Capacity

Question 1

Decision making capacity

Answer 1

In general the law protects the right of competent adults to refuse medical treatment even if the decision is not
sensible, rational or well considered. All adults are presumed to have decision making capacity unless contrary
evidence is available. Decision making capacity is usually thought to be impaired if there is ‘some impairment
or disturbance of mental functioning so as to render him/her incapable of making decisions’. This would occur
if the person was unable to:
1. understand information relevant to the decision, or
2. retain information relevant to the decision (especially in regard to consequences), or
3. use and weigh the information as part of the decision making process, or
4. communicate the decision.

Question 2

Assessment of capacity- important points

Answer 2

The assessment of capacity is not about the quality or ‘sense’ of the decision itself but about the quality of the
decision making process. Information relevant to decision making about medical treatment includes the risks
and benefits for all options - the proposed treatment, alternatives treatments and no treatment.
If a person is unable to retain or remember information then decision making capacity can be called in to
question. It is difficult to imagine how a person can “use and weigh” information that is not retained. Case
law, in regards to dementia, tends to accept a mutual deterioration in a person’s ability to understand, weigh
and retain information

Question 3

Mental illness and lack of capacity

Answer 3

The criteria “to use and weigh information” can be influenced by mental illness and lead to a lack of decision
making capacity. A person suffering depression may understand all of the information, but because of their
negativity they may either over estimate negative features or under estimate positive features of the information
to hand. This would impair his/her ability to make a reasoned decision.
It should be noted that decision making capacity should not be in question if harmful decisions are endorsed.
If there is any doubt in a person’s ability to make decisions then the preference is to resolve in favour of the
preservation of life.