Case formulation: the complete practical guide (with worked examples)

Every year I ask a new group of trainees the same question on their first morning: “What is a formulation?” And every year I get roughly the same three answers. A diagram with arrows. The bit of the assessment report after the history. Something your supervisor asks for and you write the night before.

None of those is wrong, exactly. But they miss the reason formulation matters. A good formulation is the moment an assessment stops being a list of facts about a person and becomes an explanation: of why this person, with this history, is struggling with this problem, now, and what is keeping it in place. Get that right and the treatment plan almost writes itself. Get it wrong, or skip it, and therapy tends to drift from week to week, following whatever arrived in the room that morning.

This guide covers formulation from first principles to everyday practice. It’s long, because the subject deserves it, but it’s organised so you can jump to the part you need. There are four interactive tools along the way: a sorting exercise, a maintenance cycle explorer, a builder for your own formulations and a health check to run on them.

What a formulation is (and isn’t)

A formulation is a hypothesis about a person’s difficulties, built from psychological theory and from what you know about them, that explains how those difficulties developed and what maintains them, and that guides what you do next. Lucy Johnstone and Rudi Dallos, who edited one of the standard textbooks on the subject, describe it as the tentative summary of a client’s difficulties that links theory and practice and guides intervention. Willem Kuyken, Christine Padesky and Robert Dudley use a lovely image: a crucible, in which the client’s experience and the therapist’s theory are combined to produce something new that neither had on their own.

Three features run through almost every definition:

• It explains, rather than describes. “Has panic attacks in shops” is a description. “Reads a racing heart as a heart attack, escapes, and so never learns the sensation is safe” is an explanation.
• It’s a hypothesis. A best guess, held lightly, tested in treatment and revised when the evidence says so.
• It’s useful. It points to what to do. A formulation that doesn’t change your plan is an essay.

Formulation and diagnosis

Formulation is sometimes set up as the opposite of diagnosis, and the debate can get heated. In practice, most clinicians use both, for different jobs. A diagnosis is a category: it groups people with similar difficulties, links you to research on what tends to help, and opens doors to services. A formulation is personal: it explains why this person has these difficulties, which a diagnosis can’t do. Two people with the same diagnosis of depression can need quite different treatment, and the formulation is where you find out why.

	Diagnosis	Formulation
Answers	What kind of problem is this?	Why this person, why now, and what keeps it going?
Built from	Symptom criteria	Theory plus this person’s history, context and meanings
Shared with client	Usually as a label	Ideally developed together, in their words
Changes over time	Rarely	Constantly, as you learn more
Best for	Communication, research, access to services	Planning and personalising treatment

The evidence, honestly

It would be easy to write a guide like this as if formulation were proven to improve outcomes. It isn’t, not straightforwardly, and you should know that. Studies comparing formulation-driven treatment with standard protocols have produced mixed results, and research on the reliability of formulations, including work by Kuyken and colleagues in the mid-2000s, suggests clinicians agree reasonably well on the descriptive parts of a formulation but much less on the deeper, more inferential parts, such as core beliefs.

So why bother? Partly because the alternative isn’t “no formulation”. Every therapist works from some implicit theory of what’s going on; formulation makes it explicit, so it can be checked, shared and corrected. Partly because formulation is how you decide what to do when a protocol doesn’t fit, which in routine practice is often. And partly because clients frequently say it was the moment things started to make sense. That’s not a randomised trial, but it’s not nothing.

Levels of formulation

Formulations come in different depths, and it helps to know which one you’re building. Kuyken, Padesky and Dudley describe three levels, which develop over the course of therapy rather than all at once:

1. Descriptive. Putting the presenting problems into psychological terms. What happens, when, and how the parts connect. Usually possible in the first session or two.
2. Cross-sectional (maintenance). How the problem keeps itself going here and now: the cycles of thoughts, feelings, body sensations and behaviour. This is the level most short-term treatment works at.
3. Longitudinal (developmental). How early experiences shaped the beliefs and strategies that make this person vulnerable. Needed for long-standing or recurrent problems, and when the cross-sectional work gets stuck.

A common trainee mistake is to go straight for level three: deep, satisfying stories about childhood before anyone has worked out what happens on a Tuesday afternoon in the supermarket. Start at the surface. Go deeper when the work needs it.

The 5 Ps

The most widely taught framework for organising a formulation is the 5 Ps. It isn’t tied to a single therapy model, which is part of its appeal: you can fill it with cognitive, behavioural, systemic or psychodynamic ideas. Each P asks a different question.

