Inference-based CBT for OCD

1. Introduction

Version followed: the 12-module inference-based therapy (IBT) programme in O'Connor & Aardema, Clinician's Handbook for Obsessive Compulsive Disorder: Inference-Based Therapy (Wiley; dated Dec 2011 by the publisher, often cited as 2012). It is used here as currently delivered through the official I-CBT client worksheets, exercise sheets, training cards and quizzes on icbt.online (2022–2023 uploads). "IBT" is the older name and "I-CBT" the current one. The earlier manual, O'Connor, Aardema & Pélissier (2005) Beyond Reasonable Doubt, is not drawn on. Its older "reasoning devices" terminology is given alongside the current "con artist tricks" in 4.19. [source: Wiley handbook page; icbt.online home and client-materials pages]

I-CBT is a cognitive therapy designed specifically for OCD. Its starting claim is that an obsession begins with an obsessional doubt (the primary inference, e.g. "maybe the door is unlocked"). That doubt is produced by a reasoning process called inferential confusion. Inferential confusion means mistaking an imagined possibility for a real probability: the person over-invests in remote possibilities and distrusts the senses, the self and common sense. Feared consequences (secondary inferences), anxiety and compulsions all follow downstream from the doubt. [source: Ferreira & Koszegi 2019; IOCDF guide; Aardema, "What is I-CBT?"]

How change happens: the client learns how the doubt is built, as a story assembled from facts, rules, hearsay, experience and "it's possible". They then learn that the doubt has no direct evidence in the here and now, so it is "100% imaginary" and "100% irrelevant". They find the exact point where they crossed from reality into imagination, and return to what the senses and common sense already show (reality sensing). Once the doubt loses credibility, compulsions and anxiety lose their reason to exist. There is no exposure, no deliberate provocation of fear and no debating of probabilities. As one I-CBT trainer puts it, "We are not trying to reason our way out of OCD"; the aim is to stop reasoning one's way into it. [source: Hosbrough overview slides; Aardema, "What is I-CBT?"; client worksheets 5–8]

2. Framework

Format. A typical course is 18–24 one-hour sessions, though this varies by client. The most common format is weekly individual sessions; group, intensive and videoconference formats also exist, and the self-help books can supplement therapy. Medication can continue alongside. One secondary review gives 12–20 sessions [uncertain: the counts differ between sources; the handbook's own count was not seen]. Treatment is delivered by licensed clinicians with I-CBT training. [source: IOCDF guide; Ferreira & Koszegi 2019]

Structure. The handbook organises treatment as a pre-treatment phase followed by three phases containing 12 modules, plus a trouble-shooting chapter. Each module comes with a client worksheet (teaching text), an exercise sheet (in-session and home exercises), a daily training or practice card, and a quiz. [source: Wiley handbook TOC; icbt.online client-materials page; client exercise sheets 1–12]

[source: Wiley handbook TOC; IOCDF guide; client worksheets 1–12]

Session pacing. With 18–24 sessions and 12 modules, roughly 1.5–2 sessions per module after 1–2 assessment sessions is a workable plan. Spend extra time on Modules 2–4 and 7–8, where most clients need repetition [synthesis].

Typical session shape [synthesis, built from the materials' structure]. (1) Review the previous training card and exercise sheet using the client's own examples. (2) Introduce the module's concept, using the worksheet and the client's material. (3) Do the in-session exercise together. (4) Give the quiz, or go through its questions verbally. (5) Assign the exercise sheet and the daily training card.

Criteria for moving on. The sources build some checkpoints into the materials:

• Module 6 self-assessment: "Do you see how your OCD can be resolved?" (yes/no), plus a 0–100% confidence rating.
• Module 9 practice card: 0–10 ratings of believing the OCD story is a fact, and of seeing it as "just a story".
• Module 12: if confidence in handling a slip is below 80%, repeat the relapse steps. If the client's estimated "% non-OCD" is below 80%, repeat the relevant modules.

[source: client exercise sheets 6, 9, 12]

Otherwise, use these working criteria [synthesis]:

• After Phase I: the client can name the primary doubt, its reasons, the story and the self-theme, and can map a live episode.
• After Phase II: the client can find the crossover point in real time, and has done reality sensing at least sometimes without rituals.
• End of Phase III: the doubt has near-zero credibility, compulsions are largely gone, and a written relapse plan exists.

