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.
The M'Naghten rule is any variant of the 1840s jury instruction in a criminal case when there is a defence of insanity:
that every man is to be presumed to be sane, and ... that to establish a defence on the ground of insanity, it must be clearly proved that, at the time of the committing of 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 if he did know it, that he did not know he was doing what was wrong.
Insanity, madness, lunacy, and craziness are behaviors performed by certain abnormal mental or behavioral patterns. Insanity can manifest as violations of societal norms, including a person or persons becoming a danger to themselves or to other people. Conceptually, mental insanity also is associated with the biological phenomenon of contagion as in the case of copycat suicides. In contemporary usage, the term insanity is an informal, un-scientific term denoting "mental instability"; thus, the term insanity defense is the legal definition of mental instability. In medicine, the general term psychosis is used to include the presence of delusions and/or hallucinations in a patient; and psychiatric illness is "psychopathology", not mental insanity.
In criminal law, diminished responsibility is a potential defense by excuse by which defendants argue that although they broke the law, they should not be held fully criminally liable for doing so, as their mental functions were "diminished" or impaired.
In criminal law, automatism is a rarely used criminal defence. It is one of the mental condition defences that relate to the mental state of the defendant. Automatism can be seen variously as lack of voluntariness, lack of culpability (unconsciousness) or excuse. Automatism means that the defendant was not aware of his or her actions when making the particular movements that constituted the illegal act.
Actual innocence is a special standard of review in legal cases to prove that a charged defendant did not commit the crimes that they were accused of, which is often applied by appellate courts to prevent a miscarriage of justice.
The Criminal Lunatics Act 1800 was an Act of the Parliament of Great Britain that required and established a set procedure for the indefinite detention of mentally ill offenders. It was passed through the House of Commons in direct reaction to the trial of James Hadfield, who attempted to assassinate King George III.
Ford v. Wainwright, 477 U.S. 399 (1986), was a landmark U.S. Supreme Court case that upheld the common law rule that the insane cannot be executed; therefore the petitioner is entitled to a competency evaluation and to an evidentiary hearing in court on the question of their competency to be executed.
In the United States criminal justice system, a competency evaluation is an assessment of the ability of a defendant to understand and rationally participate in a court process.
In criminal law, a mitigating factor, also known as an extenuating circumstance, is any information or evidence presented to the court regarding the defendant or the circumstances of the crime that might result in reduced charges or a lesser sentence. Unlike a legal defense, the presentation of mitigating factors will not result in the acquittal of a defendant. The opposite of a mitigating factor is an aggravating factor.
Bigby v. Dretke 402 F.3d 551, the U.S. Court of Appeals for the Fifth Circuit heard a case appealed from the United States District Court for the Northern District of Texas on the issue of the instructions given to a jury in death penalty sentencing. The decision took into account the recent United States Supreme Court decisions concerning the relevance of mitigating evidence in sentencing, as in Penry v. Lynaugh.
Settled insanity is defined as a permanent or "settled" condition caused by long-term substance abuse and differs from the temporary state of intoxication. In some United States jurisdictions "settled insanity" can be used as a basis for an insanity defense, even though voluntary intoxication cannot, if the "settled insanity" negates one of the required elements of the crime such as malice aforethought. However, U.S. federal and state courts have differed in their interpretations of when the use of "settled insanity" is acceptable as an insanity defense and also over what is included in the concept of "settled insanity".
In the field of criminal law, there are a variety of conditions that will tend to negate elements of a crime, known as defenses. The label may be apt in jurisdictions where the accused may be assigned some burden before a tribunal. However, in many jurisdictions, the entire burden to prove a crime is on the prosecution, which also must prove the absence of these defenses, where implicated. In other words, in many jurisdictions the absence of these so-called defenses is treated as an element of the crime. So-called defenses may provide partial or total refuge from punishment.
Jones v. United States, 463 U.S. 354 (1983), is a United States Supreme Court case in which the court, for the first time, addressed whether the due process requirement of the Fourteenth Amendment allows defendants, who were found not guilty by reason of insanity (NGRI) of a misdemeanor crime, to be involuntarily confined to a mental institution until such times as they are no longer a danger to themselves or others with few other criteria or procedures limiting the actions of the state.
Insanity in English law is a defence to criminal charges based on the idea that the defendant was unable to understand what he was doing, or, that he was unable to understand that what he was doing was wrong.
United States federal laws governing offenders with mental diseases or defects provide for the evaluation and handling of defendants who are suspected of having mental diseases or defects. The laws were completely revamped by the Insanity Defense Reform Act in the wake of the John Hinckley Jr. verdict.
Criminal law is a system of laws that is connected with crimes and punishments of an individual who commits crimes. In comparison, civil law is where the case argues their issues with one entity to another entity with support of the law. Crimes can vary in definition by jurisdiction but the basis for a crime are fairly consistent regardless.
The Assistance of Counsel Clause of the Sixth Amendment to the United States Constitution provides: "In all criminal prosecutions, the accused shall enjoy the right...to have the Assistance of Counsel for his defence."
Hendershott v. People, Supreme Court of Colorado, 653 P.2d. 385 (1982), is a criminal case that a defendant who was not excused by being legally insane, might still be exculpated because he lacked a guilty mind due to a mental disease.
Kahler v. Kansas, 589 U.S. ___ (2020), is a case of the United States Supreme Court in which the justices ruled that the Eighth and Fourteenth Amendments of the United States Constitution do not require that states adopt the insanity defense in criminal cases that are based on the defendant's ability to recognize right from wrong. It was argued on October 7, 2019 and decided on March 23, 2020.
