If you are 18 years and over, you are presumed to have decision-making capacity. No one will question this unless there is a reason to. Even so, at some stage your decision-making capacity may become impaired by disease or injury, or even drugs or alcohol. You might lose decision-making capacity permanently (for example, if you sustain serious irreversible brain damage), or temporarily (for example, if you are put into an induced coma). In order to have decision-making capacity, you must be able to: Understand the nature of the decision that is being made (including the information provided to you in relation to that decision); Understand the risks and consequences of the decision (and be able to weigh them up); and Be able to communicate the decision (whether verbally or otherwise).   If there is any doubt as to your decision-making capacity we strongly recommend you have this confirmed by your GP and upload their summary report with your Advance Care Plan. This will offer reassurance to anyone seeking to rely on your Advance Care Plan later, that you understood your decisions when making them. It will increase the likelihood that your Advance Care Plan will be complied with, and your wishes followed. Remember that even if you have dementia or are unable to understand some things, it does not necessarily mean you do not have decision-making capacity to make an Advance Care Plan. However if there is any reason your decision-making capacity might be impaired, it is even more important to have a formal assessment by your GP.