The Module 12 sheet defines complete resolution as: the doubt gets zero credibility, produces no emotional or behavioural reaction, no longer drives thinking or planning, and the client uses the senses normally in former OCD situations. [source: client exercise sheet 12]

3. Guiding principles

1. Work upstream on the primary doubt. Target the doubt itself, not its consequences or the anxiety. Practically: when a client describes a feared catastrophe, trace it back to the first "maybe" and work there. [source: client worksheet 1; Aardema, "What is I-CBT?"]
2. Never argue the content. The training slides warn: "No arguing with the client's reasoning!" Practically: do not debate probabilities or offer counter-evidence about the feared outcome. Examine how the doubt was constructed instead. [source: Shroyer Module 3 slides; client worksheet 10]
3. The doubt is 100% imaginary. Obsessional doubt has no direct evidence in the present, from outside or from inner states. Practically: keep asking "what, right now, tells you this?" [source: client worksheet 5]
4. The doubt is 100% irrelevant. Something being possible does not make it relevant. Practically: compare the doubt with everyday possibilities the client ignores without effort, such as a meteor strike. [source: client worksheet 6]
5. Use normal doubt as the benchmark. Normal doubts arise from evidence, fit the context and resolve quickly. Practically: the client's own non-OCD reasoning is intact, so borrow it. Ask why they trust their eyes when crossing a road but not at the stove (selectivity). [source: client worksheets 5–6; Ferreira & Koszegi 2019]
6. Trust the senses and common sense. Certainty exists before the doubt arrives, and distrust of the senses or self is the "lifeblood" of OCD. Practically: look once, accept that it is enough, and act. [source: client worksheets 8, 10]
7. The obsession is a story, and changing the story changes the doubt. Practically: aim to cast reasonable doubt on the obsessional doubt, not to produce certainty. Brief relief counts as progress. [source: client worksheet 3; Shroyer Module 3 slides]
8. Ask, don't tell. Build the story and the insights collaboratively, through questions. Practically: draw the reasons out of the client ("What makes you doubt…?") rather than lecturing. [source: Shroyer Module 3 slides]
9. No exposure, no fear provocation, no testing. Anxiety becomes irrelevant once the doubt is seen as false. Practically: do not set up exposure hierarchies, and discourage "testing it out", which is itself a trick. [source: Aardema, "What is I-CBT?"; client worksheet 10]
10. No reassurance. Practically: answering "Is it safe?" feeds the doubt. Redirect to what the senses show, and to how the doubt was built. [source: Aardema, "What is I-CBT?"; client worksheet 12]
11. Compulsions cannot solve an imaginary problem. Rituals respond to a story, not to reality, and they generate more doubt. Practically: frame dropping rituals as the logical consequence of seeing the doubt for what it is, not as endurance. [source: client worksheets 1, 7]
12. The self is the context of the doubt. Doubts cluster where a feared possible self says the person is vulnerable. Practically: identify the feared self, then build the real self from actual actions, feelings, values and feedback from others. [source: client worksheets 4, 11]
13. Work with the client's own material. Every module reuses the client's own doubt, reasons and story. Practically: keep one running written "OCD story" and update it as new elements emerge. [source: client exercise sheets 3, 7]
14. Be brief and don't ruminate. Dismissing a doubt should take 1–2 minutes, and re-thinking it is another trick ("let's discuss it"). Practically: stop the client's in-session analysis loops once the trick has been named. [source: client exercise sheet 10]
15. The client becomes their own therapist. Slips are learning opportunities, not relapse. Practically: from Module 9 on, hand the analysis over to the client. [source: client worksheet 12; exercise sheet 12]

4. Intervention inventory

Exercises 4.2–4.21 follow the module order of the client exercise sheets and training cards on icbt.online, which are adapted from the O'Connor & Aardema handbook. All steps here are paraphrased. All example therapist language is my own illustrative wording unless it is quoted and cited. Give the client the official worksheet, exercise sheet and quiz for each module; they are free downloads. [source: icbt.online client exercise sheets 1–12 and worksheets 1–12]

4.1 Assessment and IBT evaluation tools (pre-treatment)

• Purpose / when: Sessions 1–2. Build rapport, give psychoeducation, assess symptoms and screen for inferential confusion. The results also give you baselines to track change against. [source: IOCDF guide]
• Steps:
  1. Take a standard OCD assessment, including a severity measure (e.g. Y-BOCS) [synthesis: standard practice, not specified in the sources].
  2. Administer the handbook's tools, each described here without reproducing items: the Inferential Confusion Questionnaire (ICQ-EV); the IBT clinical scales; a therapy evaluation form and scale; an avoidance and situational profile scale; and a diary. Fear-of-self measures exist in the I-CBT literature, but none are drawn on [uncertain].
  3. List every current obsession. For each, record the trigger situations, the doubt, the feared consequences, the compulsions (overt and mental) and the avoidance.
  4. Explain that treatment is about the reasoning that produces the doubt, not about exposure.
• Example language (illustrative): "We won't be asking you to face your fears to get used to the anxiety. We'll look closely at how the doubt gets started, because that's where OCD's power comes from."
• Watch for: You can only rate the conviction behind the doubt (insight) once you know what the doubt is. Contents and scoring of the ICQ-EV and the IBT scales were not seen; consult the handbook appendices. [source: Wiley handbook TOC, Ch. 2 and Appendices 1–5; uncertain on scale contents]

