What is Inference Based CBT for OCD?

Inference-Based CBT (I-CBT) has been gaining attention and we've noticed it in new inquiries. More clients are arriving at MPC having already researched I-CBT online, and many are asking whether we offer it. It's not hard to see why it's generating interest: one of I-CBT's central claims is that it's possible to reduce OCD symptoms without deliberate exposure. For anyone who feels aprehensive about Exposure and Response Prevention (ERP), or who have had a bad experience with ERP, this is welcome news! So what is I-CBT, and how does it work? Let's take a closer look.

What is inference based CBT (I-CBT)?

I-CBT was developed in the late 1990s by respected OCD researchers Kieron O'Connor and Frederick Aardema, and it approaches OCD from a fundamentally different angle to traditional treatment. Where as traditional ERP focuses on what happens after an obsession arises, I-CBT is interested to target the reasoning that created the obsessional doubt in the first place.

The core idea is that obsessions are not simply intrusive thoughts that have been misinterpreted as significant. I-CBT sees that obsessions are a specific kind of doubt that relies on an imagined possibility (what could happen) as opposed to what reliable evidence (e.g., what the person can actually see, hear, and sense). This process is called inferential confusion whereby the person gives weight to possible "what if" scenarios as though this imagined threat were real.

For example, if we consider the thought "my hands might be contaminated", most people resolve this thought by relying on actual evidence: their hands look clean enough, there is no dirt remaining, and they remember using soap and washing for 1-minute. People can access this sort of reliable evidence are more able to move on.

In contrast, for someone with OCD there is excessive reliance on unreliable information (e.g., it doesn't feel the right amount of clean!) and the imagined possibility of being contaminated feels credible than what their senses are actually telling them.

The central aim in I-CBT works to reverse this and to help people to learn to trust their own perception and make decisions based on reliable information, rather than chasing a doubt that was never grounded in reality to begin with.

Key elements of the inference based CBT (I-CBT) model include:

• Identifying the internal narrative that makes obsessional doubt feel plausible

• Distinguishing between doubts grounded in observable reality and reliable evidence rather than those generated by imagination

• Understanding the personal themes that drive obsessional content (more on this later - this was the focus of my PhD!)

• Rebuilding trust in one's own senses and experience

  
  

What might inference based CBT (I-CBT) look like in the treatment room?

At surface level, one of the most distinctive things about I-CBT in practice is how different it can feel from a traditional ERP session.* Sessions are conversational and collaborative and there is no exposure hierarchy or deliberate confrontation with feared situations! You can see why this would be so appealing!!

*It's worth pausing here to distinguish between traditional and contemporary ERP. Older depictions of ERP that are still being circulated online can give the impression of a highly structured, clinician-directed process focused almost exclusively on exposure tasks. Contemporary ERP, as practised by experienced OCD clinicians, looks quite different. It is collaborative, relational, and makes significant room for understanding the meaning and narrative behind a person's OCD; not just the behaviours that maintain it. In practice, experienced clinicians working with OCD rarely draw from a single model. A well-stocked clinical toolkit might include a whole range of approaches (e.g., ERP, I-CBT, Cognitive Behavioural Therapy, Acceptance and Committment Therapy, EMDR, schema, Compassion Focussed Therapy... the list goes on!).

The skill lies not in applying any one of these rigidly, but in collaborating with a client to select the elements that are appropriate to their specific situation. Treatment becomes a genuine collaboration: therapist and client working together to understand the person's particular experience of OCD and to build an approach that is responsive to it. What works for one person in terms of model, pacing, emphasis, and therapeutic style may look quite different from what works for another, even when the diagnosis is the same.

I-CBT sits naturally within this broader toolkit. For some clients it will be the primary framework; for others it will be woven into treatment alongside other approaches. What it offers, distinctively, is a way into OCD that begins not with confronting feared situations but with examining the reasoning that makes those situations feel threatening in the first place.

