If you’ve been informed that a loved one no longer has mental capacity, perhaps following an unexpected illness or injury, this can be an emotionally fraught time where important decisions may need to be made about either their immediate or long-term care.

By understanding what it means when someone lacks capacity, and how this decision is reached by healthcare professionals, this can help to prepare you for how the diagnosis will affect your loved one and how their best interests can be safeguarded moving forward.

What does lacking mental capacity mean?

The Mental Capacity Act 2005 sets out the legal framework of how those working with or responsible for caring for someone who lacks capacity should act and make decisions on that person’s behalf. Under the Act, an individual lacks capacity in relation to a matter if: “at the material time s/he is unable to make a decision for himself/herself in relation to the matter because of an impairment of, or a disturbance in the functioning of, the mind or brain.”

As such, a person who lacks mental capacity is someone who does not possess the ability to make a particular decision for themselves at the time the decision needs to be taken. This reflects the fact that someone may lack capacity to make some decisions, but will have capacity to make others. For instance, they may be able to make minor decisions about everyday issues such as what to wear or eat, but unable to make more significant and complex decisions about say, financial matters or medical treatment. 

As a result of illness or injury that causes their capacity to change, a person may also lack the ability to make decisions at a certain time, yet be able to make that decision at a later time. 

How is lacking mental capacity decided?

Having identified whether an individual suffers from an illness, injury or other issue that could cause the person to lack mental capacity (the diagnostic stage), the healthcare professionals tasked with deciding if someone lacks capacity will then need to consider the individuals ability to make certain decisions for themselves (the functional stage). 

A person will be classed as unable to make a decision for themselves if they’re unable to:

•   understand the information that's relevant to a particular decision

•   retain that information for as long as is necessary to reach a conclusion

•   use or weigh that information as part of the decision-making process, or

•   communicate their decision by talking, using sign language or by any other means.

 How should someone lacking mental capacity be treated?

Given the potential impact of decisions being made on behalf of those who lack capacity to make specific decisions for themselves, the legal requirements under the 2005 Act are underpinned by the following five key principles:

•   An individual must be assumed to have capacity unless it is established otherwise

•   An individual must not be treated as unable to make a decision unless all practicable steps to help him or her to do so have been taken without success

•   An individual must not be treated as unable to make a decision merely because they’ve made an unwise decision

•   Any act done or decisions made on behalf of an individual who lacks capacity must be done in their best interests

•   Anyone taking any action or making any decisions on behalf of an individual who lacks capacity must first consider any options that are less restrictive of their rights and freedoms.

The purpose of these statutory principles is to balance a person's right to make their own decisions with their right to be protected from harm if they lack capacity. If, however, you have any concerns about decisions that have been made by healthcare professionals on behalf of a loved one, including the outcome of any mental capacity assessment or what is in that person’s best interests, you should seek expert legal advice immediately.