4.2 Mapping the obsessional sequence (Module 1)

• Purpose / when: First module. The client learns that OCD runs in a fixed order: trigger → doubt → feared consequences → anxiety → compulsion. They also learn that the doubt is the source and that compulsions include mental acts. [source: client worksheet 1, exercise sheet 1]
• Steps:
  1. Teach the parts using the worksheet. An obsession is a doubt ("what if", "might be", "could be"). Worries such as a burglary come downstream of the primary doubt ("the door might be unlocked").
  2. Practise on the sheet's worked case (David's driving anxiety). The client labels the trigger, doubt, anxiety and compulsion.
  3. The client completes a five-column form (prompt, doubt, consequence of the doubt, anxiety, compulsive action) for one or two current obsessions.
  4. They repeat the form for a past obsession that no longer bothers them.
  5. They repeat it again for an obsession another person might have that means nothing to them, to show that the structure is the same while the content is arbitrary.
• Example language (illustrative): "Before the fear of a fire, what was the very first 'maybe'? Let's write that one down. Everything after it depends on it."
• Watch for: Clients often name the consequence ("the house burns down") as the obsession. Keep moving them back until you reach the first "maybe". It is working when the client spontaneously separates the doubt from its consequences.

4.3 Creating doubt through doubting (Module 1 creative exercise)

• Purpose / when: Module 1. Shows the client from the inside that doubting multiplies doubt, rather than resolving it. [source: client exercise sheet 1]
• Steps:
  1. Choose an everyday action the client does without OCD, such as saying goodbye on the phone or switching off the TV.
  2. Have them keep asking whether they really did it, and did it properly.
  3. They rate whether doubt went up, down or stayed the same.
  4. Variant from the sheet: for feelings toward a loved one, rate certainty before and after rehearsing doubts.
• Example language (illustrative): "Ask yourself a few times whether you really said goodbye. What happens to your certainty as you keep asking?"
• Watch for: Keep this to non-OCD material and stop as soon as the point is made. The variant about feelings for a loved one can touch relationship-OCD themes, so choose with care [synthesis].

4.4 Training Card 1: live sequence mapping

• Purpose / when: Daily homework after Module 1. [source: client exercise sheet 1]
• Steps:
  1. Three times a day, while a compulsion is happening, map the sequence.
  2. Slow down and ask how much of the OCD would remain if the doubt were false.
  3. Do not debate the doubt.
• Example language (illustrative): "When you catch yourself checking, just note what the doubt was. You don't need to argue with it yet."
• Watch for: Mapping can turn into reviewing. Keep it to noting the steps.

4.5 Finding the reasons behind the doubt (Module 2)

• Purpose / when: Module 2. Doubts feel reasonable because they rest on reasoning, even when the client can't put it into words. Exposing that reasoning makes it the target of therapy. [source: client worksheet 2, exercise sheet 2]
• Steps:
  1. The client writes down the two doubts that bother them most and identifies the core doubt.
  2. For each doubt, they list two justifications in each of six categories: abstract facts; rules; hearsay; personal experience; "it's possible"; and other reasons.
  3. They write the reasons as they occur during the doubt, not as calm reflections afterwards.
  4. Model the task on the sheet's worked example of a metal-contamination doubt.
• Example language (illustrative): "When the doubt about the stove comes, what makes it feel worth taking seriously? Is it something you read, a rule you follow, something that happened to someone else, or simply that it's possible?"
• Watch for: Make clear that you are not judging the reasons as right or wrong yet; that comes later. It is working when the client can produce reasons for the doubt in real time.

4.6 Reasons behind another person's doubts (Module 2, Exercise 2)

• Purpose / when: Module 2. Shows from a distance how justification works on doubts the client doesn't share. [source: client exercise sheet 2]
• Steps:
  1. Use the six-category form for two doubts given on the sheet: going suddenly "crazy" and hitting someone, and broken glass in a child's meal.
  2. Compare these reasons with the client's own.
• Example language (illustrative): "These reasons sound convincing for someone else's doubt. How are they built differently from yours, if at all?"
• Watch for: A given doubt may overlap with the client's own theme. If so, swap in another neutral one [synthesis].

4.7 Training Card 2: "could be" restatement

• Purpose / when: Daily homework after Module 2. [source: client exercise sheet 2]
• Steps:
  1. At least four times a day, name the doubt behind a compulsion or a surge of anxiety.
  2. Restate it as "could be" or "might be".
  3. Identify the reasoning behind it. If none comes to mind, ask why the doubt feels real.
• Example language (illustrative): "Try saying it as 'my hands might be contaminated' rather than 'my hands are contaminated'."
• Watch for: Clients who state doubts as facts ("my hands are dirty") may have poorer insight. The restatement helps show where the inference is.

4.8 Writing the obsessional story (Module 3)

• Purpose / when: Module 3. The doubt feels real because a credible story with a past, present and future supports it, and stories can be changed. The written story becomes the client's master document for the rest of therapy. [source: client worksheet 3, exercise sheet 3; Shroyer Module 3 slides]
• Steps:
  1. Combine the doubt from Module 1 with the reasons from Module 2.
  2. Draw the story out by asking questions rather than telling ("What makes you doubt…?"), following up on each answer with "Why?"
  3. Build the story collaboratively. Make it persuasive: add vivid detail, link the parts smoothly with a beginning, middle and end, and write it in the first person.
  4. Identify its "weapons": facts, rules, hearsay, personal experience, possibility and storytelling.
  5. Read the two sample stories on the sheet (cutting out one's tongue; a stove left on). Note that each one is equally credible to its owner.
  6. Update the story whenever new elements emerge, including in Module 7.
• Example language (illustrative): "Let's write your doubt as the story OCD tells you, in your words and as convincingly as you can. Start with how it begins."
• Watch for: Make it clear that the story becomes "real" only when the client acts on it [source: Shroyer slides]. Some clients find writing the story distressing. Present it as studying how the story is built, not as exposure [synthesis].

