Does the person have mental capacity to make a decision?

When a person has ‘mental capacity’ it means they are able to make a specific decision at a specific time. People who can’t do this are said to ‘lack capacity’ to make the specific decision. This might be due to an injury. Or they might have a learning disability, a mental illness, or a condition that affects their brain – such as dementia.

To have mental capacity a person must be able to:

  • understand the information that is relevant to the decision they want to make
  • keep the information in their mind long enough to make the decision
  • weigh up the information that is available to make the decision
  • communicate their decision in any way – including talking, using sign language, or through simple muscle movements such as blinking their eyes or squeezing someone’s hand.

How might mental capacity be affected in a person with dementia?

When a person has dementia their mental capacity can change over time. It can also change in both the short term and the long term. For example, there might be days or even times of the day when the person can think more clearly. This means they may have capacity to make a decision at some times but lack capacity at other times.

A person may also have the capacity to make some decisions but not others. For example, a person may be able to decide that they want to go on holiday but not be able to make choices between transport or accommodation options. This is because some decisions involve having to take in more information, which may be harder for the person to process or understand.

Some decisions, such as whether to move into a care home, also involve many factors to weigh up and this may also be harder for the person to consider. Therefore, you should not assume that a person lacks the mental capacity to choose simpler decisions such as what they want to wear or eat just because they can’t make difficult financial or medical decisions.