This programme is a treatment manual written for mental health professionals. It assumes clinical training, the ability to make a diagnosis, and access to supervision. It replaces neither your clinical judgement nor your professional responsibility. The diagnostic criteria here are reformulated in our own words and never reproduced: consult the original manuals for the letter of the text.
1. The programme at a glance
Indication. Obsessive-compulsive disorder in adults, all presentations: contamination, checking, taboo obsessions, symmetry and incompleteness, obsessions with no visible compulsion.
Reference model. Exposure with response prevention, in its cognitive form: Salkovskis's model (1985, 1999) and Rachman's work (1997, 1998) on inflated responsibility and thought-action fusion, combined with the exposure protocol of Foa and Kozak. NICE (2005) recommends this approach as a first-line treatment.
Format. Sixteen individual sessions of 90 minutes, weekly, over roughly four months, followed by two booster sessions at one month and three months. That volume amounts to twenty-four therapist hours, above the ten-hour threshold NICE sets for moderate to severe disorder. Sessions 4 to 12 involve an exposure conducted in session and cannot be shortened.
Target mechanism. Not the disappearance of obsessive thoughts, but change in three things: what the patient believes their thoughts mean, what they do to defend against them, and their tolerance of doubt.
| Session |
Focus |
What the session produces |
| 1 |
Assessment, Y-BOCS, inventory |
List of obsessions and rituals |
| 2 |
Individual formulation |
Vicious-circle diagram, written with the patient |
| 3 |
Hierarchy and hunt for hidden rituals |
Exposure hierarchy, list of mental rituals |
| 4 |
First exposure with response prevention |
Anxiety curve recorded, ritual not performed |
| 5 |
Exposure and inflated responsibility |
Responsibility apportioned, in writing |
| 6 |
Exposure and thought-action fusion |
Non-occurrence experiment |
| 7 |
Imaginal exposure |
Recording of the feared scenario |
| 8 |
Mental rituals |
Inventory, and one mental ritual dropped |
| 9 |
Reassurance and the family |
Written agreement with a family member |
| 10 |
Incompleteness and "just right" |
Exposure to imperfection, sustained |
| 11 |
Taboo obsessions |
Exposure to the content, without neutralising |
| 12 |
Generalisation and variation |
Exposure in a new context |
| 13 |
Residual rituals and discreet avoidance |
Final inventory |
| 14 |
Tolerating doubt, giving up control |
Experiment in relinquishing |
| 15 |
Consolidation |
A full week without rituals |
| 16 |
Personal plan, relapse prevention |
Summary sheet written by the patient |
What the patient takes away. Seven printable worksheets, listed in section 33 and downloadable from this page: inventory of obsessions and rituals, exposure hierarchy, exposure record, mental-ritual diary, agreement with the family, record of reassurance-seeking, personal plan.
What sets this programme apart from plain exposure. The patient does not expose themselves in order to habituate, but in order to discover that their prediction is false and that the ritual was not what prevented the catastrophe. That difference is not cosmetic: it changes what you record, what you say during the exposure, and what counts as success. An exposure in which the patient held out for two hours while silently reciting a prayer is not an exposure, it is a longer ritual.
2. Before you start
Who this programme is for
This text is addressed to psychologists, psychiatrists, psychotherapists and mental health nurses trained in cognitive behavioural therapy. It assumes that you can conduct a diagnostic interview, recognise suicide risk, and tell an obsession from a delusional idea.
It is not written for patients. The text contains exposure scenarios written without softening, guidance on what must not be said, and blunt descriptions of obsessive content. Handed to someone affected, it would serve as obsessional material.
What this programme is not
It is not a treatment for hoarding disorder. Since DSM-5, hoarding has been a separate diagnosis, and its treatment differs appreciably: the hierarchy, the targets and the work with the family do not transfer.
It is not a treatment for OCD in children. Parental involvement is central there and the protocol is different.
It is not an intensive protocol. The fifteen-session-in-three-weeks formats described by Foa and Kozak achieve excellent results and remain an option where they are available. The weekly format described here is the one actually practised in ordinary settings.
It is not a substitute for supervision. Three moments call for a steady hand: the first exposure, taboo obsessions, and work with the family when accommodation is massive.
How to use it
Read the whole thing before the first session. Sections 3 to 12 lay down the frame without which exposure becomes a trial of strength; sections 13 to 28 are worth rereading the day before each session.
Every session is described on the same frame: the objective, a step-by-step run-through, what you say, the common mistakes, and the criterion for moving on. That last point sets the pace: the programme advances by acquisition, not by calendar.
3. The clinical picture
What the patient describes
Patients rarely talk about obsessions. They talk about habits, about perfectionism, about a need for control, or they say nothing at all. The delay before a first request for help is long, often more than ten years, and longer still when the obsessions concern shameful content.
Two elements make up the disorder.
Obsessions are recurrent thoughts, images or urges, experienced as intrusive and unwanted, which provoke marked anxiety. The patient does not recognise them as truly their own: that is what distinguishes them from ordinary worry. "What if I left the gas on", "what if I hit someone with the car", "what if this thought means I am a paedophile", "what if I contaminate my daughter".
