§ 25.04 Definitions of "Insanity"

§ 25.04 Definitions of "Insanity"48

[A] Putting the Insanity Tests in Historical and Legal Context

Generally speaking, five tests of insanity, discussed in subsection [C], infra, have gained support at one time or another in the United States: the M'Naghten49 rule; the "irresistible impulse" (or "control") test; the "product" standard; the American Law Institute's (ALI) Model Penal Code definition; and the federal statutory definition of insanity.

The first insanity test of modern relevance was enunciated by the English House of Lords in the M'Naghten case. It quickly became the generally accepted standard in this country. Criticism of the M'Naghten rule, however, was immediate50 and has been unending. As a result of the perceived narrowness of the test, a few courts expanded the standard of insanity by coupling the M'Naghten rule with an "irresistible impulse" test.

In 1954, the influential United States Court of Appeals for the District of Columbia promulgated the "product" or Durham rule of insanity.51 Based on an 1870 New Hampshire case,52 the Durham test was exceedingly broad, and was intended to bring insanity law more in accord with modern psychiatric knowledge. Durham represented a dramatic departure in the jurisprudence of insanity, and consequently received tremendous scholarly attention.

The Durham court itself encountered problems with the product rule, which it struggled to resolve. In 1972, however, it abandoned the rule and substituted for it a version of the ALI Model Penal Code insanity defense, originally promulgated by the Institute in 1962. The ALI test quickly attracted support from courts and legislatures. In less than two decades, it was adopted by 10 of the 11 federal circuit courts and by a majority of the states.53

The trend in favor of the ALI test seemed unstoppable until the attempted assassination of President Ronald Reagan. Public fury following John Hinckley's acquittal on the ground of insanity54 resulted in pressure to abolish the defense.55 Although the abolitionist movement generally failed, it had a significant effect on the law. Courts and legislatures began to reconsider their support for the comparatively broad ALI rule. "When the dust cleared, the sun of the Model Penal Code test had set."56 For example, California, which originally adopted the M'Naghten test, and then shifted to the ALI standard, reversed itself again and returned to M'Naghten.57 Congress, too, enacted a M'Naghten-like definition of insanity, thereby overriding the nearly unanimous adoption of the ALI test in the federal system. A few states abolished the insanity defense.58

One must put the controversy over the insanity tests in context. There is social science literature suggesting that jurors either do not consider or fail to understand the insanity instructions they are given. Jurors apparently come to a trial with their own implicit standards of criminal responsibility. These standards involve a mixture of factors, such as the defendant's motive for her conduct, history of mental illness, degree of remorse, and the specific psychiatric diagnosis.59 According to one empiricist, "jurors apply their own sense of justice when determining whether a defendant" should be found not guilty by reason of insanity.60 And, according to him, the insanity test most consistent with jurors' intuitions is one that has never been accepted by a court, namely, the so-called "justly responsible" test suggested by one federal judge.61

[B] "Mental Disease or Defect"62

[1] In General

The terms "mental illness," "mental disorder," and "mental disease or defect," on the one hand, and "insanity," on the other hand, are not synonymous. The first set of terms is used by the mental health community; the word "insanity" is a legal term. Thus, it is incorrect to say that "mental illness" is a criminal defense; "insanity" is the excusing defense.

"Mental illness" is a more encompassing term than "insanity." A person can be mentally ill without being insane; insanity, however, presupposes the existence of a mental disease or defect.

[2] Medical Definition of "Mental Disorder"

The American Psychiatric Association's manual of mental disorders concedes that "no definition [of 'mental disorder'] can capture all aspects" of the concept.63 A mental disorder is not a discrete entity. There are no sharp boundaries between "mental disorder" and "no mental disorder." That being said, the manual currently provides, in part, that a "mental disorder" is a:

syndrome characterized by clinically significant disturbance in an individual's cognition, emotion regulation, or behavior that reflects a dysfunction in the psychological, biological, or developmental processes underlying mental functioning. Mental disorders are usually associated with significant distress or disability in social, occupational, or other important activities.64

[3] Legal Definition of "Mental Disease or Defect"

