Objective: The main objective of this article is to evaluate and describe instruments for assessing decision-making capacity in psychiatry and psychogeriatrics, and to evaluate them for use in daily practice.

Methods: The instruments were selected in Medline articles. We focus on the relationship between these instruments and the concept of competence, represented in the following elements: context in which an instrument is developed, disclosure of information, standards to assess decision-making capacity, the scale or threshold model, and validity and reliability.

Results: The developmental context influences how information is provided and standards defined. Although it is not clear how decision-making capacity relates to competency judgments, most instruments provide good reliability.

Conclusions: Comparison of the different instruments opens directions for future research. Although instruments can never replace a physician's judgment, they may provide a clear starting point for a discussion on competence. In daily practice assessments, attention should be given to information disclosure, the influence of our own normative values in evaluating standards of decision-making capacity, and the relation between decision-making capacity and competence.