This article is for informational purposes only and does not constitute clinical advice, diagnosis, or a substitute for individual assessment by a qualified professional.

Quick summary

• An ERP exposure hierarchy is a personalised, ranked list of the situations, thoughts, and sensations your OCD pushes you to avoid, ordered from least to most distressing.
• You build it in three stages — Map, Match, Move — and you rate each item using a simple 0–100 distress scale (SUDS).
• The aim of each exposure is not to “wait until the anxiety drops” but to test whether your feared prediction actually comes true; this expectancy-violation reframe is one of the biggest shifts in modern ERP (Craske et al., 2014).
• Self-directed ERP can be reasonable for milder OCD, but there are clear situations where it is not — and knowing the difference matters.
• A free, clinician-built worksheet and a “should I do this alone?” decision aid are included below.

What you won’t find elsewhere

Most hierarchy guides hand you a blank ladder and a 0–10 scale and leave you to it. This one gives you my Map → Match → Move method (the framework I actually use in sessions), a decision aid for whether self-directed ERP is sensible right now, and an honest account of the mistake I see most often — built around current expectancy-violation research rather than the older “feel the fear until it fades” model. There’s a downloadable worksheet at the end.

How to Build Your Own ERP Exposure Hierarchy

Over the past decade of treating obsessive-compulsive disorder, I’ve watched the same small moment happen again and again: a client opens a worksheet they downloaded the night before, looks at the empty rows, and has no idea what to actually write. Building your own ERP exposure hierarchy is one of the most useful things you can do between sessions — and one of the easiest to get subtly wrong on your own.

So let me give you a straight answer first. An ERP exposure hierarchy is a personalised, ranked list of the situations, thoughts, images, and sensations your OCD tells you to avoid, ordered from least to most distressing, so you can face them in a planned, gradual way. ERP stands for exposure and response prevention — deliberately approaching what you fear (exposure) while choosing not to perform the compulsion or ritual that normally brings relief (response prevention). Built well, the hierarchy turns a vague, all-day sense of dread into a clear, workable plan. Below, I’ll walk you through exactly how I build one with clients, and — just as importantly — how to judge whether doing this without a therapist is a good idea for you at the moment.

What is an ERP exposure hierarchy, in plain terms?

An ERP exposure hierarchy is your fear, broken into steps you can climb. Each step is a specific thing you currently avoid or neutralise, paired with a number that captures how distressing it feels.

ERP is the exposure-based form of cognitive behavioural therapy that the National Institute for Health and Care Excellence recommends as a first-line psychological treatment for OCD (National Institute for Health and Care Excellence, 2005). The hierarchy is its backbone. Edna Foa and colleagues, whose treatment manual is the standard clinical reference for ERP, describe assessment and the construction of an ordered list of feared situations as the groundwork on which the whole protocol is built (Foa et al., 2012). The reason for the ranking matters: OCD doesn’t usually present as a single giant fear. It presents as dozens of small avoidances and rituals stacked on top of each other. Ranking them lets you start somewhere achievable and build evidence as you go.

A quick word on what a hierarchy is not. It is not a to-do list you complete once and bin. And it is not a fixed staircase you must climb in perfect order. I’ll come back to that, because the staircase image causes more stalls than almost anything else.

Is it safe to build an ERP hierarchy on your own?

Self-directed ERP can be reasonable if your OCD is on the milder end and you’re broadly safe and stable; it is not appropriate when your symptoms are severe, when risk is involved, or when other conditions are in the mix. This is the honest, clinically grounded answer, and it’s the one most templates skip.

NICE describes OCD treatment as stepped care: lower-intensity options, including guided self-help and brief CBT with ERP, are offered first when functional impairment is mild, while more intensive therapist-led CBT is recommended as impairment increases (National Institute for Health and Care Excellence, 2005). In other words, working through a hierarchy largely on your own sits at the lower rungs of that system by design. It was never meant to carry the heaviest cases alone.

Here’s the decision aid I’d want you to run through honestly before starting.

Self-directed ERP may be reasonable if:

• Your OCD is mild to moderate, and you can still get through most of your day.
• You feel safe, and you’re not having thoughts of harming yourself or anyone else.
• Your obsessions don’t centre on themes where a misjudged exposure could cause real harm (for example, certain harm, contamination with genuine risk, or relationship themes that involve other people).
• You have some support around you and a way to access professional help if things escalate.