4.9 Story-building exercises: new theme, pen story, mug card (Module 3)

• Purpose / when: Module 3. Shows that any doubt can be manufactured by storytelling, and that stories shift mood and perceived reality. [source: client exercise sheet 3; Shroyer Module 3 slides]
• Steps:
  1. New theme: the client picks one theme the sheet offers (park benches are contaminated; a letter may not have been mailed; people may misunderstand you on the phone). They list supporting reasons, weave them into a convincing story using storytelling devices, and compare it with their own story.
  2. Pen story: using the handbook exercise, the client writes a frightening story about an ordinary object, then a hopeful one.
  3. Training Card 3 (daily): invent positive and negative stories about everyday objects, such as a mug, and notice how one's attitude to the object changes. When a doubt appears, recall the story behind it.
• Example language (illustrative): "Notice how a few details made you a little uneasy about a park bench you've never worried about. That's the same machinery your OCD uses."
• Watch for: It is working when the client says something like "it's just a story too" about their own doubt.

4.10 Identifying the vulnerable self-theme (Module 4)

• Purpose / when: Module 4. Doubts arise only where a feared possible self (the "OCD self") says the person might go wrong. Naming that self explains why OCD is so selective. [source: client worksheet 4, exercise sheet 4]
• Steps:
  1. Model the process on the sheet's cases. With Joe, recentre each doubt on the self ("I am the sort of person who could…") and combine the doubts into one theme. With John, whose doubts centre on cleanliness and order, ask what he is not obsessed about and why; then read John's story about inheriting his father's traits.
  2. The client lists their own doubts and recentres each one on the self.
  3. They find the common theme and write down what they fear they could become.
  4. They write why they are convinced of this possible self.
  5. They compare that reasoning with the reasoning behind ordinary, everyday doubts.
  6. Helpful questions from the worksheet: what do the doubts share, what does the checking say about you, and what sort of person would do this? No daily card goes with this module.
• Example language (illustrative): "You check the lights, but you don't worry about where you parked. What kind of person does the OCD say you might be, that only these things need checking?"
• Watch for: Clients with harm, sexual or religious themes may feel shame. Present the feared self as a possibility OCD has constructed, not a hidden truth. It is working when the theme explains new doubts as they appear. [source for framing: client worksheet 4; caution: synthesis]

4.11 Selectivity questioning (used throughout)

• Purpose / when: From Module 4 on, and whenever a doubt seems compelling. The client's ordinary trust in the senses in other areas shows that the OCD doubt is selective. [source: Ferreira & Koszegi 2019; Hosbrough overview slides; client worksheet 6]
• Steps:
  1. Name a comparable situation where the client trusts their senses without effort, such as crossing a road after looking.
  2. Ask what makes this one different.
  3. Link the difference to the self-theme, not to any real evidence.
• Example language (illustrative): "You looked once for cars and crossed. Why is one look enough there but not at the front door?"
• Watch for: Ask with curiosity, not as a gotcha.

4.12 Normal versus obsessional doubt (Module 5)

• Purpose / when: Module 5. Normal doubts have direct evidence in the here and now and resolve quickly; obsessional doubts have no such evidence, from outside or from inner states. [source: client worksheet 5, exercise sheet 5]
• Steps:
  1. Compare normal doubts (rain tomorrow, how long a journey takes) with obsessional ones (did I turn off the stove; did I read that word correctly).
  2. Work through the sheet's four short stories: a cat escaping, a pharmacist recounting pills, a fear of hitting a passer-by, and ants in a wardrobe. For each, the client states the doubt, says whether it is obsessional, and explains specifically why.
  3. Point out that "imagination" here means anything not directly tied to present reality, including inner reality (e.g. no actual anger when doubting whether one might hit someone).
• Example language (illustrative): "What did you see, hear or feel, right then, that started the doubt? If nothing, where did it come from?"
• Watch for: The client will say "but it's possible". Acknowledge the possibility and move to Module 6. Don't argue it.

4.13 Checking one's own story for here-and-now links (Module 5, Exercise 2; Training Card 5)

• Purpose / when: Module 5 homework. Shows that the client's own story has no direct link to the present. [source: client exercise sheet 5]
• Steps:
  1. Go through the written OCD story line by line and look for anything directly linked to the present.
  2. Write down any links found, and note what is missing that would connect the doubt to the present.
  3. Training Card 5 (daily): for each obsessional doubt, ask whether any direct evidence supports it. Compare what the doubt says "could be" with what the senses, perception and common sense report.
• Example language (illustrative): "Which line of your story is something you actually observed at the time? Let's underline only those."
• Watch for: A "link" may turn out to be a memory or hearsay from another time or place. Mark it as such.

