Capacity

Capacity is the ability to make a particular decision for yourself at the time it needs to be made.

Updated 12 October 2026 (1 minute read)

Summary

  • The Mental Capacity Act 2005 covers people aged 16 and over in England and Wales.
  • Every adult is assumed to have capacity unless it is shown otherwise.
  • A person lacks capacity if they cannot understand the information, retain it, weigh it up or communicate a decision.
  • Capacity belongs to one decision at one time. Someone may be able to decide what to eat and unable to decide about surgery.
  • An unwise decision is not evidence that someone lacks capacity.

Interview questions

  • How would you assess whether a patient has capacity?
  • A patient makes a choice you think is foolish. Does that mean they lack capacity?
  • Who decides for a patient who lacks capacity?

Practise answering these with a mentor

Our interview preparation has you answer questions like these out loud, with feedback on each answer.

More NHS hot topics, medical ethics case studies and medical school interview questions are in AlphaMED Resources, which we add to and update through the application cycle.