Mental capacity

Mental capacity is the ability to perform a specific juristic act by understanding and making a decision to do something that has legal consequences, such as make a Will, a power of attorney or a gift, or to provide consent for something. Mental incapacity is the inability to do something or to provide consent for something by reason of a mental disorder or disability. Lack of mental capacity is not always constant; it may fluctuate. It will also vary according to the function that requires the decision or consent and, for this reason, mental capacity is referred to as being ‘function specific’.

Lack of capacity must not be confused with eccentricity—everyone is entitled to make decisions that to others may seem odd. The autonomy to make a decision has to be tempered by an understanding that some people do not have the capability to understand the decision-making process. Generally, it is assumed that a person has capacity to make their own decisions, unless proven otherwise, however, where there are concerns about an individual’s capacity, a prudent practitioner should investigate further.

The Mental Capacity Act 2005 (