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Excuse: Insanity

Empirical Data And Myths



Researchers agree that, in the small universe of successful insanity defense pleaders, a person with a history of major mental illness, who has sought help for that illness, and whose victim is a member of the immediate family (certainly a non-stranger) will be most likely to be found NGRI by a jury. Both successful and unsuccessful insanity pleaders are more frequently single, caucasian, somewhat older, and better educated than the usual defendant group, unemployed at the time of the insane offense, and with a history characterized by chronic unemployment, prior psychiatric treatment, drug abuse, alcohol abuse, and previous arrests.



In the wake of the Hinckley verdict, commentators began to examine carefully the "myths" that had developed about the insanity defense, in an effort to determine the extent to which this issue has been distorted in the public eye. The research shows that (1) the insanity defense opens only a small window of nonculpability; (2) defendants who successfully use the NGRI plea "do not beat the rap"; and, perhaps more importantly, (3) the tenacity of these false beliefs in the face of contrary data is profound.

Myth #1: The insanity defense is overused. All empirical analyses have been consistent: the public at large and the legal profession (especially legislators) dramatically and grossly overestimate both the frequency and the success rate of the insanity plea, an error that is undoubtedly abetted by the media's bizarre depictions, distortions, and inaccuracies in portraying individuals with mental illness charged with crimes. The insanity defense is used in only about 1 percent of all felony cases, and is successful just about one-quarter of the time.

Myth #2: Use of the insanity defense is limited to murder cases. In one jurisdiction where the data have been closely studied, contrary to expectations, slightly less than one-third of the successful insanity pleas entered over an eight-year period were reached in cases involving a victim's death. Further, individuals who plead insanity in murder cases are no more successful in being found NGRI than persons charged with other crimes.

Myth #3: There is no risk to the defendant who pleads insanity. Defendants who asserted an insanity defense at trial, and who were ultimately found guilty of their charges, served significantly longer sentences than defendants tried on similar charges who did not assert the insanity defense. Unsuccessful NGRI pleaders are incarcerated for a 22 percent longer time than individuals who never raise the plea (Braff, Arvantes, Steadman, Detention Patterns of Successful and Unsuccessful Insanity Defendants, 21 Criminal. 439, 445 (1983)). The same ratio is found when only homicide cases are considered.

Myth #4: NGRI acquittees are quickly released from custody. Of the entire universe of individuals found NGRI over an eight-year period in one jurisdiction, only 15 percent had been released from all restraints; 35 percent remained in full custody, and 47 percent were under partial court restraint following conditional release. A comprehensive study of California practice showed that only 1 percent of insanity acquittees were released following their NGRI verdict and that another 4 percent were placed on conditional release; the remaining 95 percent were being hospitalized. In other recent research, Stephen Golding and his colleagues discovered, in their study of all persons found NGRI in the Canadian province of British Columbia over a nine-year period, that the average time spent in secure hospitalization or supervision was slightly over nine and one-half years.

Myth #5: NGRI non-murderer acquittees spend much less time in custody than do defendants convicted of the same offenses. Contrarily, two-thirds of the NGRI acquittees—those who are not murderers—spend almost double the amount of time that defendants convicted of similar charges spend in prison settings, and often face a lifetime of post-release judicial oversight. In California, while the length of confinement for individuals acquitted by reason of insanity on murder charges was less than for those convicted, defendants found NGRI for other violent crimes were confined twice as long as those found guilty of such charges, and those found NGRI of nonviolent crimes were confined for periods over nine times as long.

Myth #6: Criminal defendants who plead insanity are usually faking. This is perhaps the oldest of the insanity defense myths, and is one that has bedeviled American jurisprudence since the mid-nineteenth century. Of the 141 individuals found NGRI in one jurisdiction over an eight-year period, there was no dispute that 115 were persons with schizophrenia (including 38 of the 46 cases involving a victim's death), and in only three cases was the diagnostician unwilling or unable to specify the nature of the patient's mental illness. Also, most studies show that 80–84 percent (see Perlin, Jurisprudrence, at 111 n.178), depending on study, of NGRI defendants have significant histories of prior hospitalizations.

Myth #7: Most insanity defense trials feature "battles of the experts." The public's false perception of the circus-like "battle of the experts" is one of the most telling reasons for the rejection of psychodynamic principles by the legal system. A dramatic case such as the Hinckley trial thus "reinforced the public's perception that the insanity defense is characterized by battles of experts [who] overwhelm" the jury, engendering judicial and public skepticism as to the ability of psychiatrists to actually come to reasoned and reasonable judgments in cases involving mentally disabled individuals charged with crime.

The empirical reality is quite different. In a Hawaii survey, there was examiner congruence on insanity in 92 percent of all cases; in Oregon, prosecutors agreed to insanity verdicts in 80 percent of all cases. Most importantly, these are not recent developments: over thirty-five years ago, a study of the impact of the Durham decision in Washington, D.C., found that between twothirds and three-quarters of all insanity defense acquittals were uncontested. In short, the empirical evidence refuting this myth has been available to judges, legislators, and scholars since almost a decade prior to the adoption of the ALI–Model Penal Code test in Brawner.

Myth #8: Criminal defense attorneys—perhaps inappropriately—employ the insanity defense plea solely to "beat the rap." Attorneys representing mentally disabled defendants have—for decades—been routinely criticized for seeking refuge in the insanity defense as a means of technically avoiding a deserved conviction. In reality, the facts are quite different. First, the level of representation afforded to mentally disabled defendants is frequently substandard. Second, the few studies that have been done paint an entirely different picture; lawyers also enter an insanity plea to obtain immediate mental health treatment for their client, as a plea-bargaining device to insure that their client ultimately receives mandatory mental health care, and to avoid malpractice litigation. Third, the best available research suggests that jury biases exist relatively independent of lawyer functioning, and are generally not induced by attorneys.

Since the mid-1980s, researchers and other scholars have been patiently rebutting these myths. The publication by Henry Steadman and his colleagues of their extended multi-jurisdiction study of virtually every empirical facet of insanity defense pleading proves—beyond any doubt—that the basic tenets are mythic. The extent to which the dissemination of these data alters the terms of the insanity defense debate will reveal whether these myths, in fact, can be reinterpreted by lawmakers and the general public.

Additional topics

Law Library - American Law and Legal InformationCrime and Criminal LawExcuse: Insanity - Development Of Insanity Defense Doctrine, Post-m'naghten Developments., Hinckley And Its Aftermath