P	Question	Typical content
Presenting	What is the problem?	Current difficulties, in the client’s words; frequency, severity, impact
Predisposing	What made the person vulnerable?	Early experiences, family patterns, temperament, trauma, long-held beliefs, biological factors
Precipitating	Why now?	Events, losses, transitions or stresses around the time of onset
Perpetuating	What keeps it going?	Avoidance, safety behaviours, thinking patterns, relationships, circumstances
Protective	What helps?	Strengths, relationships, skills, values, previous coping, hopes

Of the five, the perpetuating factors matter most for treatment, because they’re the ones you can change. You can’t alter what happened at twelve or undo the event that set things off. You can help someone drop a safety behaviour, test a belief or change a routine. When time is short, put most of your effort here.

The protective factors are the ones most often forgotten. They matter for two reasons. They’re resources you’ll use in treatment. And a formulation made only of problems can land as a verdict, especially when a client reads it. Every formulation I sign off in supervision has at least three.

Practise: meet Sam

Sam is a fictional client, but a very familiar one. They’re 31, a primary school teacher, and they’ve come to therapy with panic attacks that started six months ago, now accompanied by low mood and time off work. Below are twelve facts from Sam’s assessment. Sort each into the P it belongs to. A few are deliberately tricky.

If you put the reassurance-seeking under protective, you’re in good company, and you’re not entirely wrong. Sam’s partner’s care is a genuine strength. But the pattern of asking for reassurance many times a day works like any other safety behaviour: brief relief, then the doubt returns, slightly stronger. Formulations are full of things that are both, and the skill is noticing which role they’re playing right now.

Maintenance cycles: what keeps it going

The heart of most cognitive behavioural formulations is the maintenance cycle: a picture of how thoughts, emotions, body sensations and behaviour feed each other in a particular situation. The simplest version, often drawn as four overlapping circles around a situation, was popularised by Christine Padesky and Kathleen Mooney in 1990 and is affectionately known as the “hot cross bun”.

Its power is in the arrows. A thought (“I’m having a heart attack”) produces fear, fear produces bodily sensations, the sensations seem to confirm the thought, and the behaviour that follows (escape, checking) brings relief while preventing the person from finding out they were wrong. Each part keeps the others going. And each part is a place where treatment can step in.

Notice that the generic cycle works for all three problems, but what fills it is quite different, and so are the interventions. That’s why disorder-specific models exist. For panic, David Clark’s 1986 cognitive model puts the catastrophic misinterpretation of body sensations at the centre. For social anxiety, Clark and Adrian Wells’s 1995 model adds self-focused attention and the way people build a distorted picture of how they appear to others. For PTSD, Anke Ehlers and Clark’s 2000 model focuses on the nature of trauma memories and the meanings attached to the trauma. When a well-tested model exists for the problem in front of you, use it as the skeleton and personalise it.

Drawing it with a client

The best maintenance cycles are drawn live, in session, from a recent specific example. Not “what usually happens” but “last Thursday in the supermarket, tell me what happened”. Specific examples give you real thoughts in real words, which are far more useful than a summary. A sequence that works well:

1. Choose a recent, vivid example, ideally from the past week.
2. Start with the situation: where, when, who was there.
3. Ask what they noticed first. Some people start with a sensation, some with a thought.
4. Follow the sequence round: “And when you thought that, what did you feel? And then what did you do?”
5. Ask what happened next, including the short-term relief and the longer-term cost.
6. Step back together: “Looking at this, what do you notice?”

That last step is where formulation becomes therapeutic. A client who notices for themselves that checking their pulse keeps their attention on their heart has learned something no amount of explanation could have taught them.

Longitudinal formulations: how it developed

Some problems are recent and contained: a specific phobia that started after a specific event. Others are long-standing, recurrent or tangled up with how a person sees themselves. For those, a maintenance cycle explains the Tuesday afternoon but not the twenty years. That’s when you need a longitudinal formulation.

The classic cognitive version, developed from Aaron Beck’s work and set out in detail by Judith Beck, runs like this:

1. Early experiences shape how a person understands themselves, others and the world.
2. These become core beliefs: deep, often unspoken conclusions, such as “I’m unlovable” or “the world is dangerous”.
3. To live with those beliefs, people develop rules and assumptions: “If I keep everyone happy, they won’t leave”, “If I’m always prepared, nothing bad will happen”.
4. These lead to compensatory strategies, such as perfectionism, people-pleasing or constant vigilance, which work, mostly, for years.
5. Then a critical incident breaks a rule or activates the belief directly, and the problem begins.
6. The maintenance cycles then keep it going.

