsessive-compulsive disorder. Clinical Psychology Review, 49, 28-40.

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC: Author.

Clark, D. A. & Radomsky, A. S. (2014). Introduction: A global perspective on unwanted intrusive thoughts. Journal of Obsessive-Compulsive and Related Disorders, 3(3), 265-268.

Geller, D. A., McGuire, J. F., Orr, S. P., Pine, D. S., Britton, J. C., Small, B. J., . . . Storch, E. A. (2017). Fear conditioning and extinction in pediatric obsessive-compulsive disorder. Annals of clinical psychiatry: official journal of the American Academy of Clinical Psychiatrists, 29(1), 17–26.

Harvard Medical School. (2007). National comorbidity survey (NCSSC). Retrieved from Data Table 1: Lifetime prevalence DSM-IV/WMH-CIDI disorders by sex and cohort.

Hershfield, J. & Corboy, T. (2013). The mindfulness workbook for OCD: a guide to overcoming obsessions and compulsions using mindfulness and Cognitive Behavioral Therapy. Oakland, CA: New Harbinger Publications.

International OCD Foundation. (n.d.-a). Exposure and Response Prevention (ERP). Retrieved from

International OCD Foundation. (n.d.-b). How is OCD treated? Retrieved from

International OCD Foundation. (n.d.-c). What is OCD? Retrieved from

Licht, D. M., Hull, M. G., & Ballantyne, C. (2017). Psychology (2nd ed.). New York, NY: Worth Publishers.

National Institute of Mental Health. (2017). Obsessive-compulsive disorder (OCD). Retrieved from

National Institute of Mental Health. (2019). Obsessive-compulsive disorder. Retrieved from

Leave a Reply

Your email address will not be published. Required fields are marked *