When a patient's mental capacity to make decisions is open to question, the physician often calls in a psychiatrist to help make the determination. The psychiatrist's conclusions may be taken to a court to determine the patient's legal competency. In this article, the author presents several clinical criteria psychiatrists may use when determining patients' mental capacities. The author discusses two critical ethical questions psychiatrists should consider when they use this criteria: (1) whether they should use a fixed or sliding standard and (2) if they adopt a sliding standard, what clinical factors should be given the greatest weight. The author also discusses whether psychiatrists should take initiative to obtain a second opinion from another psychiatrist or mental health professional. Finally, the author discusses research regarding patients who are likely to have more impaired capacity for performing executive functions, patients requesting surgical procedures that are ethically without precedent, and patients possibly having inner awareness under conditions that previously were not considered possible.
Keywords: clinical decision making; determination of mental capacity; ethical decision making; legal competency.