4.14 Possibility is not relevance (Module 6)

• Purpose / when: Module 6. Something being possible does not justify acting on it. Obsessions "thrive on possibility", but abstract possibility is different from possibility in the here and now. [source: client worksheet 6, exercise sheet 6]
• Steps:
  1. Use the worksheet's analogies. A meteor could land on your head, yet nobody watches the sky. A ceiling could fall, but only cracks or strange noises would justify concern.
  2. Exercise 1: the client lists two obsessions they find incredible (other people's), then recognises that their own are equally detached from evidence.
  3. Exercise 2: take a neutral situation (the sheet uses crossing a street) and pile on possibilities until it feels unsafe. Then identify what is wrong with the story: its irrelevance to the present, not the details of each possibility. Apply the same analysis to the client's own story.
  4. Self-assessment: does the client see how their OCD can be resolved (yes/no)? Confidence 0–100%. How do they think they can best resolve it?
  5. Training Card 6 (daily): for each doubt, check for direct evidence. Bring to mind an everyday possibility that the client would never act on because it is irrelevant, and use it to see the doubt as irrelevant without debating it.
• Example language (illustrative): "I'm not saying it's impossible. I'm saying 'possible' was never a good enough reason for you anywhere else. Why is it a reason here?"
• Watch for: Don't get pulled into estimating probabilities. That is the "let's discuss it" trick. A low confidence rating is a cue to revisit Modules 2–5 [synthesis].

4.15 Finding the crossover point: the OCD bubble (Module 7)

• Purpose / when: Module 7. Reality and imagination are separate worlds. The crossover point is the first thought that takes the client beyond their senses into the "OCD bubble", where it is hard to return; there is a choice point before the urge to ritualise. [source: client worksheet 7, exercise sheet 7; Hosbrough overview slides]
• Steps (four-step exercise, also Training Card 7):
  1. Identify the crossover thought: the first thought that went beyond the senses. Ask how it makes the senses seem irrelevant.
  2. Hold still on the bridge: hold off all rituals and avoidance for at least one minute while picturing standing on a bridge between the world of the senses and the world of imagination.
  3. Choose: move into the doubt or back toward the senses. If the client went in, ask whether anything was actually resolved and whether the doubt is gone for good. If they came back, ask what helped.
  4. Record the key thoughts that carried the client beyond reality, and add them to the OCD story.
  5. Explain why rituals backfire. They give brief relief but undermine security (repeatedly testing a door loosens it) and leave the person less certain, more stressed and mentally exhausted.
• Example language (illustrative): "Let's slow the tape down. You turned the key and felt it lock. What was the very next thought, the one that took you away from what you'd just felt?"
• Watch for: The first try usually finds a later thought; keep going back. Also point out that absorption in the bubble can make people miss real things around them. It is working when the client names the crossover point while it happens, not afterwards.

4.16 Reality sensing (Module 8)

• Purpose / when: Module 8, the core skill. Trusting the senses in the ordinary way gives enough certainty to dismiss the doubt. "Senses" include inner senses, such as noticing that there is no real intent to harm. [source: client worksheet 8, exercise sheet 8; IOCDF guide]
• Steps (practise several times a day; Training Card 8):
  1. When an obsession arises, hold still on the bridge between the two worlds.
  2. Look at what is there, once, without effort.
  3. Recognise that this information is enough. Seeking more means crossing into OCD.
  4. Notice the uncomfortable "void" left by not doing the ritual.
  5. Recognise that the void is imaginary, and feel the certainty the senses give.
  6. Act on what the senses show: dismiss the obsession and do no compulsion.
  7. Basic rules: use the senses as you would in any non-OCD situation; set a criterion for when a task is complete (finish showering, then leave; lock the door, then move on); stop when the senses and common sense say the task is done.
  8. Avoid: staring, looking hurriedly, and filling in with imagination what can't be seen clearly.
• Example language (illustrative): "Look at the switch the way you'd look at any light switch. What do you see? That's all the information there is. Anything beyond that is the story."
• Watch for: Reality sensing can turn into a new checking ritual (staring, looking again, "sensing harder"). One ordinary look is the rule. The feeling of "not doing enough" is expected and is not evidence. [source: client worksheet 8, exercise sheet 8]

4.17 Sorting valid from invalid justifications (Module 9, Exercise 1)

• Purpose / when: Module 9. Separates real caution (direct experience, relevant present evidence) from hearsay and invented stories. [source: client exercise sheet 9]
• Steps:
  1. Analyse the sheet's case of John and the door: all his reasons come from other times and places, not from what he observes now.
  2. Mark which statements actually justify doubt in the here and now.
  3. Repeat the analysis on the client's own story.
• Example language (illustrative): "Which of these reasons would make a non-OCD person go back and check? Let's keep only those."
• Watch for: The client may count past experience ("once I did leave it open") as present evidence. Name it as a past event from another context.

