3. Capacity, children and best interests
Adults — Mental Capacity Act 2005 (England and Wales)
Start by assuming an adult has capacity. Capacity is decision-specific and can change. A person lacks capacity for a decision if, because of an impairment or disturbance of the mind or brain, they cannot understand, retain, use or weigh the relevant information, or communicate a choice, even with support.
Five statutory principles (paraphrased)
- Assume capacity unless it is established otherwise.
- Take all practicable steps to help the person decide before concluding they cannot.
- An unwise decision is not, by itself, lack of capacity.
- Any act or decision made for someone who lacks capacity must be in their best interests.
- Choose the option that is least restrictive of their rights and freedom.
Scotland and Northern Ireland have their own capacity frameworks. Use the law that applies where you practise, and your local safeguarding/capacity pathway.
Helping someone decide
Use plain language, pictures, a quieter room, a trusted supporter if the patient wants one, and extra time. Do not treat “they signed last time” as consent for a different treatment today.
If the person lacks capacity
Check for a lasting power of attorney for health and welfare, a court-appointed deputy, or an advance decision that applies. If none of those decide the issue, a best-interests decision is made — involving those who know the person, and an Independent Mental Capacity Advocate where the Act requires one. Emergency treatment to save life or prevent serious deterioration can proceed under the Act’s protection if you reasonably believe it is in the person’s best interests.
Children and young people
A child who has sufficient understanding and intelligence to understand the proposed treatment (sometimes called Gillick competence) may be able to consent. For those who cannot, someone with parental responsibility usually consents. If parents disagree, or a young person refuses treatment you believe is essential, do not improvise — seek advice from a senior colleague, your indemnity organisation and, where needed, safeguarding or legal routes.
How this links to modules 2 and 3
Module 2 covers what you write down and who you tell. Module 3 covers what happens when the patient is unhappy. Consent discussions that were rushed or poorly recorded are a common root of complaints.
Always follow current GDC Standards, the capacity law in your UK nation, and your practice consent protocol.