Insanity defense
The insanity defense, also known as the mental disorder defense, is an affirmative defense by excuse in a criminal case, arguing that the defendant is not responsible for their actions due to a psychiatric disease at the time of the criminal act. This is contrasted with an excuse of provocation, in which the defendant is responsible, but the responsibility is lessened due to a temporary mental state. It is also contrasted with the justification of self defense or with the mitigation of imperfect self-defense. The insanity defense is also contrasted with a finding that a defendant cannot stand trial in a criminal case because a mental disease prevents them from effectively assisting counsel, from a civil finding in trusts and estates where a will is nullified because it was made when a mental disorder prevented a testator from recognizing the natural objects of their bounty, and from involuntary civil commitment to a mental institution, when anyone is found to be gravely disabled or to be a danger to themself or to others.
Legal definitions of insanity or mental disorder are varied, and include the M'Naghten Rule, the Durham rule, the 1953 British Royal Commission on Capital Punishment report, the ALI rule, and other provisions, often relating to a lack of mens rea. In the criminal laws of Australia and Canada, statutory legislation enshrines the M'Naghten Rules, with the terms "defense of mental disorder", "defense of mental illness", or "not criminally responsible by reason of mental disorder" employed. Being incapable of distinguishing right from wrong is one basis for being found to be legally insane as a criminal defense. It originated in the M'Naghten Rule, and has been reinterpreted and modernized through more recent cases, such as People v. Serravo.
In the United Kingdom, Ireland, and the United States, use of the defense is rare. Mitigating factors, including things not eligible for the insanity defense such as intoxication and partial defenses such as diminished capacity and provocation, are used more frequently.
The defense is based on evaluations by forensic mental health professionals with the appropriate test according to the jurisdiction. Their testimony guides the jury, but they are not allowed to testify to the accused's criminal responsibility, as this is a matter for the jury to decide. Similarly, mental health practitioners are restrained from making a judgment on the "ultimate issue"—whether the defendant is insane.
Some jurisdictions require the evaluation to address the defendant's ability to control their behavior at the time of the offense. A defendant claiming the defense is pleading "not guilty by reason of insanity" or "guilty but insane or mentally ill" in some jurisdictions which, if successful, may result in the defendant being committed to a psychiatric facility for an indeterminate period.
Non compos mentis
Non compos mentis is a legal term meaning "not of sound mind". Non compos mentis derives from the Latin non meaning "not", compos meaning "control" or "command", and mentis, meaning "of mind". It is the direct opposite of Compos mentis.Although typically used in law, this term can also be used metaphorically or figuratively; e.g. when one is in a confused state, intoxicated, or not of sound mind. The term may be applied when a determination of competency needs to be made by a physician for purposes of obtaining informed consent for treatments and, if necessary, assigning a surrogate to make health care decisions. While the proper sphere for this determination is in a court of law, this is practically, and most frequently, made by physicians in the clinical setting.
In English law, the rule of non compos mentis was most commonly used when the defendant invoked religious or magical explanations for behaviour. An example of religious circumstances which prevent an individual from being guilty due to mental defect can be found in Catholic Canon Law.
History
The concept of defense by insanity has existed since ancient Greece and Rome. During the Roman and Greek eras, insanity was used as a way to help provide a defense for those with mental disorders. However, in colonial America a delusional Dorothy Talbye was hanged in 1638 for murdering her daughter, as at the time Massachusetts's common law made no distinction between insanity and criminal behavior. Edward II, under English common law, declared that a person was insane if their mental capacity was no more than that of a "wild beast". The first complete transcript of an insanity trial dates to 1724. It is likely that the insane, like those under 14, were spared trial by ordeal. When that was replaced by trial by jury, members were expected to find the insane guilty but then to refer the case to the king for a royal pardon. From 1500 onwards, juries could acquit the insane, and detention required a separate civil procedure. The Criminal Lunatics Act 1800, passed with retrospective effect following the acquittal of James Hadfield, mandated detention at the regent's pleasure even for those who, although insane at the time of the offence, were now sane.The M'Naghten Rules of 1843 were not a codification or definition of insanity but rather the responses of a panel of judges to hypothetical questions posed by Parliament in the wake of Daniel M'Naghten's acquittal for the homicide of Edward Drummond, whom he mistook for British Prime Minister Robert Peel. The rules define the defense as "at the time of committing the act the party accused was labouring under such a defect of reason, from disease of the mind, as not to know the nature and quality of the act he was doing, or as not to know that what he was doing was wrong." The key is that the defendant could not appreciate the nature of their actions during the commission of the crime.