Pause and seek professional input first if:

• Your rituals take up hours a day, or you’ve largely stopped leaving the house, working, or eating normally.
• You’re experiencing thoughts of suicide or self-harm, or any urge to harm others.
• You’re pregnant, postnatal, or managing another significant mental or physical health condition alongside OCD.
• Your OCD theme makes “designing your own exposure” genuinely risky — when in doubt, treat that as a yes.

If you’re in the second group, that’s not a failure, and it’s not a permanent verdict. It simply means a trained clinician should help shape the plan. What I often tell clients is this: the skill of ERP is not bravery, it’s judgement about what to expose yourself to and when — and that judgement is exactly what a therapist is for.

How to build your ERP hierarchy step by step: Map → Match → Move

You build an ERP hierarchy in three stages: Map what OCD is doing, Match each situation to a distress rating and the underlying fear, and Move through the steps in a way that tests your predictions. This is the method I use in the room, and it works on paper too.

Step 1 — Map

Start by mapping the territory, not by ranking anything. For one week, simply notice and write down three things: the obsessions (the intrusive thoughts, images, urges, or doubts that hook you), the compulsions (what you do to feel better — washing, checking, reassurance-seeking, mental reviewing, counting, confessing), and the avoidances (the places, objects, people, or topics you’ve quietly stopped going near).

Most people are surprised by how much land is in that third column. Avoidance is the part of OCD that hides in plain sight, because it doesn’t feel like a symptom — it feels like a sensible choice. Mapping it is what makes the rest possible.

Step 2 — Match

Now match each item to two things: a distress rating and the specific fear it triggers.

For the rating, use the SUDS — the Subjective Units of Distress Scale, a 0–100 self-rating where 0 is complete calm, and 100 is the most distress you can imagine. The SUDS was developed by Joseph Wolpe and has anchored exposure-based therapy ever since (Wolpe, 1969). You can use 0–10 if you prefer, but I find 0–100 gives you finer gradations, which matters when you’re trying to find a genuine “starting” rung. Rate how distressing it would feel to face each situation while not doing the compulsion — that second half is the whole point.

The part templates miss is the matching to the fear. Touching a door handle isn’t the exposure; the exposure is touching the handle and sitting with the belief that you’ll now spread illness, and it will be your fault. Pin down the feared prediction for each item, in your own words. You’ll need it for the next step.

When you’ve rated everything, order the list from lowest SUDS to highest. That ranked list is your ERP exposure hierarchy.

An example ERP hierarchy (contamination theme)

Here’s a simplified example of what the result might look like for someone with a contamination fear. Yours will be entirely your own.

Step 3 — Move

Now you move — but how you move is where modern ERP departs from the old script. The traditional instruction was to stay in an exposure until your anxiety roughly halved, on the theory that you were waiting for it to “habituate.” Current evidence reframes this. Michelle Craske and colleagues argue that the active ingredient is expectancy violation: the learning that happens when your feared prediction fails to come true, regardless of whether your anxiety drops in that particular session (Craske et al., 2014).

That changes the question you ask. Instead of “Has my anxiety gone down yet?”, you ask, “What did I predict would happen, and what actually happened?” You pick an item — and it doesn’t have to be the very lowest one; pick something that’s a real stretch but still doable — name your prediction out loud, do the exposure, prevent the response, and afterwards check the prediction against reality. The NHS describes the same broad approach for OCD: facing feared situations without neutralising them, generally starting with less anxiety-provoking steps before building up (National Health Service, 2023).

A few response-prevention examples to make it concrete. If your compulsion is washing, the response you prevent is the wash. If it’s checking the door, you leave it after one lock. If it’s seeking reassurance, you don’t ask, “Are you sure I didn’t do something wrong?” and you don’t Google it. If it’s mental reviewing, you let the doubt sit unanswered. Preventing the response is the half that does the work; exposure without it is just stress.

The mistake almost everyone makes

The single most common error in self-directed ERP is treating the hierarchy as a fixed staircase you must climb one perfect step at a time. This is one of the most misunderstood aspects of OCD work, and even experienced clinicians can slip into it.

Here’s what actually happens. People get stuck on a “low” item — say, a 30 — repeating it for weeks, waiting to feel nothing before they’ll allow themselves to move up. But OCD is slippery. It will let you do the 30 forever while quietly insisting the 40 is different, special, the real one. Meanwhile, your distress at the 30 never fully vanishes, because you’ve turned the exposure itself into a kind of reassurance ritual: “See, I did it, and nothing happened, I’m fine, I’m fine.”