4.18 Building the alternative story (Module 9, Exercise 2; Practice Card 9)

• Purpose / when: Module 9. Replaces the obsessional story with a reality-based story built the same way, so it feels just as real. The aim is reasonable doubt about the OCD story, not certainty. [source: client exercise sheet 9; client worksheet 9; Shroyer Module 3 slides]
• Steps:
  1. Start from a direct sensory observation (e.g. the door is locked and the lock is reliable).
  2. Add rich, realistic detail from experience (e.g. the lock held through cold weather; it has never opened by itself).
  3. Add any further detail from experience and common sense.
  4. Note how the feeling about the doubt changes at each stage.
  5. Use the elements that make stories feel lived: rich detail, smooth flow, being part of the story, personal significance, and imagination.
  6. Practice Card 9 (daily): when an OCD story starts, trace it back to its beginning and replace each step with a point grounded in reality. Rehearse the alternative as a story. Rate 0–10 three statements: the OCD story is a fact; despite the exercises, the OCD story is still the most credible; the OCD story is just a story like any other.
• Example language (illustrative): "Tell me the non-OCD story of leaving the house this morning, starting with what you actually felt in your hand when you turned the key."
• Watch for: The alternative story must start from the senses, not from reassurance ("nothing bad will happen"). Brief easing of the doubt counts as progress. Clients who say they are "not good at stories" can still do it. [source: client worksheet 9; Shroyer Module 3 slides]

4.19 Spotting the OCD con artist's tricks (Module 10)

• Purpose / when: Module 10, plus ongoing self-management. OCD uses recognisable tricks to make a doubt seem connected to reality. The goal is to see how the doubt was built, not to argue whether it is probable. [source: client worksheet 10, exercise sheet 10]
• Steps:
  1. Teach the tricks (table below).
  2. The client writes out the OCD story sentence by sentence and labels each sentence with its main trick, then any secondary ones. The sheet models this with a contamination example.
  3. Training Card 10 (daily, 1–2 minutes): (a) identify the specific trick; (b) see how it makes the doubt false and irrelevant; (c) vividly imagine how the situation feels under the non-OCD story; (d) let the doubt go.
  4. If the client finds themselves going over the doubt again and again, that is another trick. If they still can't accept that a slightly possible doubt is irrelevant, take it up in session.
• Example language (illustrative): "Which trick is this one? Someone else's garage door being open, so maybe yours is — that's borrowing an event from somewhere else."
• Watch for: Labelling tricks can turn into analysing them at length. Keep the four steps brief. It is working when a doubt is labelled and dropped in under two minutes.

[source: client worksheet 10 for the tricks; Ferreira & Koszegi 2019 for the reasoning devices; the mapping between the two columns is my own synthesis]

4.20 Building the real self (Module 11)

• Purpose / when: Module 11. The feared OCD self is a mask. The real self is grounded in actual actions, feelings, values and feedback from others; building it reduces vulnerability to the self-theme. [source: client worksheet 11, exercise sheet 11]
• Steps (five exercises):
  1. Actions: list today's everyday actions, infer the qualities each one required, and combine them into a statement of who the client is.
  2. Real feelings: during activities, notice actual feelings and desires, separate them from what OCD says the client "might" feel, and compare.
  3. Autobiography: write about 500 words emphasising accomplishments. Then consider what it would actually take to become the feared self, and whether that is realistic.
  4. Others' views: ask several friends or a partner for specific qualities with examples, and compare these with the OCD self.
  5. Values and strengths: list values, goals and principles; strengths; what others thank the client for at home, at work and in relationships; roles; sources of pride; challenges overcome; and how the client sees themselves coping in future. Finish with a statement affirming the real, non-OCD self.
  6. Practice Card 11 (daily): after an activity or a compliment, ask what it says about the real self, and note where it contradicts the old OCD theme.
• Example language (illustrative): "You fear being careless. What did you actually do today, and what did each of those things take?"
• Watch for: Asking others for feedback can turn into reassurance-seeking if it targets the feared theme ("am I dangerous?"). Keep requests to general, specific qualities [synthesis]. Also watch for discounting positive feedback ("the OCD non-self"). [source: client worksheet 11]

