Best interests
What it means
When an adult lacks capacity for a decision, it is made in their BEST INTERESTS (not just medical interests). Consider: the person's past/present wishes, feelings, beliefs and values; views of family/carers/anyone with legal authority (LPA/deputy); whether they may regain capacity (and could the decision wait?); and the least restrictive option. An IMCA is instructed for serious decisions where there is no one to consult.
Worked example
An incapacitous patient's known religious objection to a treatment must be weighed in the best-interests decision even though he cannot now express it — best interests is holistic, not purely clinical.
In the exam
A decision must be made for a permanently incapacitous patient with no family; the team weighs his previously expressed values and instructs an independent mental capacity advocate.
What settles it
Best interests ≠ 'what the doctor thinks is medically best' — it must incorporate the person's own values and the views of those close to them.
Classically confused with
Advance decision (ADRT) & LPA
Source: MCA 2005 best-interests checklist