Mental capacity and best interests

In England and Wales, the Mental Capacity Act 2005 covers people aged 16 and over. It starts from a presumption: your young person is assumed to be able to make their own decisions unless it is shown otherwise, and they must be given real help to decide before anyone concludes they cannot.

Capacity is decision-specific. A young person might have capacity to choose what to wear and what to eat but not, at a given moment, to weigh up a complex medical choice. There is no such thing as failing capacity in general, so a service that treats one assessment as covering everything is applying the law wrongly.

When someone genuinely lacks capacity for a particular decision, that decision must be made in their best interests, taking their own wishes and feelings into account, and the people who know them well, including parents, should be consulted. This framework is why services start addressing letters to your child at 16: it is a change in who decides, not a cut-off Cut-off A line drawn through a range of scores. On one side a service may offer an assessment or support, on the other side it may not. Read the full definition of Cut-off of your involvement.