4.21 Knowing and doing: moving on and relapse prevention (Module 12)

• Purpose / when: Final module. The client becomes their own therapist and treats slips as learning. [source: client worksheet 12, exercise sheet 12]
• Steps:
  1. Review progress: how much has improved, and which learning points helped most.
  2. Six-step prevention: (a) identify high-risk situations; (b) rehearse how each could unfold (trigger, doubt, emotion, ritual); (c) rehearse stopping before crossing into imagination; (d) label the doubt obsessional and therefore invalid; (e) note which situations touch the self-theme; (f) ask three questions: Does it reflect my theme? Is it a doubt? Do I feel the old OCD sensation? If all three are yes, dismiss it.
  3. If a slip happens: don't panic, because a slip is not a relapse. Retrace where the client crossed over. Note their state of mind then (stress, preoccupation, insecurity, fatigue) and why OCD caught hold. Prepare for next time by staying aware of the trigger, rehearsing resistance and a non-OCD response until it feels mastered. Rate confidence 0–100% and repeat if below 80%.
  4. Remove leftover safety behaviours: watching for OCD; checking whether it is there; keeping it "on the back burner"; avoiding thoughts or topics; subtle mental avoidance; reassurance-seeking; quick rituals; rituals condensed into words or movements; subtle testing.
  5. Know the risk states for slips: loss of focus (giving the doubt credibility, or putting it off), fatigue, excitement (e.g. holidays) and stress that activates the self-theme.
  6. Practice Card 12 (ongoing): anticipate stressors, plan for stressful events, keep using the exercises, fill the space OCD leaves with non-OCD activities that reflect the real self, and estimate the "% non-OCD". Below 80%, repeat the relevant modules.
• Example language (illustrative): "Picture the next time you're exhausted after a long shift and the doubt shows up at the door. Walk me through exactly where you'd stop."
• Watch for: Expect some emotional reactions to linger, and catch OCD early. [source: exercise sheet 12]

4.22 Module quizzes

• Purpose / when: End of each module. Checks that the client has understood the concepts before moving on. [source: icbt.online client-materials page; quiz answer sheet in the handbook]
• Steps: Give the module's quiz in session or as homework, go over wrong answers, and re-teach those concepts with the client's own material.
• Example language (illustrative): "Let's look at the two you weren't sure about. They're the heart of this module."
• Watch for: Getting the quiz right isn't the same as applying it. Check application on the client's own doubts [synthesis].

5. Handling problems

The handbook has a dedicated trouble-shooting chapter (Ch. 15), plus sections on common client queries and therapist queries. Those are not drawn on [uncertain]. Guidance below is tagged as either drawn from the client materials and training slides, or as my own [synthesis].

"But it's still possible." This is the most common sticking point.

• Agree that it is possible, and decline to argue about probability.
• Move to irrelevance (4.14): possible is not the same as relevant here and now. Compare with the possibilities the client ignores every day.
• If it recurs, name it as the "maybe this time" or "maybe later" trick.
• If the client still can't accept it, the exercise sheet says to take it up in session, so revisit Modules 5–6 with fresh examples from their own life. [source: client worksheets 6, 10; exercise sheet 10]

Client keeps debating the doubt in session, or the therapist gets drawn into it.

• The slides are explicit: "No arguing with the client's reasoning!"
• Name the "let's discuss it" trick, and steer back to how the doubt was built and where the crossover happened.
• If you notice you are offering counter-evidence about the feared outcome, stop and ask the client what their senses showed. [source: Shroyer Module 3 slides; client worksheet 10]

Partial or fluctuating conviction.

• Brief relief, or a reply like "I guess that could be true", means the module is working. You are aiming for reasonable doubt about the obsessional doubt, not certainty.
• Track change with the 0–10 ratings on Practice Card 9 rather than waiting for full belief. [source: Shroyer Module 3 slides; exercise sheet 9]

Discomfort or a "void" when the client stops rituals.

• Tell the client in advance that feeling they are "not doing enough" is expected and is not evidence.
• In reality sensing, the void is something to notice and recognise as imaginary, not something to fill. [source: client worksheet 8, exercise sheet 8]

Stuck: the client can't find reasons, a story or the crossover point.

• If no reasons come, the training card's fallback is to ask why the doubt feels real [source: exercise sheet 2].
• Use the third-person exercises (other people's doubts, a neutral situation turned obsessional), since many clients can see the mechanism there before they can see it in themselves [source: exercise sheets 1, 2, 6].
• Slow the episode down frame by frame in session, starting from the last moment the client was clearly in contact with their senses [synthesis].
• Clients who say they're "not good at stories" can still do the work [source: client worksheet 9].

Symptoms that seem driven by a "not just right" feeling rather than a doubt.

• Look for the implied doubt behind the feeling (e.g. "maybe it isn't done properly", "maybe something will happen"), and follow the usual sequence.
• IOCDF reports that I-CBT has been used for ordering and arranging symptoms, but the pages give no specific procedure for incompleteness [uncertain; synthesis].

Poor insight or overvalued ideas.

• The secondary sources describe I-CBT as particularly suited to clients with strong conviction or poor insight [source: Ferreira & Koszegi 2019; IOCDF guide].
• Practically: don't challenge the conclusion. Stay with the process (the reasons, the story, the crossover point, the selectivity) and with the client's own normal reasoning in other areas, where conviction is not at stake [synthesis].

Overwhelm. Writing or rehearsing the OCD story, or self-theme work, can stir distress or shame. [synthesis throughout]

• Pace by spending more time on third-person examples before moving to the client's own material.
• Keep the story-writing focused on how it is built rather than on graphic detail.
• End sessions with brief reality sensing on neutral objects in the room.
• Present the feared self as a construction of OCD, not a revelation.
• I-CBT is not designed to provoke anxiety. If sessions are routinely highly distressing, the method is being misapplied.

