One major conundrum in the field of law and neuroscience is that the mental states that are most relevant to legal determinations are often mental states that occurred in the past, and can longer be assessed. Could the defendant, at the time he committed the crime, have had the cognitive capacity to satisfy the required mens rea for the crime charged? Was an individual's tortious conduct intentional or inadvertent? Even if the field of neuroscience eventually gains the ability to provide data relevant to understanding of immediate mental states, those data will be unavailable to legal actors by the time someone is actually interested in gathering them. (1)
The issue of mental competency in criminal cases is an exception to this general problem. (2) Unlike most other relevant mental states in the law, competency deals with a criminal defendant's current mental state, during the litigation itself. (3) Does the defendant understand the nature of the charges and the proceedings? Does he have the ability to communicate with and assist his lawyer? If neuroscience has the potential to shed light on these questions, it can be very useful, because the defendant is readily available and neuroscience data could potentially be gathered as soon as the issue is raised.
Scholarship in the law and neuroscience arena has exploded in the past ten years. (4) Surprisingly, however, relatively little scholarship has been written addressing the potential for neuroscience to aid in competency evaluations. We do not have clear data as to how often neuroscience is used in competency evaluations by experts or in hearings conducted by courts. There is virtually no literature discussing how neuroscience data, at our current level of understanding, might be able to aid in determining competency. This article aims to begin to fill that gap. The article proceeds in three Parts. In Part I, I outline the U.S. law governing competency in criminal cases and describe the most common way that experts providing opinions to the court on that subject carry out competency evaluations. In Part II, I review recent empirical studies examining the use of neuroscience in courts of various jurisdictions, and focus particularly on those studies' descriptions of the use of neuroscience in competency proceedings. I also conduct an anecdotal survey of recent cases involving neuroscience in competency decisions. In Part III, I examine several areas in which neuroscience has the potential to make a greater contribution to competency determinations. A brief conclusion follows.
MENTAL COMPETENCY IN THE U.S. LEGAL SYSTEM
One of the fundamental requirements of due process in the American criminal justice system is that a criminal defendant must be considered competent before he can be tried for his alleged crimes. (5) Indeed, this concept was established in legal systems before the United States was even formed. In his Commentaries on the Laws of England, William Blackstone provided the foundational reasoning for why an incompetent defendant lacks the ability to make a plea or go to trial within the bounds of due process:
If a man in his sound memory commits a capital offence, and before arraignment for it, he becomes mad, he ought not to be arraigned for it; because he is not able to plead to it with that advice and caution that he ought. And if, after he has pleaded, the prisoner becomes mad, he shall not be tried; for how can he make his defence? (6) Essentially, the concept goes, though a mentally incompetent defendant is physically present in the courtroom, he is not mentally present at a level sufficient to defend himself, and so a trial against him would amount to a trial in abstentia--a historically disfavored violation of due process. (7)
The U.S. Supreme Court has articulated this basic requirement on several occasions. The most prominent is Dusky v. United States. (8) In that case, the defendant was charged with kidnapping a young girl and taking her across state lines. (9) At his arraignment, the defendant's lawyer suggested "that there was a question of the defendant's mental competency to stand trial," and the district court accordingly ordered an evaluation "to determine, insofar as possible, whether... the defendant was possessed of sufficient mental and moral faculties as to be capable of distinguishing between right and wrong and to be conscious of the nature of the acts which he was then doing or committing." (10) The examiners determined that the defendant was schizophrenic, and that he would be unable to understand the nature of the proceedings against him and aid in his defense. (11) Despite this, the district court found the defendant competent to stand trial, and he was convicted. (12) After the Eighth Circuit affirmed, the Supreme Court reversed, and delivered the now-familiar two-part test as to whether a defendant is competent to make a plea or stand trial: the district court must determine (1) "whether [the defendant] has sufficient present ability to consult with his lawyer with a reasonable degree of rational understanding" and (2) "whether he has a rational as well as factual understanding of the proceedings against him." (13)
Later cases applied and elaborated on the underlying principle announced in Dusky. For example, in Drope v. Missouri, the Court explained that an explicit competency determination need not be made in every case, but rather, is necessary only when a court has reason to doubt the defendant's competency. (14) In that case, the trial court had ignored substantial indicia of the defendant's lack of competence to stand trial, including medical evaluation, the defendant's wife's testimony as to his erratic behavior, and his own attempted suicide. (15)
Congress has also codified rules regarding competency determinations, based largely on the standard laid out in Dusky. As part of the Insanity Defense Reform Act of 1984, Congress enacted 18 U.S.C. [section] 4241, which provides rules for "[d]etermination of mental competency to stand trial or to undergo postrelease proceedings." (16) Section 4241 provides that either the prosecutor or defense may file a motion for a hearing to determine the defendant's competency. (17) The court is then required to hold a hearing "if there is reasonable cause to believe that the defendant may presently be suffering from a mental disease or defect rendering him mentally incompetent to the extent that he is unable to understand the nature and consequences of the proceedings against him or to assist properly in his defense." (18) After the court holds a hearing, it must then determine, by a preponderance of the evidence, whether the defendant is actually suffering from such a mental disease or defect so as to be rendered incompetent. (19) If that is the case, the court must then "commit the defendant to the custody of the Attorney General," who must house the defendant under further conditions of the Act. (20)
The end result of the case law and statutory scheme is a robust constitutional right. The competency of a defendant to stand trial, plead guilty, or be sentenced is a jurisdictional legal issue, and accordingly it cannot be waived. (21) And whether a defendant is competent is a status of the defendant, not a defense that a defendant raises; unlike an insanity defense, a defendant does not concede his guilt of the crime by claiming that he is incompetent. (22)
How Does the Court Evaluate Competency?
The Supreme Court has not articulated specific factors for courts to assess in determining whether the Dusky standard has been satisfied, and so individual jurisdictions have articulated their own sets of considerations, though they often overlap. For example, the Sixth Circuit has explained:
In making [the competency] determination, the district court must consider several factors, including the defendant's demeanor, any prior medical opinion regarding competency, and evidence of irrational behavior. An attorney's opinion about his client's competency is likewise a relevant factor. Moreover, although a defendant may show signs of paranoia or other mental illness, "such an illness would not necessarily render the defendant incompetent to stand trial." In short, "there are... no fixed or immutable signs which invariably indicate the need for further inquiry to determine fitness to proceed; the question is often a difficult one in which a wide range of manifestations and subtle nuances are implicated." (23) While no single consideration is considered to be more important than any other one, the court itself is extremely restricted in the context in which it is able to observe and evaluate the defendant. Typically, the court has only seen the defendant at a few hearings (such as an initial appearance, arraignment, or detention hearing) before the defendant either pleads or goes to trial. Further, the defendant is not required to speak extensively at any of these hearings. (24) Accordingly, courts often exercise their discretion under 18 U.S.C. [section] 4241(b) to "order that a psychiatric or psychological examination of the defendant be conducted, and that a psychiatric or psychological report be filed with the court." (25) Because of the court's relative lack of familiarity with the defendant, as well as the court's lack of expertise in determining mental capacity, competency determinations often turn on the result of the psychiatric or psychological evaluation (or evaluations). (26)
As with the court, evaluating psychiatrists and psychologists are not subject to many specific requirements in making their competency evaluations. (27) Among the broad considerations frequently considered are "to what extent, if any, [the defendant] is mentally [disabled], disoriented, suffers impairment of recent or remote memory, has impaired thought processes, experiences hallucinations or delusions, and whether his behavior is agitated, bizarre, incoherent...