Mental capacity

Help for those who lack the capacity to make decisions.

Mental capacity is the ability to make decisions about your life. Making decisions could be affected by a disability, or medical conditions such as dementia, brain injury or stroke. You may not be able to do the following:

  • understand information given to you to make a particular decision
  • remember that information long enough to be able to make the decision
  • use or weigh up the information to make the decision
  • communicate your decision (even if it's a blink of an eye or a squeeze of a hand)

People who cannot do these things lack the mental capacity to make decisions. This can apply to major decisions, for example about personal finance, social care or medical treatment, or everyday decisions such as what to wear or eat.

Some important points to note are:

  • everyone is assumed to have the capacity to make decisions for themselves if they are given enough information, support and time
  • an unwise or eccentric decision is not an indication of lack of capacity
  • a lack of capacity can be temporary or permanent
  • the lack of mental capacity may not apply to all decisions at all times, for example, someone with dementia might be able to think more clearly at certain times of the day
  • any action or decision made on behalf of someone must be in their best interest
  • any action or decision should aim to not restrict a person's rights and freedom of action

Who decides?

Anyone can assess mental capacity. Relatives and carers are best placed to judge whether or not someone has the capacity to make day-to-day decisions. For decisions about things like medical treatment or legal issues, professionals such as doctors or solicitors may need to assess mental capacity.

The Mental Capacity Act 2005  Code of Practice (opens in a new window) must be used when you are supporting someone who lacks mental capacity. 


An Independent Mental Capacity Advocate (IMCA) is someone who can help people without mental capacity to express their views and wishes.

IMCAs mainly become involved in decisions about medical treatment or accommodation where it is provided by the NHS or a local authority. NHS bodies and local authorities have a duty to consult the IMCA in such decisions involving people who have no family or friends. 

More information (opens in a new window) is on the government website

Dorset Advocacy (opens in a new window) provide the IMCA service for Bournemouth, Christchurch and Poole.

Page last updated: 18/08/2021 11:37