Compulsions are acts or mental operations the patient feels compelled to perform in order to reduce anxiety or prevent a feared event. Checking, washing, counting, ordering, repeating, but also praying mentally, reviewing a scene, reassuring oneself internally, seeking the feeling that something is right.
The five presentations and what they change
Contamination. Washing, avoidance of places and objects, a cascade of objects that have become unclean. Exposure is easy to design, hard to sustain.
Checking. Doors, gas, taps, sent emails, car journeys. The difficulty is that checking produces a less vivid memory, which increases doubt: the more you check, the less you remember.
Taboo obsessions. Aggressive, sexual or blasphemous content, often concerning children or family members. Compulsions here are mainly mental, and patients rarely consult for it. This is the most poorly treated presentation, and the most burdensome in suffering.
Symmetry and incompleteness. Here the anxiety is not that of a catastrophe but a sense that something is not as it should be. The motivation is sensory rather than probabilistic, which changes the formulation.
Obsessions with no visible compulsion. These rarely exist in a pure state: look for mental rituals, they are always there.
What keeps the disorder going
The patient believes that not acting would be irresponsible, and the ritual produces immediate relief. That relief is the problem: it prevents the discovery that the catastrophe would not have happened, and it credits the ritual with a power it does not have. Every ritual performed reinforces the obligation to perform the next.
Three processes add to this. Attention fixes on the threat, which makes it omnipresent. The search for certainty becomes the goal, when certainty is unattainable. And the family joins in, in good faith, by reassuring, by checking on the patient's behalf, by making accommodations.
Epidemiology, in two useful figures
Lifetime prevalence is in the region of 1 to 3 % (Ruscio et al., 2010). Onset is bimodal, with a peak in adolescence and a second in early adulthood; onset after forty should prompt a search for another cause.
The impact is high: obsessive-compulsive disorder is among the most disabling conditions on World Health Organization estimates, because of its chronicity and the time the rituals consume.
4. The model that guides this programme
Why this one
Exposure with response prevention is the best-established psychological treatment for obsessive-compulsive disorder. It does better than clomipramine alone, and the combination is not clearly superior to it (Foa et al., 2005). Meta-analyses place it first among psychological interventions (Öst et al., 2015).
Salkovskis's cognitive model (1985, 1999) explains why it works, and above all why it fails when applied mechanically. An intrusive thought is a universal phenomenon: most people have them, and do nothing with them. What turns one into an obsession is the interpretation placed on it, and particularly the idea of personal responsibility for possible harm. The ritual follows from that interpretation; it is not its cause.
Rachman (1997, 1998) specified two complementary mechanisms. Thought-action fusion: believing that having a thought amounts almost to having done it, or increases the likelihood of it. And the importance attached to the thought: the more significant a thought is judged to be, the more it returns.
The five levers
Exposure. The patient deliberately comes into contact with what they fear, until their anxiety falls of its own accord, and without a ritual.
Response prevention. This is the half that decides the outcome. Exposure without prevention teaches nothing, because the patient credits the absence of catastrophe to the ritual.
The interpretation. What the patient believes their thought means has to be examined and tested: responsibility, probability, the meaning of the thought.
Mental rituals and reassurance. Invisible, they sabotage the whole programme if they are not identified one by one.
Tolerance of doubt. The final goal is not certainty, it is being able to act without it.
What the model implies you should not do
Never reassure. Answering "do you think I could have contaminated someone?" is a ritual you are performing on the patient's behalf. The reply is always of the same kind: "I cannot tell you, and that is exactly what we are working on."
Do not debate the content of the obsession. Demonstrating that a thought is absurd produces a few hours of relief and a request for another demonstration the following week. You work on the interpretation and the behaviour, not on the truth of the content.
Do not over-grade. A hierarchy of thirty steps in which the patient spends six months on the first three is not graded exposure, it is organised avoidance with your consent.
Do not confuse relaxation with exposure. Relaxation during exposure becomes one more ritual.
5. The DSM-5-TR criteria, reformulated
The criteria below are a reformulation in our own words, as an aide-memoire. They do not replace the manual: consult the DSM-5-TR (American Psychiatric Association, 2022) for the letter of the text and the application notes.
Obsessive-compulsive disorder requires the following.
The presence of obsessions, compulsions, or both.
Obsessions are defined by two features: recurrent and persistent thoughts, images or urges, experienced as intrusive and unwanted, which cause anxiety or distress; and the person's efforts to ignore them, suppress them, or neutralise them with another thought or an action.
Compulsions are likewise defined by two features: repetitive behaviours or mental acts the person feels driven to perform in response to an obsession or according to rigid rules; and the fact that they aim to prevent or reduce anxiety, or to prevent a feared event, without being realistically connected to what they claim to prevent, or being clearly excessive.
Time consumed or significant suffering: the symptoms take up time, generally more than an hour a day, or cause marked distress or impairment of functioning.
Exclusion of other causes: the effect of a substance or a medical condition, and the absence of another mental disorder that would better account for the picture.
Three important specifiers. The degree of insight, from good to absent with delusional beliefs. The presence, current or past, of tics, which changes prognosis and sometimes medication. And the nature of the content, which is not a formal specifier but which should be recorded.
