M’Naghten Insanity Defense

The M’Naghten insanity defense, also called the right-wrong test, is the most common insanity defense in the United States. It is also the oldest and was created in England in 1843. The defense is named after Daniel M’Naghten. M’Naghten was under the paranoid delusion that the Prime Minister of England, Sir Robert Peel, was trying to kill him. When he tried to shoot Sir Peel from behind, he inadvertently shot Sir Peel’s Secretary, Edward Drummond, who thereafter died. M’Naghten was put on trial for murder and, to the shock of the nation, the jury found him not guilty by reason of insanity (Queen v. M’Naghten, 2010). After a public outcry at this verdict, the British House of Lords developed a test for insanity that remains relatively intact today.

The M’Naghten insanity defense is cognitive and focuses on the defendant’s awareness, rather than the ability to control conduct. The defense requires two elements. First, the defendant must be suffering from a mental defect at the time he or she commits the criminal act. The mental defect can be called a “defect of reason” or a “disease of the mind,” depending on the jurisdiction (Iowa Code, 2010). Second, the trier of fact must find that because of the mental defect, the defendant did not know either the nature and quality of the criminal act or that the act was wrong.

The terms “defect of reason” and “disease of the mind” can be defined in different ways, but in general, the defendant must be cognitively impaired to the level of not knowing the nature and quality of the criminal act, or that the act is wrong. Some common examples of mental defects and diseases are psychosis, schizophrenia, and paranoia.

Jurisdictions vary as to the level of awareness the defendant must possess. Some jurisdictions use the term “know,” or “understand,” (Cal. Penal Code, 2010) while others use the term “appreciate” (Ala. Code, 2010). If know or understand is the standard, the trier of fact must ascertain a basic level of awareness under the attendant circumstances. If appreciate is the standard, the trier of fact must analyze the defendant’s emotional state, and evidence of the defendant’s character or personality may be relevant and admissible.

A defendant does not know the nature and quality of a criminal act if the defendant is completely oblivious to what he or she is doing. This is quite rare, so most defendants claiming insanity choose to assert that they did not know their act was wrong. However, jurisdictions differ as to the meaning of “wrong.” Some jurisdictions define wrong as “legally wrong,” meaning the defendant must be unaware that the act is against the law (State v. Crenshaw, 2010). Others define wrong as “legally and morally wrong,” meaning the defendant must also be unaware that the act is condemned by society (State v. Skaggs, 2010). Generally, the only instance where the defendant must be “morally wrong,” standing alone, is when the defendant claims that the conduct was performed at the command of God, which is called the deific defense (State v. Worlock, 2010). Whether the standard is legally wrong or morally wrong, if there is any evidence of a cover-up or an attempt to hide or escape, it is apparent that the defendant knew the difference between right and wrong, defeating the claim of insanity under M’Naghten.

Irresistible Impulse Insanity Defense

Another variation of the insanity defense is the irresistible impulse defense. This defense has lost popularity over the years and is rejected by most of the states and the federal government (18 U.S.C., 2010). In some cases, the irresistible impulse insanity defense is easier to prove than the M’Naghten insanity defense, resulting in the acquittal of more mentally disturbed defendants.

The irresistible impulse insanity defense generally supplements M’Naghten, so the focus is on the defendant’s awareness (cognitive) and the defendant’s will (ability to control conduct). In jurisdictions that recognize the irresistible impulse insanity defense, the first element is the same as M’Naghten; the defendant must suffer from a mental defect or disease of the mind. However, the second element adds the concept of volition, or free choice. If the defendant cannot control his or her conduct because of the mental defect or disease, the defendant’s conduct is excused even if the defendant understands that the conduct is wrong (State v. White, 2010). This is a softer stance than M’Naghten, which does not exonerate a defendant who is aware conduct is wrong. The challenge for the trier of fact in an irresistible impulse jurisdiction is distinguishing between conduct that can be controlled and conduct that cannot.