For Sam, a longitudinal sketch might read: growing up with a father who had a heart attack and a mother who treated every symptom as a possible emergency, Sam learned that the body is fragile and that danger can strike without warning. A rule developed: “If I stay alert to my body, I’ll catch problems in time.” This worked well enough until the day Sam fainted at a wedding, which seemed to prove that danger had arrived. Since then, vigilance has become checking, and checking has become panic.

A full worked example

Here is Sam’s formulation written out as it might appear in a letter or set of notes after four sessions, followed by the treatment plan that follows from it. Notice how each part of the plan links back to something in the formulation.

From the formulation	In the treatment plan
Racing heart read as a heart attack	Psychoeducation on panic; behavioural experiments testing the prediction
Pulse checking, carrying water, reassurance-seeking	Identify and gradually drop safety behaviours; agree a plan with Sam’s partner
Avoiding shops and motorways	Graded exposure, starting with a corner shop
Fear of body sensations	Interoceptive exposure; returning to running
Low mood linked to loss of work and routine	Activity scheduling; phased return-to-work plan
Belief that the body is fragile (longitudinal)	Revisit in later sessions if panic improves but health worry remains

Build your own

Now try it with one of your own clients, or with Sam if you’d rather start with the example. Write in plain language, as if the client might read it. The one-page diagram on the right builds as you type, and you can copy it straight into your notes. Nothing you type is stored or sent anywhere.

If you find a box stays empty, that’s useful information too. Often it means a question you haven’t asked yet. An empty precipitating box, for instance, might mean you haven’t asked what was happening in the client’s life when things began, or it might mean the problem crept up slowly, which is worth writing down as well.

Beyond the 5 Ps: other ways to formulate

The 5 Ps and the cognitive models are the most widely taught, but they aren’t the only ways of making sense of someone’s difficulties. Different traditions emphasise different things, and knowing a few helps you choose the right lens for the person in front of you.

Approach	Main focus	Useful when
Cognitive behavioural	Thoughts, beliefs, behaviours and the cycles that maintain problems	Clear, current problems such as anxiety and depression
Psychodynamic	Unconscious conflicts, defences and repeating relationship patterns, often mapped with Malan’s triangles of conflict and person	Relationship patterns that keep repeating; feelings that seem out of proportion
Systemic	Relationships, family patterns and communication, often drawn with a genogram	Problems that live between people, families and couples, children and young people
Cognitive analytic (CAT)	Reciprocal roles and the procedures people use to manage them, drawn as a map	Relationship difficulties, self-harm, patterns that repeat across many settings
Power Threat Meaning Framework	How power operates in a person’s life, the threats it poses, the meanings they make and how they respond	When social and structural factors, such as poverty, abuse or discrimination, are central

Many experienced therapists formulate integratively: a 5 Ps structure, a cognitive maintenance cycle, a few systemic observations about the family, and an awareness of the power and circumstances shaping it all. That’s fine, as long as the result is still coherent, still one page, and still points to what you’ll do.

Culture, context and power

A formulation can quietly locate every problem inside the person: their beliefs, their behaviours, their history. Sometimes that’s accurate. Often it’s only half the story. Someone who is anxious about going out may be living with racial harassment on their street. Someone whose mood dropped after redundancy may be dealing with debt, not distorted thinking about debt. A good formulation makes room for that.

• Ask about context directly. Housing, money, work, caring responsibilities, discrimination, community, faith.
• Check the meaning, not just the event. The same loss can mean different things in different families and cultures.
• Notice your own assumptions. What counts as “normal” family closeness, or “appropriate” expression of distress, varies widely.
• Don’t pathologise sensible responses. Vigilance in an unsafe environment is not a cognitive distortion.
• Include protective factors from the community. Faith, extended family and cultural identity are often powerful sources of resilience.

Sharing a formulation with a client

Most modern approaches to formulation are collaborative: built with the client, not presented to them. Even so, there comes a moment when the pieces are put together and the client sees the whole picture, and that moment needs care.

Research suggests most clients find a shared formulation helpful, but not all, and not without mixed feelings. In a study of cognitive therapy for psychosis published in 2003, Paul Chadwick and colleagues found that while many clients valued their formulation, some also found it saddening or worrying to see their difficulties laid out so plainly. That’s worth bearing in mind with anyone, not only in psychosis.

