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(s) (pronounced, and sometimes spelled, McNaughton) is a legal test defining the defence of insanity that was formulated by the House of Lords in 1843. It is the established standard in UK criminal law. Versions have been adopted in some US states, currently or formerly, and other jurisdictions, either as case law or by statute. Its original wording is a proposed jury instruction:
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.
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.
Thomas Erskine, 1st Baron Erskine, was a British Whig lawyer and politician. He served as Lord High Chancellor of Great Britain between 1806 and 1807 in the Ministry of All the Talents.
Under the law of the United Kingdom, high treason is the crime of disloyalty to the Crown. Offences constituting high treason include plotting the murder of the sovereign; committing adultery with the sovereign's consort, with the sovereign's eldest unmarried daughter, or with the wife of the heir to the throne; levying war against the sovereign and adhering to the sovereign's enemies, giving them aid or comfort; and attempting to undermine the lawfully established line of succession. Several other crimes have historically been categorised as high treason, including counterfeiting money and being a Catholic priest.
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.
The Offences against the Person Act 1861 is an Act of the Parliament of the United Kingdom of Great Britain and Ireland. It consolidated provisions related to offences against the person from a number of earlier statutes into a single Act. For the most part these provisions were, according to the draftsman of the Act, incorporated with little or no variation in their phraseology. It is one of a group of Acts sometimes referred to as the Criminal Law Consolidation Acts 1861. It was passed with the object of simplifying the law. It is essentially a revised version of an earlier consolidation act, the Offences Against the Person Act 1828, incorporating subsequent statutes.
The criminal law of Canada is under the exclusive legislative jurisdiction of the Parliament of Canada. The power to enact criminal law is derived from section 91(27) of the Constitution Act, 1867. Most criminal laws have been codified in the Criminal Code, as well as the Controlled Drugs and Substances Act, Youth Criminal Justice Act and several other peripheral statutes.
Murder is an offence under the common law legal system of England and Wales. It is considered the most serious form of homicide, in which one person kills another with the intention to unlawfully cause either death or serious injury. The element of intentionality was originally termed malice aforethought, although it required neither malice nor premeditation. