Competency-to-stand-trial (CST) evaluations are the backbone of criminal forensic psychology practice. CST evaluations may be the most common criminal forensic psychology evaluation (Zapf & Roesch, 2009). Criminal responsibility (CR) defenses are relatively rare, used in only about 1 in 1,000 felony cases (Melton, Petrila, Poythress, & Slobogin, 2007;Packer, 2009). The number of CR evaluations completed is unknown but is likely significantly greater than the number of CR defenses actually taken to trial. The forensic psychology literature has many excellent reviews of CST and CR (e.g., Hall, 2008;Weiner & Hess, 2006). Although forensic neuropsychologists are more likely to practice in civil court, they play a growing role in criminal court as well, including CST and CR evaluations. In fact, neuropsychology is likely underused in CST and CR cases, even when brain disorder or neurocognitive deficits are suspected.This chapter provides an introduction to the concepts of CST and CR and reviews the landmark cases, precedents, and concepts involved in each. A review of the literature and legal cases specifically for neuropsychology and CST and CR is provided. True to the identity of this volume as a practical handbook, we emphasize practical issues and recommendations for conducting forensic neuropsychological CST and CR evaluations.Although CST and CR are used throughout this chapter, there are many alternate names. CR refers primarily to insanity and may be termed not guilty by reason of insanity or guilty except for insanity. The focus of a CR evaluation is the defendant's capacity to have understood, at the time of the offense, that the conduct was wrong. There are closely related issues as well, such as questions of extreme emotional disturbance (EED) or diminished capacity.CST is also known as adjudicative competency, trial competency, or fitness to proceed. Defendants found incompetent are known as incompetent to stand trial (IST). An evaluator may assess many specific competencies: to (a) waive Miranda rights, (b) confess, (c) waive counsel, (d) represent oneself, (e) make a plea, and so forth. For a discussion of these specific competencies in forensic neuropsychology see Horton and Hartlage (2010). As used in this chapter, CST refers to whether the defendant (a) has a factual and rational understanding of the legal proceedings against defendant, (b) is able to assist the attorney, and (c) is able to participate in the defense. These three concepts are often referred to the "three prongs" of CST.
PRIMER ON THE LEGAL CONCEPTS OF COMPETENCE TO STAND TRIAL AND CRIMINAL RESPONSIBILITYBoth CST and CR have long social and legal histories. In the sections that follow, we provide brief historical outlines of these concepts, intended to assist in developing an understanding of their use in today's court systems.