An I-CBT session might might start by examining a recent obsessional fixation. I find that clients will quickly go into the whole story of the obsession, and I will draw their attention back to the origin of the obsession; "When that very first doubt came up, what was actually in front of you? What were your senses telling you? What happened in your mind to go to that next step? " From there, therapist and client work together to trace the reasoning that carried the person from observable reality into the obsessional narrative, we examine how the "what if" took hold, and what internal logic made it feel so real and credible.

This means that a significant part of the work involves identifying and unpacking the OCD narrative: the chain of reasoning that sustains the OCD story. Usually this will highlight themes of self-distrust, fear of being a bad person and an inflated sense of personal responsibility. Once we can help our clients to see that the narrative is an OCD construction, rather than an accurate reflection of reality, the OCD story starts to lose its power.

Between sessions, clients might be asked to practise noticing moments of inferential confusion in daily life. We train our clients to become skilled detectives at identifying the points at which their thinking shifts from the real and actual, to the imagined and possible. We practice refocusing our attention back to our senses rather than following the doubt that OCD wants you to be drawn into. This between-session practice is where much of the consolidation happens.

At this point, you can see that exposure has not been part of the process! However, in truth, engaging seriously in I-CBT still does involve a level of discomfort. While I-CBT does not use structured exposure in the traditional ERP sense, the work does strongly promote that people make choices in their live according to reality (and not the OCD story felt sense). This means not avoiding things and not doing compulsions and this is not an easy process.

I say to all my clients at some point, there is no way but through". It does takes real courage and effort but the therapist role is in helping you to want to do this.

Who might inference based CBT (I-CBT) suit?

I-CBT is not a replacement for ERP and in practice it is often used as an adjunct treatment skill to help engagement with ERP. ERP also remains the most established first-line treatment for OCD and should be considered carefully as part of any treatment plan.

However, I-CBT may be worth exploring for people who:

• Have not responded adequately to ERP or who have had poor experiences of ERP

• Find the deliberate anxiety provocation involved in ERP too distressing to sustain

• Have strong conviction in their obsessions (high overvalued ideation)

• Want to understand the cognitive roots of their OCD, not just manage its symptoms

• Have previously found exposure-based approaches helpful but want to address the underlying reasoning patterns

In practice, I find that my clients who have OCD are people who are big thinkers and the idea of a therapy that allows us to examine the thinking processes appeals to their natural interest in logic and reasoning. For this reason, it is I-CBT tends to be something I introduce to many of my clients.

What the Research Says about inference based CBT (I-CBT) for OCD

Inference-Based CBT (I-CBT) has accumulated a meaningful evidence base since its development in the late 1990s by respected OCD researchers Kieron O'Connor and Frederick Aardema. Research shows that I-CBT produces significant reductions in OCD symptom severity, and was easier to complete than traditional CBT for OCD.

Where I-CBT appears particularly promising is with OCD presentations that have historically been harder to treat than with ERP alone. These include people with overvalued ideation - where the feared outcome feels genuinely likely rather than recognised as an OCD thought. The reasoning-focused approach of I-CBT may be a better fit than exposure-based methods.

What the research doesn't yet tell us

The honest picture is that I-CBT remains an emerging model. It has fewer studies behind it than decades of ERP research, and whether it is fully non-inferior to CBT across all presentations and outcome measures has not yet been conclusively established. These are important caveats not to dismiss I-CBT (I rate it and I use it all the time!), but it is important to consider it as a well-supported and increasingly validated option rather than a proven replacement for first-line ERP.

A note on finding the right treatment

OCD can be so simple and yet so complex. The best ffective treatment is always one that fits the individual; their presentation, their current capacity, their values, and what they have already tried. I-CBT represents an important development in the OCD treatment landscape precisely because it offers a different entry point for people who need one.

If you're unsure whether I-CBT, ERP, or another approach might be most useful for you or someone you care about, speaking with a psychologist who specialises in OCD is the best place to start. A good OCD therapist will be familiar with the range of evidence-based options and can help you think through what is most likely to help.

The team at Melbourne Psychology & Counselling includes psychologists with special interest in OCD and its treatment. You can learn more about our approach or get in touch via our OCD information page or contact us directly.