Mental competency refers to a person’s ability to make rational decisions and express themselves. In the legal context, mental competency means a person’s capacity to understand the basic nature and purpose of court proceedings, his/her roles with respect to other parties in the courtrooms and possible legal consequences of his/her actions.
In the U.S. the laws presume that all adults are mentally competent to make decisions and to be responsible for their acts or decisions, which recognizes people’s capacity to understand the legal consequences of their actions. The party who challenges this presumption bears the burden to prove that a person is more likely than not to be mentally incompetent. The party who claims the person is mentally incompetent may ask the court to order a mental competency evaluation carried out either by psychologist or psychiatrist.
The mere diagnosis of a mental or physical disorder may not be sufficient in itself to support a judicial determination that a person is mentally incompetent. Court usually take into consideration a totality of circumstances, including the frequency, severity, and duration of a person’s mental handicap.
[Last updated in September of 2020 by the Wex Definitions Team]