Mental Capacity

The Mental Capacity Act 2005 provides a statutory framework to empower and protect people who may lack capacity to make decisions for themselves. It also establishes a framework for making decisions on their behalf.  This applies whether decisions are for  life changing events or for everyday matters. All decisions made must comply with the Mental Capacity Act.

The Mental Capacity Act outlines five statutory key principles that underpin the work with adults who may lack mental capacity:

  • A person must be assumed to have capacity unless it is proved otherwise
  • A person is not to be treated as incapable of making a decision unless all practicable steps to help them reach a specific decision have been taken without success
  • A person is not to be treated as incapable of making a decision merely because seeming to make unwise decision/s
  • Any decision made or action taken for a person who lacks mental capacity to do so for themselves, must be made or taken in their best interests
  • A decision made on behalf of someone who lacks the mental capacity to do so for themselves, must always be made in the least possible restrictive way.

Mental capacity always needs to be assessed time and decision specific

That means for example that a person might have capacity to make decisions about one area of their life but not about others. It also means that it might be necessary to carry out more than one mental capacity assessment, if there are different decisions to be made or if decisions are to be made at different times.


How to assess mental capacity

Mental capacity assessments can be completed by a range of professionals including social care and health staff. Who is best placed to be the lead person carrying out a mental capacity assessment depends on the decision to be made, but it is always good practice to consult with other relevant people and professionals as part of the assessment process.


To assess mental capacity a two stage functional test has to be completed, covering the following key questions:

Stage one: Does the person have an impairment of, or a disturbance in the functioning of their mind or brain? This could include, but is not limited to, learning disabilities, mental illness, brain injury, dementia, memory loss, etc.

Stage two: Does the impairment or disturbance mean that the person is unable to make a specific decision when they need to?

A person is deemed to lack mental capacity if unable to:

  • understand the information salient to the decision to be made
  • retain the information of the decision to be made
  • use or weigh up the information necessary to the decision making process
  • communicate their decision by any means

When carrying out a mental capacity assessment, it is important to consider medical diagnosis, disability or other forms of impairment and needs of the person to be assessed and to use tools and communication aids, which might help the person to engage in the assessment process.