What is Mental Capacity?

To have mental capacity means being able to make your own decisions. We all make decisions, big and small, everyday of our lives and most of us are able to make these decisions for ourselves, although we may seek information, advice or support for the more serious or complex ones.

The law says someone lacking capacity cannot do one or more of the following four things:

  • Understand information given to them
  • Retain that information long enough to be able to make a decision
  • Weigh up the information available to make a decision
  • Communicate their decision.


For large numbers of people their capacity to make certain decisions about their life is affected either on a temporary or on a permanent basis. The Mental Capacity Act covers situations where someone is unable to make a decision because the way their mind or brain works is affected, for instance, by illness or disability, or the effects of drugs or alcohol. A lack of mental capacity could be due to:

  • A stroke or brain injury
  • A mental health problem
  • Dementia
  • A learning disability
  • Confusion, drowsiness or unconsciousness because of an illness or the treatment for it
  • Substance misuse.


In all of these instances the person may lack capacity to make particular decisions at particular times. It does not necessarily mean that they lack capacity to make any decisions at all. A person with a learning disability may lack the capacity to make major decisions, but this does not necessarily mean that they cannot decide what to eat, wear and do each day. A person with mental health problems may be unable to make decisions when they are unwell, but able to make them when they are well.

Many people provide health treatment or social care support to people who may have difficulties making some or all decisions about their lives. If the person is aged over 16 years and living in England or Wales, then the Mental Capacity Act applies to how professionals and other paid carers work with them. Specifically they must follow the guidance set out in the Act's Code of Practice unless there is a good reason for not doing so.


Accessibility notice: Making text larger in your browser

  • Making text larger in Firefox 1.5 / 2 / 3

    Follow these steps to increase or decrease the size of the text for the web page you are viewing:

    1. Open the ' View ' menu with the mouse or by press ' Alt ' and ' V ' at the same time
    2. Select the ' Text Size ' option with the mouse or by pressing 'Z'
    3. Increase or decrease the text size with the mouse or by using the up and down arrow keys and pressing ' Enter '
    Alternatively you can press ' Ctrl ' and ' + ' to increase the text size, ' Ctrl ' and ' - ' to decrease the text size. ' Ctrl ' and ' 0 ' returns you to the default 'normal' size
  • Making text larger in Internet Explorer 7

    For the first time in Internet Explorer a zoom feature is included which allows you to enlarge the whole browser window; to do this:

    1. Press ' Ctrl ' + ' + ' to increase the zoom and ' Ctrl ' + ' - ' to decrease the zoom
  • Making text larger in Internet Explorer 5 / 6

    For the first time in Internet Explorer a zoom feature is included which allows you to enlarge the whole browser window; to do this:

    1. Open the ' View ' menu with the mouse or by pressing ' Alt '+' V '
    2. Select the ' Text Size ' option with the mouse or by pressing ' X '
    3. Choose your preferred text size with the mouse or by using the up and down arrow keys and pressing ' Enter ' or by clicking on it
    4. The text on our website should now have changed to reflect your choice

Listen to this website

You can listen to this website by downloading a free tool called Browsealoud onto your computer. This tool will read out website content.

This service is useful for people:

  • with low literacy and reading skills
  • who speak English as a second language
  • with dyslexia
  • with mild visual impairment

You can download a copy of this software from the Browsealoud website at http://www.browsealoud.com/