The Substantial Capacity Test

The substantial capacity test is the insanity defense created by the Model Penal Code. The Model Penal Code was completed in 1962. By 1980, approximately half of the states and the federal government adopted the substantial capacity test (also called the Model Penal Code or ALI defense) (Rolf, C. A., 2010). However, in 1982, John Hinckley successfully claimed insanity using the substantial capacity test in his federal trial for the attempted murder of then-President Ronald Reagan. Public indignation at this not-guilty verdict caused many states and the federal government to switch from the substantial capacity test to the more inflexible M’Naghten standard (18 U.S.C., 2010). In addition, jurisdictions that switched to M’Naghten also shifted the burden of proving insanity to the defendant (Rolf, C. A., 2010). The defendant’s burden of proof for the insanity defense is discussed shortly.

The substantial capacity test is as follows: “A person is not responsible for criminal conduct if at the time of such conduct as a result of mental disease or defect he lacks substantial capacity either to appreciate the criminality [wrongfulness] of his conduct or to conform his conduct to the requirements of law” (Model Penal Code § 4.01(1)). The defense has two elements. The first element requires the defendant to have a mental disease or defect, like the M’Naghten and irresistible impulse insanity defenses. The second element combines the cognitive standard with volitional, like the irresistible impulse insanity defense supplementing the M’Naghten insanity defense.

In general, it is easier to establish insanity under the substantial capacity test because both the cognitive and volitional requirements are scaled down to more flexible standards. Unlike the M’Naghten insanity defense, the substantial capacity test relaxes the requirement for complete inability to understand or know the difference between right and wrong. Instead, the defendant must lack substantial, not total, capacity. The “wrong” in the substantial capacity test is “criminality,” which is a legal rather than moral wrong. In addition, unlike the irresistible impulse insanity defense, the defendant must lack substantial, not total, ability to conform conduct to the requirements of the law. Another difference in the substantial capacity test is the use of the word “appreciate” rather than “know.” As stated previously, appreciate incorporates an emotional quality, which means that evidence of the defendant’s character or personality is relevant and most likely admissible to support the defense.

The Durham Insanity Defense

The Durham insanity defense is used only in New Hampshire and has been the established insanity defense in New Hampshire since the late 1800s. The Durham defense, also called the Durham rule or the product test, was adopted by the Circuit Court of Appeals for the District of Columbia in the case of Durham v. U.S., 214 F.2d 862 (1954). The defense set forth in that case is as follows: “[A]n accused is not criminally responsible if his unlawful act was the product of mental disease or mental defect” (Durham v. U.S., 2010). However, the court failed to give definitions for product, mental disease, or mental defect. Thus the Durham insanity defense is extremely difficult to apply, and the D.C. Circuit rejected it in 1972 in the case of U.S. v. Brawner, 471 F.2d 969 (1972), which was later superseded by federal statute (18 U.S.C., 2010).

In general, the Durham insanity defense relies on ordinary principles of proximate causation. The defense has two elements. First, the defendant must have a mental disease or defect. Although these terms are not specifically defined in the Durham case, the language of the judicial opinion indicates an attempt to rely more on objective, psychological standards, rather than focusing on the defendant’s subjective cognition. The second element has to do with causation. If the criminal conduct is “caused” by the mental disease or defect, then the conduct should be excused under the circumstances.

Proving Insanity

There is generally a presumption that criminal defendants are sane, just as there is a presumption that they are innocent. Therefore, at a minimum, a defendant claiming insanity must produce evidence that rebuts this presumption. Some states require the prosecution to thereafter prove sanity beyond a reasonable doubt or to a preponderance of evidence (Elkins, J.R., and students, 2010).

Post-Hinckley, many states have converted the insanity defense into an affirmative defense. Thus as discussed in Chapter 6 “Criminal Defenses, Part 1”, the defendant may also have the burden of persuading the trier of fact that he or she is insane to a preponderance of evidence (New Jersey Jury Instruction on Insanity, 2010). The federal government and some other states require the defendant to prove insanity by clear and convincing evidence, which is a higher standard than preponderance of evidence (Tenn. Code Ann., 2010).

Diminished Capacity

A claim of diminished capacity differs from the insanity defense. Diminished capacity is an imperfect failure of proof defense recognized in a minority of jurisdictions. Diminished capacity could reduce a first-degree murder charge to second-degree murder or manslaughter if the defendant lacks the mental capacity to form the appropriate criminal intent for first-degree murder.

