Makindo Medical Notes Comprehensive Medical Encyclopedia | Education for Healthcare Professionals

Mental capacity is the ability of a person to make a specific decision at the time it needs to be made. For healthcare professionals, assessing capacity is both a legal obligation and a clinical responsibility. Students and junior doctors must be confident in recognising when to assess capacity and when to escalate concerns.

📜 Legal Framework (UK)

The Mental Capacity Act (2005) governs decisions for adults in England & Wales.
Presumption of capacity unless proven otherwise.
Capacity is decision-specific and time-specific.
Any intervention for those lacking capacity must be in their best interests.
Always choose the least restrictive option.

⚖️ The Four-Stage Test of Capacity

Patients must be able to:

🗣️ Understand information relevant to the decision.
🧩 Retain that information long enough to make a choice.
🧮 Weigh the pros and cons of different options.
🗨️ Communicate their decision by any means (verbal, written, non-verbal).

🚩 Red Flags – When to Suspect Impaired Capacity

Patient refusing treatment in a way that doesn’t align with their values or prior beliefs.
Evidence of confusion, delirium, dementia, severe learning disability, intoxication, or psychosis.
Rapidly fluctuating mental state (e.g., sepsis, hypoglycaemia, delirium).
Unrealistic or bizarre explanations for choices.

🩺 Approach for Doctors & Students

👂 Listen carefully: Many patients just need clearer explanations or more time.
📝 Document thoroughly: Note why capacity was questioned, what information was provided, and how the patient responded.
🧑‍⚕️ Escalate early: Involve seniors, psychiatry liaison, safeguarding teams if unsure.
📚 For students: Observe assessments, practice structured history-taking, and learn to use simple language when explaining decisions to patients.

💡 Advice for Clinical Practice

Always assume capacity unless there is clear reason to doubt it.
Capacity is about the process of decision-making, not whether you agree with the outcome.
Involve family/carers if appropriate, but remember the decision is ultimately the patient’s (unless lacking capacity).
If lacking capacity: act in best interests, considering patient’s prior wishes (advance statements, LPA).
When urgent (e.g. life-saving treatment) → act first, document later.

🧑‍⚕️ Common Clinical Scenarios (Cases)

Case 1 – Refusing Surgery An 80-year-old with a hip fracture refuses surgery, saying "the doctors want to poison me".

Red flag: delusional reasoning → capacity is impaired.
Next step: Assess formally, involve psychiatry if needed, act in best interests (likely proceed with surgery).

Case 2 – End of Life Decisions A patient with advanced dementia is unable to communicate and develops pneumonia.

No capacity → check advance directives or LPA (if in place).
If none: best interests decision with MDT + family discussion (e.g. ceiling of care, DNACPR).

Case 3 – Student Dilemma A medical student is asked to witness a capacity assessment but notices the patient doesn’t fully understand the risks of refusing antibiotics.

Action: Raise concerns with supervising doctor – students have a duty of candour too.
Learning: Never be afraid to voice uncertainty, it protects the patient.

🎯 Key Takeaways

Capacity is decision- and time-specific.
Use the 4-step test for assessment.
Document everything clearly – protects both patient and clinician.
Escalate concerns early; students should always involve seniors.
Ethical tension: autonomy vs best interests – navigate with care and guidance.

Mental capacity concerns