All of the insanity tests presuppose that the actor suffers from a "mental disease or defect" or "disease of the mind," yet courts rarely define the terms.65 The Model Penal Code insanity defense, as well, provides no definition of the critical phrase, preferring instead to leave the issue "open to accommodate developing medical understanding."66

Only an earlier, now virtually defunct, test of insanity included a definition of the term: It defined a mental disease or defect as "any abnormal condition of the mind which substantially affects mental or emotional processes and substantially impairs behavior controls."67 Under this definition, a "disease" is a condition capable of improving or deteriorating; a "defect" is a condition incapable of changing, which may be congenital (e.g., low intelligence), the result of injury to the brain, or the residual effect of a physical or mental illness.68

[C] The Tests

[1] M'Naghten Test69

[a] Rule

The M'Naghten test of insanity is cognitive-based. According to M'Naghten, a person is insane if, at the time of her act,70 she was laboring under such a defect of reason, arising from a disease of the mind, that: (1) she did not know the nature and quality of the act that she was doing; or (2) if she did know it, she did not know that what she was doing was wrong, i.e., the accused at the time of doing the act did not know the difference between right and wrong. Currently, 27 states and the federal government apply this standard or a more restrictive version, such as applying only one of the two prongs of M'Naghten.71

As one scholar has written, "[t]he test is easier to quote than understand. Entire books have [been] devoted to deciphering it, but its meaning remains elusive."72 We will not spend an entire book deciphering the test, but various features of it are discussed immediately below.

[i] "Know": Broad or Narrow?

The word "know" used in both prongs of the test may be defined narrowly or broadly. Sometimes the word is used narrowly: A person may be found sane if she can describe what she is doing ("I was strangling her") and can acknowledge the forbidden nature of her conduct ("I knew I was doing something wrong"). This may be referred to as "formal cognitive knowledge." It is the type of limited knowledge that one might expect a child to have. But there is a potentially deeper meaning of "knowledge" ("affective knowledge"), which is absent unless the actor can evaluate her conduct in terms of its impact on others and appreciate the total setting in which she acts, i.e., can "internalize the enormity of the[ir] criminal act" and, thus, "emotionally appreciate its wrongfulness."73 One may expect prosecutors to emphasize the narrow sense of knowledge, whereas defense attorneys focus on the latter.

[ii] "Nature and Quality of the Act"

The phrase "nature and quality of the act" in the first prong of the M'Naghten test potentially is an exceedingly narrow concept. If D squeezes V's neck, believing that she is squeezing a lemon, she does not know "the nature and quality of her act." However, if she knows that she is squeezing the neck of a human being, but does not appreciate that her act is causing pain, she is sane insofar as the first prong of M'Naghten is concerned in jurisdictions that apply a narrow meaning of the word "knowledge," as discussed immediately above. Frequently, this prong is omitted from jury instructions or statutes because anyone who does not know what she is doing (e.g., cannot distinguish a neck from a lemon) will also "fail" the right-and-wrong test, the second prong of the insanity definition.74

[iii] "Right from Wrong"

A question exists whether the word "wrong" in the right-and-wrong prong refers to legal or moral wrongdoing. There is language in M'Naghten to support either interpretation. Lord Tindal, for example, stated early in the opinion that M'Naghten could be punished if he "knew . . . that he was acting contrary to law; by which expression we . . . mean the law of the land." Subsequently, however, he stated that if the jury were instructed "exclusively with reference to the law of the land it might tend to confound the jury by inducing them to believe that an actual knowledge of the law was essential." Rather, Lord Tindal stated, the question is whether M'Naghten knew that his "act was one which he ought not to do, and if the act was at the same time contrary to the law of the land, he is punishable." To the extent that the issue arises in insanity cases — that is, does "not knowing right from wrong" mean "legal wrong" or "moral wrong"?— United States law is sharply divided.75

The distinction will rarely affect the outcome of a trial: one who knows that her conduct is legally wrong presumably is aware that it is also morally wrong, and vice-versa.76 However, suppose that D, due to mental illness, believes that God has given her permission to kill V, an act that D knows violates the secular law. In view of God's permission, however, D presumably believes that it is morally proper to kill V. On these...

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