Non-adherence with homework. [synthesis throughout]

• Find out whether the card felt too long, too abstract, or too much like a ritual.
• Cut the load down to one doubt and one card, and practise the card live in session (e.g. stand at the clinic door and do reality sensing).
• Link homework to existing routines, and review it first thing every session so it clearly matters.
• Where the training cards specify a frequency (three or four times a day; several times a day for reality sensing), start lower and build up.

I-CBT tools turned into rituals.

• Watch for re-looking or staring during reality sensing, repeating "it's irrelevant" or "that's a trick" as a mantra, rituals condensed into words or movements, subtle testing, or "keeping OCD on the back burner" [source: exercise sheet 8; client worksheet 12].
• Response: name it as a safety behaviour or ritual and go back to the rule of one ordinary look, then act. Ask whether the phrase is being used to get a feeling of certainty, which is a ritual, or to move on, which is the skill [synthesis].

Reassurance-seeking, from the therapist, family, or through the Module 11 feedback exercise.

• Don't answer the content. Redirect to what the client's own senses showed and where the crossover happened [source: Aardema, "What is I-CBT?" (no reassurance); client worksheet 12].
• For Module 11, help the client ask for general qualities, not verdicts on the feared theme [synthesis].
• Work with family members to stop answering reassurance questions, and to point the client toward what they can see or hear [synthesis; family accommodation is not addressed in the sources].

Ruptures. [synthesis throughout]

• Clients can hear "100% imaginary" as "your suffering isn't real" or "you're being silly". Make the distinction explicit: the distress and the compulsions are real; it is the doubt that lacks a basis in the present.
• If a rupture happens, own any lecturing tone and go back to collaborative questioning. The slides' "ask, don't tell" stance is the main protection against ruptures [source for stance: Shroyer Module 3 slides].
• Clients who have had ERP may see I-CBT as "avoiding exposure". Explain that they will still go into their usual situations, but now relying on their senses rather than testing their fear [source: Aardema, "What is I-CBT?"; framing: synthesis].

Distinguishing real risk from obsessional doubt.

• By the model's own definition, a doubt prompted by direct present evidence (a smell of gas, a visible crack, an actual feeling of anger or intent) is a normal doubt and should be acted on [source: client worksheets 5–6].
• Where there is a genuine history of violence, current intent, child-safeguarding concerns or suicidal ideation, do a standard risk assessment and follow the usual safeguarding procedures. Don't use I-CBT language to dismiss real risk, and don't let it stand in for proper assessment of harm-themed obsessions [synthesis].
• Assess comorbid depression and suicide risk with standard tools throughout treatment [synthesis].

Slips and relapse after treatment.

• Expect slips at times of fatigue, excitement (e.g. holidays), lost focus, and stress that triggers the self-theme.
• Use the Module 12 plan: retrace the crossover, identify the state of mind at the time, rehearse, and re-rate confidence (below 80% means repeat).
• Repeat earlier modules if the client's "% non-OCD" estimate falls below 80%. [source: client worksheet 12, exercise sheet 12]

Population limits.

• I-CBT depends on telling imagination apart from reality, so it may not suit younger children; child adaptations are case-level only.
• IOCDF describes it as usually second-line, after first-line treatments have failed or when a client is reluctant to try them.
• Treat comorbid conditions within the treatment plan. [source: IOCDF guide]

Sources

Sources:

• Inference-based Cognitive Behavioral Therapy (I-CBT) — IOCDF OCD Treatment Guide
• icbt.online — official I-CBT site (home)
• Client work and exercise sheets — icbt.online
• Client Exercise Sheets 1–12 — icbt.online
• Client Worksheets 1–12 — icbt.online
• Client Worksheet 10: Tricks of the OCD Con Artist — icbt.online
• What is I-CBT? — icbt.online (F. Aardema)
• Overview of I-CBT Treatment (M. Hosbrough; adapted from O'Connor & Aardema) — icbt.online
• I-CBT Fridays, Module 3: The Obsessional Story (B. Shroyer; adapted from O'Connor & Aardema) — icbt.online
• Clinician's Handbook for Obsessive Compulsive Disorder: Inference-Based Therapy — Wiley product page and table of contents
• Ferreira, T. & Koszegi, N. (2019). Obsessive-Compulsive Disorder According to the Inference-Based Approach. PsiLogos 17(1–2)

Further reading (not drawn on): Inference Based Cognitive Behavioral Therapy — Psychotherapy and Psychosomatics (Karger).

Books:

• O'Connor, K. & Aardema, F. (2011/2012). Clinician's Handbook for Obsessive Compulsive Disorder: Inference-Based Therapy. Wiley-Blackwell. Only the table of contents and adaptations are drawn on; the full text is not.
• O'Connor, K., Aardema, F. & Pélissier, M.-C. (2005). Beyond Reasonable Doubt: Reasoning Processes in Obsessive-Compulsive Disorder and Related Disorders. Wiley. Not drawn on [uncertain].
• Resolving OCD (two-volume I-CBT self-help guide, listed on icbt.online). Not drawn on; authors and year not verified [uncertain].