Mental Capacity Assessment

The Mental Capacity Act 2005 (MCA) presumes all adults have capacity unless proven otherwise. Capacity is decision-specific and time-specific — a patient may lack capacity for one decision but retain it for another. The four-stage test must be…

Mental Capacity Act 2005 Four-Stage Test

The pathway

1 · Stage 1 — Impairment/disturbance

Does the person have an impairment or disturbance in the functioning of their mind or brain?
Examples: dementia, delirium, intoxication, brain injury, psychiatric illness, severe learning disability
If NO → person has capacity (assessment ends)
If YES → proceed to Stage 2

2 · Stage 2 — Does the impairment affect this decision?

Does the impairment/disturbance affect their ability to make this specific decision at this time?
If NO → person has capacity
If YES → assess the four functional abilities (Stages 3a–3d)

3 · Stage 3a — Can they UNDERSTAND?

Can the person understand the information relevant to the decision?
Use simple language, visual aids if needed
Provide information in an accessible format
Understanding does not require perfect recall

4 · Stage 3b — Can they RETAIN?

Can the person retain the information long enough to make a decision?
Short-term retention is sufficient — does not need to be permanent
Strategies: written information, repeat consultations

5 · Stage 3c — Can they WEIGH UP?

Can the person use or weigh the information as part of the decision-making process?
Inability to weigh: acute psychosis, severe depression, mania
Note: a patient can make an unwise decision and still have capacity

6 · Stage 3d — Can they COMMUNICATE?

Can the person communicate their decision by any means?
Any method counts: speech, writing, AAC devices, eye gaze, gesture
Only fails this test if no method of communication is possible

7 · If lacks capacity — Best Interests

Follow Section 4 MCA Best Interests checklist
Consider: past wishes, values and beliefs, advance decisions (ADRT), Lasting Power of Attorney (LPA) holder (health & welfare)
Involve family/carers and IMCA (Independent Mental Capacity Advocate) if appropriate
Least restrictive option principle
DoLS: if admission to hospital or care home deprives liberty in a person lacking capacity — complete Deprivation of Liberty Safeguards (DoLS) form
Complex decisions → Court of Protection

8 · Document thoroughly

WHO assessed capacity, WHEN, and for WHICH decision
What information was given and in what format
Why they were found to have/lack capacity (which stage failed)
What was decided in their best interests and who was consulted
Record any ADRT or LPA reviewed

When to escalate

Patient refusing life-saving treatment and capacity is uncertain — urgent senior/psychiatric review and legal advice,Advance Decision to Refuse Treatment (ADRT) present — verify validity and applicability before proceeding,Deprivation of liberty without DoLS authorisation — complete DoLS paperwork urgently (unlawful deprivation is a human rights breach),No LPA/ADRT and family disagreement with clinical best interests decision — Court of Protection application,Fluctuating capacity in acute delirium — reassess frequently, treat reversible causes, delay non-urgent decisions,Patient under 16 with disputed capacity/refusal — parental consent or court order; consult paediatric team and legal

Reference: Mental Capacity Act 2005 / MCA Code of Practice 2007

This page is the reference half

The app adds what a web page cannot: a VINDICATE differential builder, worked on-call scenarios with full A–E findings, recall practice, and all of it offline.