What these criteria do not say, and what you must assess
They do not list mental rituals, which are nonetheless present in the majority of patients and which decide the success of treatment.
They do not measure family accommodation, which is a major maintaining factor and a predictor of relapse.
They say nothing about the interpretation, which is the cognitive target. An assessment that stops at the diagnosis gives you nothing to work with.
Frequently asked questions
Do you really need sixteen sessions? My patients rarely come more than ten times.
Volume matters, and NICE sets a threshold of ten therapist hours for moderate to severe disorder. If you only have ten sessions, do not compress everything: keep sessions 1 to 4 and session 16 intact, and sacrifice generalisation and the boosters — knowing that relapse is decided there. It is better to announce a shorter, incomplete treatment from the outset than to give a diluted version of this one.
A patient refuses all exposure. What do I do?
Do not negotiate the exposure, work the formulation. A refusal is almost always a sign that the patient has not understood what the ritual does in their own disorder, or that they are afraid of losing control. Go back to session 2, run very small and very conclusive experiments, and offer a first item you are confident they will manage. Persistent refusal after four sessions of formulation raises the question of motivational ambivalence, to be treated as such.
How do I know whether an action is a ritual or a normal precaution?
Three criteria, in order of usefulness. Function: is it done out of habit, or to bring anxiety down? Flexibility: can the patient not do it, on a day when they are in a hurry? And ending: does the action have a natural end, or does it stop when the feeling is right? An action that stops at the feeling is a ritual, however ordinary it looks.
The patient says they perform no mental rituals. Should I believe them?
Rarely. This is not concealment: they do not recognise them as rituals, because they seem like thinking. Ask differently: "when the thought arrives, what do you do to make it go away?" and "what do you say to yourself?" Then offer the list from session 3, form by form.
What do I say when the patient asks for reassurance?
Always the same thing, without variation: "I cannot tell you, and that is exactly what we are working on." The invariance is what gives the reply its value. You can add, once and for all: "if I answer you, I am performing your ritual for you, and you will have to come back and ask me again." Do not explain it every time: the explanation itself becomes reassuring.
A patient has thoughts of assaulting their child. Do I have to report it?
An obsession is not an intention. The typical picture — an unwanted, anxiety-provoking, ego-dystonic thought, with avoidance of the child and the absence of any behaviour — is not a risk factor and is not a matter for reporting. You must, however, conduct a risk assessment, once, seriously: history of violence, intent, planning, insight, substance use, crisis context. Record it. If it concludes on the obsessional picture, treat it as such — and do not go back to it every week, or your own reassessment will become the patient's ritual.
Should depression be treated first?
Mild to moderate depression improves along with the disorder: treat them together. Severe depression, with marked slowing or suicide risk, is treated first — exposure requires energy and a capacity to engage that the depressed patient does not have. Say so explicitly to the patient and set a date to resume, otherwise the postponement looks like abandonment.
The patient is on a serotonin reuptake inhibitor. Should we wait until they stop?
No. Begin. Two cautions only: do not change the dose between sessions 4 and 12, so as not to confound the effects, and identify the anxiolytic taken as needed, which functions exactly like a ritual.
How long should an exposure last?
Until anxiety has fallen by at least half, and a minimum of forty-five minutes in session. What matters is not the duration in itself but the ending: an exposure that finishes at the peak teaches the patient that they needed to get out. If anxiety does not fall at all, look for the mental ritual before concluding anything.
The patient responded well, then a new theme appeared. Is that a relapse?
No, it is the mechanism relocating, and it is frequent. The treatment is the same, and the patient already knows how to run it. Two or three sessions of method are usually enough. Warn them at session 14: a patient who has been warned treats their own new theme; a patient taken by surprise concludes that the therapy was useless.
Can this programme be run in a group?
Group formats exist and give respectable results, with an advantage in cost. They suit taboo obsessions poorly, where the patient will not speak, and severe presentations that require long individualised exposures. A mixed format — group for psychoeducation and formulation, individual sessions for the exposures — is a reasonable compromise.
What do I do about patients who check on the internet?
Treat it like reassurance: catalogue, agree, stop entirely. It is often the hardest ritual to remove, because it is permanently available and because it disguises itself as information. One useful instruction: no searches on the obsessional theme at all, of any kind, including on reputable sites.
The patient does all their exposures, with no anxiety, and nothing changes.
Two hypotheses. Either the items are too easy — look at the ratings, they will tell you. Or a mental ritual accompanies every exposure and neutralises it. In both cases the solution is the same: look for what is going on in their head, and go up a level.
Should I do a home visit?
In contamination and checking presentations, it is very often decisive, because home is where the ritual has organised itself and where exposure has never taken place. A visit between sessions 6 and 12 is worth several sessions at the consulting room. Check what your professional framework and your insurance allow.
How long should I keep a patient whose improvement is partial?
Extend by four to six targeted sessions, naming precisely what remains to be treated, rather than running a whole programme again. If nothing shifts after that extension, the question is no longer the number of sessions: go back over section 31 point by point, or refer.