In California, diminished capacity was abolished as an affirmative defense after San Francisco Supervisor Dan White used it successfully in his trial for the murder of fellow Supervisor Harvey Milk. A jury convicted White of voluntary manslaughter rather than first-degree premeditated murder after reviewing evidence that proved his diet of junk food (Twinkies) created a chemical imbalance in his brain. In the aftermath of this highly publicized trial, California passed legislation eliminating the diminished capacity defense and limiting the admissibility of evidence of diminished capacity only to sentencing proceedings (Cal. Penal Code, 2010).

Similar to diminished capacity is the syndrome defense. A syndrome that negates the requisite intent for the crime could function as a failure of proof defense in a minority of jurisdictions. Some common examples of syndromes the American Psychiatric Association recognizes in the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV), are antisocial personality disorder, posttraumatic stress disorder, and intermittent explosive disorder. Some common examples of syndromes identified but not recognized in DSM-IV are battered woman or battered wife syndrome (discussed in Chapter 6 “Criminal Defenses, Part 1”) and caffeine withdrawal. Although successful use of the syndrome defense is rare, at least one case has excused a defendant’s drunken driving and assault and battery against a police officer because of premenstrual syndrome (PMS) (Baltimore.com, 2011).

Mental Competence to Stand Trial

The insanity defense is different from mental competence to stand trial. The insanity defense pertains to the defendant’s mental state when he or she commits the crime. If the insanity defense is successful, it exonerates the defendant from guilt. Mental competence to stand trial is analyzed at the time the trial is to take place. If the defendant is mentally incompetent to stand trial, the trial is delayed until the defendant regains competency. Although a detailed discussion of mental competence to stand trial is beyond the scope of this book, in general, a criminal defendant must be able to understand the charges against him or her, and be able to assist in his or her defense. As the Model Penal Code provides, “[n]o person who as a result of mental disease or defect lacks capacity to understand the proceedings against him or to assist in his own defense shall be tried, convicted or sentenced for the commission of an offense so long as such incapacity endures” (Model Penal Code § 4.04). A defendant who is mentally incompetent at the time of trial is subject to mental health treatment or even involuntary medication until competence is regained.

Guilty but Mentally Ill

Post-Hinckley, some states adopted the guilty but mentally ill verdict. A defendant who is found guilty but mentally ill is not acquitted but punished and treated for mental health simultaneously while in prison. Typically, the guilty but mentally ill verdict is available only when the defendant fails to prove legal insanity, and requires the defendant to prove mental illness at the time of the crime to a preponderance of evidence (725 ILCS, 2010).

Disposition of the Legally Insane

The not guilty by reason of insanity verdict means that the defendant is absolved from criminal responsibility and devoid of any criminal record for the offense. However, it does not mean that the defendant is free to return to society.

In several states and federally, a defendant who is found not guilty by reason of insanity is automatically committed to a treatment facility until there is a determination that mental health has been restored (18 U.S.C., 2010). This is also the Model Penal Code approach. As the Model Penal Code states in § 4.08(1), “[w]hen a defendant is acquitted on the ground of mental disease or defect excluding responsibility, the Court shall order him to be committed to the custody of the Commissioner of Mental Hygiene [Public Health] to be placed in an appropriate institution for custody, care and treatment.”

Other states have a hearing on sanity after the judgment or verdict of not guilty by reason of insanity is returned. If the defendant is deemed mentally competent at the hearing, he or she is released. If the defendant is found mentally ill at the hearing, he or she is committed to the appropriate treatment facility (Ohio Rev. Code Ann., 2010).

Temporary Insanity

Many states also recognize temporary insanity, which does not differ in analysis from permanent insanity except for the duration of the mental illness (Malo, A., Barach, M. P., & Levin, J. A., 2010). In a state that recognizes temporary insanity, the elements of the state’s insanity defense, either M’Naghten, irresistible impulse, substantial capacity, or Durham, must be present at the time the crime was committed. If the defendant is found not guilty by reason of insanity for the criminal offense, but regains mental competence at the time of prosecution, the defendant is released after the verdict is rendered. The trial court will order release based on the commitment procedure discussed in Section 7.1.9 “Disposition of the Legally Insane”.