The reframe is this: the hierarchy is a living map, not a contract. You can revisit, reorder, and skip around. You’re not waiting for a feeling to disappear; you’re collecting evidence that you can handle uncertainty and that your predictions are unreliable. Vary the situations, do exposures in different places, and resist the urge to make each one “safe” before you start. Variability and the absence of safety crutches are precisely what strengthen the new learning (Craske et al., 2014). If an item feels too big, you don’t necessarily need a smaller version of the same fear — sometimes you need the same item with one more safety behaviour removed.

Frequently asked questions

How long does it take to build an ERP hierarchy? The mapping week is the real work. Once you’ve genuinely noticed your obsessions, compulsions, and avoidances, ranking them takes an afternoon. Don’t rush the noticing — a hierarchy built from a hurried list tends to miss the avoidances, which are usually where the most useful exposures hide.

What if all my items feel like a 90 or 100? That’s a common and important signal. It often means the fear hasn’t been broken into specific enough pieces, or that the OCD is severe enough that self-directed work isn’t the right tool right now. Try splitting items into smaller, more concrete situations; if everything still sits at the top, that’s a strong reason to involve a therapist rather than push on alone.

Do I have to start with the lowest item? No. Starting low can be a gentle way in, but you’re not obliged to climb in strict order. Pick something that’s a genuine stretch yet doable, and choose based on what will teach you the most — not simply on the smallest number.

Is doing ERP at home as effective as seeing a therapist? Guided self-help and brief, ERP-based CBT are recommended first-line options for milder OCD within NICE’s stepped-care model, with more intensive therapist-led treatment recommended as impairment increases (National Institute for Health and Care Excellence, 2005). Meta-analytic evidence shows large effect sizes for CBT in OCD overall (Olatunji et al., 2013). The honest answer: home-based ERP can help meaningfully for milder presentations, but it isn’t a substitute for therapy when OCD is severe, or risk is involved.

What’s the difference between a fear hierarchy and an ERP hierarchy? They’re closely related. A “fear hierarchy” is the general idea of ranking feared situations by the distress they evoke, which dates back to early behaviour therapy. An ERP hierarchy is that ranked list built specifically for exposure and response prevention — so each item names not just the situation but the compulsion you’ll resist and the prediction you’re testing.

When to seek professional help

Please reach out for professional support if your OCD is taking up large parts of your day, if it’s stopping you from working, studying, eating, or leaving home, or if self-directed work leaves you feeling worse rather than steadier. And if you’re ever having thoughts of harming yourself or others, treat that as a reason to get help now, not later.

Good first steps in the UK: speak to your GP, who can refer you or signpost local services; in England, you can also refer yourself directly to an NHS Talking Therapies service without going through your GP (National Health Service, 2023). To find an accredited therapist, the British Association for Behavioural & Cognitive Psychotherapies (BABCP) keeps a public register via its CBT Register UK. The charity OCD-UK offers information, support, and details of specialist NHS OCD services.

If you are in crisis in the UK, you can call Samaritans free on 116 123, at any time.

About the author

Federico Ferrarese is a BABCP-accredited Cognitive Behavioural Psychotherapist and BPS Chartered Psychologist with an MSc in Applied Neuroscience, specialising in the treatment of OCD using CBT and Exposure and Response Prevention. He runs an online practice offering therapy in English and Italian to clients across the UK and internationally.

BABCP accreditation number: 00001005090 Read more about Federico →

References:
Craske, M. G., Treanor, M., Conway, C. C., Zbozinek, T., & Vervliet, B. (2014). Maximizing exposure therapy: An inhibitory learning approach. Behaviour Research and Therapy, 58, 10–23. https://doi.org/10.1016/j.brat.2014.04.006
Foa, E. B., Yadin, E., & Lichner, T. K. (2012). Exposure and response (ritual) prevention for obsessive-compulsive disorder: Therapist guide (2nd ed.). Oxford University Press.
National Health Service. (2023, April 4). Overview — Obsessive compulsive disorder (OCD). https://www.nhs.uk/mental-health/conditions/obsessive-compulsive-disorder-ocd/overview/
National Institute for Health and Care Excellence. (2005). Obsessive-compulsive disorder and body dysmorphic disorder: Treatment (NICE guideline No. CG31). https://www.nice.org.uk/guidance/cg31
Olatunji, B. O., Davis, M. L., Powers, M. B., & Smits, J. A. J. (2013). Cognitive-behavioral therapy for obsessive-compulsive disorder: A meta-analysis of treatment outcome and moderators. Journal of Psychiatric Research, 47(1), 33–41. https://doi.org/10.1016/j.jpsychires.2012.08.020
Wolpe, J. (1969). The practice of behavior therapy. Pergamon Press.