An explanation, not a repeated history #
A formulation is the clinician's reasoned understanding of a particular person's difficulties. It brings together the presenting syndrome, development, relevant context, alternative explanations and implications for care. Base it on established facts and explicitly identified hypotheses. Revise it as new information emerges. A formulation can be useful before a final diagnosis is established; a diagnostic label alone cannot explain why this person is struggling now or what help may be useful.
| Task | Purpose | Question |
|---|---|---|
| Summary | Condense the important facts. | What happened and what was found? |
| Diagnosis | Classify the presentation using appropriate requirements. | Which category best fits the available evidence? |
| Formulation | Explain an individual pattern and guide next steps. | How may factors interact, and what needs addressing? |
A discriminating opening paragraph #
Start with relevant background, baseline function, principal difficulties, duration, course and impact. Add key examination findings and significant medical, medication or substance information. Select demographic information for clinical relevance rather than reciting every social label. Attribute collateral information and describe limitations. Do not substitute 'reliable and adequate' for an explanation of which parts were corroborated and which remain uncertain.
- What changed from the person's usual functioning?
- Which findings support the leading interpretation?
- Which detail changes the differential or immediate assessment?
- What does the person identify as the main problem and desired outcome?
Five Ps: a thinking framework #
The five Ps organize the present problem and possible contributing factors. Consider biological, psychological and social domains within each, rather than putting all biology under predisposition and all relationships under precipitation. A factor may have several roles depending on timing. Family history may suggest vulnerability, while current family responses may support recovery or maintain distress. Do not invent a mechanism because a framework has an empty box.
| Heading | What belongs here | Question |
|---|---|---|
| Presenting | Current experiences and impairment. | What needs attention now? |
| Predisposing | Earlier vulnerabilities or background. | What may have increased susceptibility? |
| Precipitating | Changes shortly before onset. | What preceded this episode? |
| Perpetuating | Processes associated with persistence. | What may keep the difficulty going? |
| Protective | Capabilities, relationships and resources. | What helps, and how accessible is it? |
Separate evidence and inference #
For each explanation identify its supporting observation, alternatives and information needed to test it. An event preceding illness is not automatically its cause. A difficult relationship does not prove a personality structure. Describe a plausible maintaining cycle from the person's examples: poor sleep may reduce concentration; falling behind may increase worry; worry may interfere with sleep. Establish that these links occur rather than imposing the cycle on everyone with similar symptoms.
Make the differential useful #
Consider a small number of plausible alternatives and relevant coexisting conditions. State what supports each, what conflicts and what is missing. Use chronology, symptom quality, physical findings, exposures and inter-episode functioning to discriminate. Include medical and substance-related explanations when indicated. Avoid an undifferentiated list. If a diagnosis is provisional, explain why. A classification code follows clinical assessment rather than replacing it.
- Would a medical, neurological or medication-related process explain the pattern better?
- Did experiences occur independently of intoxication or withdrawal?
- Which question, examination or record would change the leading interpretation?
Connect the explanation to care #
State priorities arising from the explanation: missing information, physical or cognitive assessment, immediate concerns, communication needs, practical support and possible psychological or social interventions. Treatment decisions require individualized clinician assessment rather than automatic prescribing from a formulation. Include preferences and realistic barriers. Prognosis should discuss relevant uncertainty, supports and modifiable factors; it should not promise recovery or pronounce safety.
- Tie proposed investigations to questions they could answer.
- Distinguish immediate assessment needs from longer-term goals.
- Specify involvement and consent or communication needs.
- Reassess when important information is unavailable or presentation changes.
Synthetic example: a working explanation #
A fictional trainee has six weeks of insomnia, fatigue and missed classes after moving. They describe longstanding performance worry, financial pressure and late-night studying followed by exhaustion. A supportive friend and previously effective planning are resources. The working formulation identifies an impairing mood/anxiety-related presentation requiring assessment; it does not assume the move caused a disorder. Mood symptoms, exposure history and physical health information remain incomplete. Next steps clarify these questions, assess current clinical concerns and discuss practical support and sleep-related behaviour.
Check the formulation with the person #
Present the explanation in everyday language and invite disagreement: 'Does this fit your experience, or have I missed something important?' Revise it when priorities or evidence change. A shared formulation need not mean agreement with every hypothesis. Document uncertainty and preserve its practical purpose: helping the team and the person decide what to understand or address next.