When ERP Doesn’t Work: What the Research Really Says
ERP is the gold standard. But it’s not a magic bullet.
If you’ve explored treatment for OCD, chances are you’ve heard of Exposure and Response Prevention (ERP). It’s widely recommended by mental health professionals, backed by decades of research, and listed in international clinical guidelines as the frontline therapy for OCD.
And the truth is—it helps a lot of people. But not everyone.
For all its evidence base, ERP is also a treatment that many people struggle to engage with. Some never start. Others drop out. And many complete therapy but feel like they haven’t made the progress they hoped for.
This isn’t talked about enough.
In this post, we’ll take a closer look at what the research really says about the limits of ERP—why it’s so effective for some, and why others find it overwhelming, inaccessible, or incomplete.
What the Numbers Tell Us
Although ERP is widely recognised as an effective treatment for OCD, research shows that around 50% of individuals do not experience significant improvement, while 25–30% drop out of therapy before completing it, and a further 25–30% refuse to begin treatment at all (Abramowitz et al., 2018; Öst et al., 2015; Farris et al., 2013).
That’s not a small minority. That’s nearly half of all people who begin—or consider—ERP.
So why is this happening?
What Makes ERP So Challenging?
Researchers have explored several reasons why people find ERP difficult to start, stick with, or benefit from. These include both individual-level and systemic factors.
1. ERP Is Intentionally Confronting
ERP asks clients to face their fears, on purpose—and to resist the urge to make things feel “safe.” While this is the very reason it works, it also means the process can be emotionally intense.
Qualitative research has shown that clients often find ERP daunting and anxiety-provoking, especially in the early stages (Marsden et al., 2018; Lee & Rees, 2011). Without the right support, this emotional intensity can become a barrier rather than a bridge—leaving some people feeling too overwhelmed to continue.
2. The Rationale Often Doesn’t Land
One of the most consistent themes in research is that when clients don’t understand why they’re doing ERP, they’re far less likely to stick with it.
A recent review concluded that agreement with the ERP rationale—and clarity around how it works—was strongly associated with greater engagement and homework completion (Wheaton & Chen, 2021). Similarly, Leeuwerik et al. (2023) found that therapy felt more credible when the rationale was clearly communicated and made sense on a personal level.
3. ERP Can Feel Too Rigid or Impersonal
Some clients describe ERP as overly structured, limiting their ability to express themselves emotionally (Marsden et al., 2018). Others have reported that therapy materials weren’t personalised to their unique fears—especially when mental compulsions or abstract obsessions were involved (Leeuwerik et al., 2023).
If the therapy feels generic or mismatched, it’s no surprise that clients disengage.
4. Therapist Factors Matter—A Lot
Not all ERP is delivered well. Research shows that therapist behaviours such as offering reassurance, encouraging distraction, or focusing only on surface-level symptoms can dilute the effectiveness of treatment—and erode trust (Gillihan et al., 2012).
Clients are more likely to stay engaged when they feel seen, understood, and supported—not just instructed.
5. Mental Compulsions Are Often Missed
ERP is often associated with visible rituals like handwashing or checking. But many people with OCD perform mental compulsions—repeating phrases, neutralising thoughts, mentally reviewing conversations.
These are harder to spot, and if a therapist doesn’t recognise them, they can go unaddressed or even be accidentally reinforced (Gillihan et al., 2012).
6. Life Outside Therapy Can Get in the Way
Co-occurring conditions like depression or trauma symptoms, caregiving responsibilities, financial pressures, or lack of family support can all interfere with ERP (Millar et al., 2020; Bevan et al., 2010).
Even when someone is motivated, real-world stressors can make it hard to follow through with exposures or access consistent support.
What This Means for Therapy
None of this means ERP isn’t effective.
But it does mean we need to move away from a one-size-fits-all approach. The research increasingly supports the idea that ERP works best when it’s:
Clearly explained and collaboratively planned
Personalised to the person’s symptoms, values, and context
Delivered by therapists with specialist training in OCD and ERP
Supported by a strong, trusting therapeutic relationship
Final Thoughts: You’re Not Failing—The Model Might Be
If you’ve found ERP difficult, overwhelming, or just not helpful—it doesn’t mean you’re beyond help. And it certainly doesn’t mean you didn’t try hard enough.
It may simply mean the therapy didn’t fit your life, your needs, or your version of OCD.
In future posts, I’ll be exploring how these challenges show up in real-world stories, and what we can learn by listening more closely to the people who’ve lived it.
References
Abramowitz, J. S., Blakey, S. M., Reuman, L., & Buchholz, J. L. (2018). New Directions in the Cognitive-Behavioral Treatment of OCD: Theory, Research, and Practice. Behavior therapy, 49(3), 311–322. https://doi.org/10.1016/j.beth.2017.09.002
Bevan, A., Oldfield, V. B., & Salkovskis, P. M. (2010). A qualitative study of the acceptability of an intensive format for the delivery of cognitive-behavioural therapy for obsessive-compulsive disorder. The British journal of clinical psychology, 49(Pt 2), 173–191. https://doi.org/10.1348/014466509X447055
Farris, S. G., McLean, C. P., Van Meter, P. E., Simpson, H. B., & Foa, E. B. (2013). Treatment response, symptom remission, and wellness in obsessive-compulsive disorder. The Journal of clinical psychiatry, 74(7), 685–690. https://doi.org/10.4088/JCP.12m07789
Gillihan, S. J., Williams, M. T., Malcoun, E., Yadin, E., & Foa, E. B. (2012). Common pitfalls in exposure and response prevention (EX/RP) for OCD. Journal of obsessive-compulsive and related disorders, 1(4), 251–257. https://doi.org/10.1016/j.jocrd.2012.05.002
Lee, Y. H., & Rees, C. S. (2011). Is exposure and response prevention treatment for obsessive–compulsive disorder as aversive as we think? Clinical Psychologist, 15(1), 17–21. https://doi.org/10.1111/j.1742-9552.2011.00001.x
Leeuwerik, T., Caradonna, G., Cavanagh, K., Forrester, E., Jones, A.‐M., Lea, L., Rosten, C., & Strauss, C. (2023). A thematic analysis of barriers and facilitators to participant engagement in group exposure and response prevention therapy for obsessive–compulsive disorder. Psychology and Psychotherapy: Theory, Research and Practice, 96(1), 129–147. https://doi.org/10.1111/papt.12430
Marsden, Z., Teahan, A., Lovell, K., Blore, D., & Delgadillo, J. (2018). Patients' experiences of cognitive behavioural therapy and eye movement desensitisation and reprocessing as treatments for obsessive‐compulsive disorder. Counselling & Psychotherapy Research, 18(3), 251–261. https://doi.org/10.1002/capr.12159
Millar, J. F. A., Halligan, S. L., Gregory, J., & Salkovskis, P. M. (2020). When cognitive behavioural therapy for obsessive compulsive disorder fails: Service user perspectives [Unpublished doctoral thesis]. University of Bath.
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, 40, 156–169. https://doi.org/10.1016/j.cpr.2015.06.003
Wheaton, M. G., & Chen, S. R. (2021). Homework completion in treating obsessive–compulsive disorder with exposure and ritual prevention: A review of the empirical literature. Cognitive Therapy and Research, 45(2), 236–249. https://doi.org/10.1007/s10608-020-10125-0
