What are the implications of the Mental Capacity Act 2005 for my practice when assessing a patient's decision-making ability?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 22 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

The Mental Capacity Act 2005 requires practitioners to assume that a person has capacity unless there is evidence to suggest otherwise .

Capacity is decision-specific and involves being able to make a particular decision at the time it needs to be made .

To lack capacity, a person must be unable to understand, retain, use or weigh information related to the decision, or communicate their decision, due to an impairment or disturbance in the mind or brain .

Practitioners must ensure all practicable steps to support decision-making have been taken before concluding incapacity .

Effective assessment involves thorough, proportionate, and collaborative approaches, including involving communication aids and specialists if needed .

Supporting decision-making involves helping the person understand and weigh information without coercion, respecting their autonomy, and building trusting relationships .

Practitioners should document and update information about the person's wishes, beliefs, and preferences to inform assessments and support .

Decisions that are unwise do not automatically indicate incapacity; a person can make a decision that appears risky or unwise and still have capacity .

Educational content only. Always verify information and use clinical judgement.