In Ford v. Wainwright 477 U.S. 399, the US Supreme Court upheld the common law rule that the insane cannot be executed. It further stated that a person under the death penalty is entitled to a competency evaluation and to an evidentiary hearing in court on the question of their competency to be executed.
In Wainwright v. Greenfield, the Court ruled that it was fundamentally unfair for the prosecutor to comment during the court proceedings on the petitioner's silence invoked as a result of a Miranda warning. The prosecutor had argued that the respondent's silence after receiving Miranda warnings was evidence of his sanity.
In 2006, the US Supreme Court decided Clark v. Arizona, upholding Arizona's restrictions on the insanity defense.
Kahler v. Kansas, 589 U.S. ___, is a case in which the US Supreme Court justices ruled that the Eighth and the Fourteenth Amendments of the US Constitution do not require states to adopt the insanity defense in criminal cases that are based on the defendant's ability to recognize right from wrong.
Application
The defense of insanity takes different guises in different jurisdictions, and there are differences between legal systems with regard to the availability, definition and burden of proof, as well as the role of judges, juries and medical experts. In jurisdictions where there are jury trials, it is common for the decision about the sanity of an accused to be determined by the jury.Incompetency and mental illness
An important distinction to be made is the difference between competency and criminal responsibility.- The issue of competency is whether a defendant is able to adequately assist their attorney in preparing a defense, make informed decisions about trial strategy and whether to plead guilty, accept a plea agreement or plead not guilty. This issue is dealt with in UK law as "fitness to plead".
In the United States, a trial in which the insanity defense is invoked typically involves the testimony of psychiatrists or psychologists who will, as expert witnesses, present opinions on the defendant's state of mind at the time of the offense.
Therefore, a person whose mental disorder is not in dispute is determined to be sane if the court decides that despite a "mental illness" the defendant was responsible for the acts committed and will be treated in court as a normal defendant. If the person has a mental illness and it is determined that the mental illness interfered with the person's ability to determine right from wrong and if the person is willing to plead guilty or is proven guilty in a court of law, some jurisdictions have an alternative option known as either a Guilty but Mentally Ill or a Guilty but Insane verdict. The GBMI verdict is available as an alternative to, rather than in lieu of, a "not guilty by reason of insanity" verdict. Michigan was the first state to create a GBMI verdict, after two prisoners released after being found NGRI committed violent crimes within a year of release, one raping two women and the other killing his wife.
Temporary insanity
The notion of temporary insanity argues that a defendant was insane during the commission of a crime, but they later regained their sanity after the criminal act was carried out. This legal defense developed in the 19th century and became especially associated with the defense of individuals committing crimes of passion. The defense was first successfully used by U.S. Congressman Daniel Sickles of New York in 1859 after he had killed his wife's lover, Philip Barton Key II. The temporary insanity defense was unsuccessfully pleaded by Charles J. Guiteau who assassinated president James A. Garfield in 1881.Mitigating factors and diminished capacity
The United States Supreme Court and the United States Court of Appeals for the Fifth Circuit have been clear in their decisions that jury instructions in death penalty cases that do not ask about mitigating factors regarding the defendant's mental health violate the defendant's Eighth Amendment rights, saying that the jury is to be instructed to consider mitigating factors when answering unrelated questions. This ruling suggests specific explanations to the jury are necessary to weigh mitigating factors.Diminished responsibility or diminished capacity can be employed as a mitigating factor or partial defense to crimes. In the United States, diminished capacity is applicable to more circumstances than the insanity defense. The Homicide Act 1957 is the statutory basis for the defense of diminished responsibility in England and Wales, whereas in Scotland it is a product of case law. The number of findings of diminished responsibility has been matched by a fall in unfitness to plead and insanity findings. A plea of diminished capacity is different from a plea of insanity in that "reason of insanity" is a full defense while "diminished capacity" is merely a plea to a lesser crime.