The NHS definition of capacity is “the ability to use and understand information to make a decision, and communicate any decision made.” This is very similar to competence, which is the patient’s ability to understand provided information and make a rational decision based on this by themselves. The only difference is that competence is used more in a legal setting, while capacity is used in a medical setting when making decisions about treatment. In order for a patient to have capacity they must be able to:
- Understand the information provided
- Retain the information for a reasonable period of time
- Weigh up different information in order to make a decision
- Relay and express their decision to another person
Only when these four requirements are met does a patient have capacity to make their own decisions. Most people are assumed to have capacity, including those with learning disabilities and dementia etc. until they are proven otherwise. For patients with these conditions, all attempts should be made in order to ensure that they understand all information relayed to them. For example, using simple language and writing information down for the patient to help their memory.
In cases where decisions are made when a person has capacity, and then capacity is lost, the original wishes of the patient are carried out. If the patient does not have capacity, they may appoint someone to make informed decisions for them (through lasting power of attorney), else the doctor must do whatever is in the patient’s best interests. However, in cases where there is serious questioning or debate about the best interests of someone without capacity, then this can be referred to the court of protection for further ruling.