How to do it well

• Build it piece by piece over several sessions rather than unveiling a finished diagram.
• Use their words and their examples, not technical language.
• Present it as a hypothesis: “This is our best guess so far. What fits? What doesn’t?”
• Start with the maintenance cycle, which tends to feel hopeful (“this is something we can change”), before moving to history.
• Always include strengths, and say them out loud.
• Check the emotional impact: “How is it to see it laid out like this?”
• Give them a copy, if they want one, and invite them to change it.

From formulation to treatment plan

This is the test of any formulation: does it tell you what to do? A practical way to check is to go through the perpetuating factors one by one and ask, “What would loosen this?” The answers are your treatment plan. Then go through the protective factors and ask, “How can we use this?”

If the formulation includes…	Treatment might include…
Avoidance	Graded exposure, approach goals
Safety behaviours	Identifying and dropping them, behavioural experiments
Catastrophic predictions	Behavioural experiments, testing predictions
Rumination or worry	Noticing the process, worry postponement, attention training
Withdrawal and inactivity	Behavioural activation, activity scheduling
Harsh self-criticism	Compassion-focused work, examining the critic’s origins and function
Trauma memories that intrude	Trauma-focused therapy, such as trauma-focused CBT or EMDR
Relationship patterns that repeat	Working with the pattern as it shows up, including in the therapy relationship
Practical stressors such as debt or housing	Signposting, advocacy, problem-solving, joint work with other services

If you find interventions in your plan that don’t connect to anything in the formulation, either the plan has drifted or the formulation is missing something. Both are worth knowing.

Revising the formulation

A formulation is a working document. You’ll learn things in session eight that you couldn’t have known in session two: a memory that surfaces, a pattern that becomes visible in the therapy relationship, a treatment that should have worked and didn’t. Each of these is a reason to revise.

• Set review points, such as after the first block of sessions, at a mid-point review and before ending.
• Revise when treatment stalls. Stuck therapy is often a sign the formulation has missed something important.
• Revise when something surprising happens. Surprises are data.
• Date each version, so you and the client can see how your understanding has developed.
• Use it at the end: a final formulation is the basis of a good relapse-prevention or staying-well plan.

Common mistakes

After many years of reading trainees’ formulations, and writing plenty of imperfect ones myself, these are the mistakes I see most often.

• Too long. If it doesn’t fit on a page, it’s a history. Keep what explains.
• Too clever. Elaborate theoretical language impresses supervisors and confuses clients. Write so the client could read it.
• All past, no present. Rich childhood material and nothing about what keeps the problem going this week.
• No strengths. A formulation without protective factors is incomplete and can be hurtful.
• Written alone. Formulations built without the client tend to be less accurate and less used.
• Never revised. The formulation from session two, untouched at session twenty.
• Disconnected from treatment. A good formulation, followed by a generic plan that ignores it.
• Ignoring context. Every problem placed inside the person, even when circumstances are doing much of the work.

Check your own

Take a formulation you’ve written recently and run it through the eight questions below. Be honest. The tips appear as you answer, and most formulations, mine included, have at least one gap.

Formulation in teams and supervision

Formulation isn’t only for the therapy room. In multidisciplinary teams, a shared formulation can help colleagues understand a client whose behaviour has been confusing or frustrating, and shift the conversation from “what’s wrong with them” to “what happened to them, and what’s keeping it going”. Team formulation meetings, where a psychologist facilitates the team in building a formulation together, are now common in many mental health services.

In supervision, bringing a formulation rather than a narrative focuses the discussion. Instead of “let me tell you about this client”, try “here’s my current formulation, here’s where I think it’s weakest, and here’s what I’m stuck on”. Supervisors can do much more with the second.

Summary

• A formulation is a hypothesis that explains how a person’s difficulties developed and what keeps them going, and guides what you do.
• Start at the surface, with a maintenance cycle, and go deeper only when needed.
• The 5 Ps give you a structure; perpetuating factors are where treatment acts; protective factors are never optional.
• Build it with the client, in their words, and present it as a best guess.
• Include context, culture and circumstances, not just what’s inside the person.
• Check that every part of the treatment plan links back to the formulation.
• Revise it as you learn, and use the final version to plan for staying well.

A last thought. The best formulation I ever saw was written by a client, not a therapist. At the end of a long piece of work, she drew it on the back of an appointment card: three circles, four arrows and the words “I check because I’m scared, and I’m scared because I check.” It was more accurate than anything in my notes. That, in the end, is what we’re aiming for.