Class presentation 3: how information about a patient is organised into an explanation of their presentation. Ten questions plus the take-home question. Plan 15–20 minutes.
Purpose: understand how information about a patient is organised into an explanation of their current presentation.
1. What is a psychiatric formulation?
- A formulation is a short, reasoned explanation of why this particular person has developed these particular difficulties at this particular time, and what is keeping them going, written so that it leads to a management plan.
- It pulls together the history, examination and investigations into a coherent story, using a model (usually the biopsychosocial model).
- It is individual: two patients with the same diagnosis have different formulations.
- It is a working hypothesis, revised as you learn more.
2. How is a formulation different from a diagnosis?
| Diagnosis | Formulation | |
|---|---|---|
| Asks | "What disorder might this be?" | "Why is this person presenting this way, now?" |
| Based on | Symptom patterns matched to criteria | The whole person: history, context, meaning |
| Gives | A label and a category | An explanation and a plan |
| Is | Shared by many people | Unique to the patient |
| Guides | Which treatments are generally effective | What to target first, how, and why |
| Changes | When criteria are met or not | As understanding grows |
They work together: the diagnosis tells you what the illness is likely to be; the formulation tells you what to do for this person.
3. Biological, psychological and social factors
- The biopsychosocial model (George Engel, 1977) says health and illness arise from the interaction of biological, psychological and social factors, none of which is enough on its own.
- Biological: genes and family history, brain structure and chemistry, physical illness, medications, substances, sleep, pregnancy and hormones, injury.
- Psychological: personality and temperament, thinking style (for example catastrophising), coping, attachment and early experience, self-esteem, beliefs, past trauma, learned behaviour.
- Social: family and relationships, housing, money and employment, education, culture and religion, stigma, loneliness, conflict, community and social support.
4. Examples in each domain
| Domain | Examples |
|---|---|
| Biological | Family history of depression; HIV or another chronic illness; head injury; alcohol, khat or cannabis use; steroid treatment; poor sleep; postpartum hormonal change |
| Psychological | Anxious, perfectionist personality; harsh self-criticism; childhood abuse or loss; avoidant coping; hopelessness; low self-efficacy |
| Social | Unemployment or debt; relationship breakdown; bereavement; living alone or far from family; exam pressure; stigma; supportive family; strong faith community |
5. The four time-based factors
| Factor | Meaning | Question it answers | Example |
|---|---|---|---|
| Predisposing | Make a person vulnerable over the long term | Why this person? | Family history, childhood trauma, anxious temperament |
| Precipitating | The trigger that tips vulnerability into illness | Why now? | Bereavement, exam failure, drug use, loss of job |
| Perpetuating | Keep the problem going or make it worse | Why does it continue? | Poor sleep, avoidance, ongoing conflict, non-adherence, isolation |
| Protective | Reduce risk or help recovery | What is helping, and what can we build on? | Supportive family, faith, employment, good insight, treatment access |
6. How these become the "4Ps" of formulation
Place the three domains (biological, psychological, social) against the four Ps. That gives a grid of 12 cells, and every cell is a prompt for a question:
| Predisposing | Precipitating | Perpetuating | Protective | |
|---|---|---|---|---|
| Biological | ||||
| Psychological | ||||
| Social |
You fill the grid from the history, then write the explanation that links the cells.
7. Can a factor belong to more than one category?
Yes. The category depends on the role it plays in the timeline, so the same factor can sit in several places.
- Alcohol use: predisposing (long-standing heavy use), precipitating (a binge before the episode) and perpetuating (continued use worsens mood and sleep).
- Poor sleep: a precipitant of a manic or depressive relapse and a perpetuating factor once ill.
- Unemployment: precipitating (losing the job) and perpetuating (financial strain, no routine).
- A supportive family: protective but can become perpetuating if high expressed emotion (critical or over-involved) is present.
8. Why a plain list of biological, psychological and social factors is not enough
- A list describes; a formulation explains.
- It does not show how the factors interact (for example job loss → drinking → conflict → low mood → hopelessness).
- It does not prioritise which factors matter most or which can be changed.
- It does not answer "why now?" or "why this person?"
- It does not lead to the treatment plan.
- Without the narrative, two clinicians with the same list may plan completely different, unlinked care.
9. A good formulation answers three questions
- Why did this person develop these difficulties? (predisposing factors, how they interact)
- Why now? (precipitating factors)
- What is keeping it going? (perpetuating factors) and what can help? (protective factors)
A good formulation: is brief (one paragraph or less), links factors with "because" and "which led to", takes account of culture and meaning, is shared with the patient, and ends with a plan for each part (for example treat insomnia, address alcohol use, mobilise family support, give CBT).
10. Clinical application: a worked example
Wanjiru, 24, a final-year student, presents with 6 weeks of low mood, poor sleep, weight loss and thoughts that she is a burden. She started drinking heavily after failing a major exam. Her mother has "depression". She lives alone far from home. A close friend has been checking on her.
| Predisposing | Precipitating | Perpetuating | Protective | |
|---|---|---|---|---|
| Biological | Mother with depression (family history) | Poor sleep and weight loss as the illness began | Insomnia, alcohol use, poor diet | Good physical health |
| Psychological | Perfectionism, harsh self-criticism | Failing the exam, seen as total failure | Rumination, hopelessness, avoidance | Wants to get better, some insight |
| Social | Lives far from family | Academic pressure, exam result | Isolation, withdrawal from classes, money worries | Supportive friend, university counselling available |
Formulation (narrative): Wanjiru has a biological vulnerability to depression through her family history and a perfectionistic, self-critical style. The failed exam, in a young woman living alone under academic pressure, acted as the precipitant and she began to drink to cope. Heavy drinking, poor sleep, isolation and ruminative thinking are now maintaining and worsening her depression and raising her suicide risk. Her supportive friend and her wish to recover are strengths.
Plan from the formulation: assess and manage suicide risk; antidepressant and/or CBT for the depression; reduce alcohol; treat insomnia; involve the friend and family; academic support (deferral, counselling); follow-up.
Take-home question
> Diagnosis asks, "What disorder might this be?" Formulation asks, "Why is this particular person presenting this way, at this particular time?"
- Diagnosis is shared and categorical; formulation is personal and explanatory.
- Diagnosis tells you what family of treatments exists; formulation tells you what to do first for this person and why.
- A diagnosis without a formulation risks treating a label; a formulation without a diagnosis misses what is known about the illness. Good practice uses both.
Presentation checklist
- Define formulation; formulation versus diagnosis table
- The three domains with examples
- The four Ps and the 12-cell grid
- One factor in several cells, and why lists are not enough
- The worked case on a grid, then the narrative formulation and plan
- Closing line: why this person, why now, and what is keeping it going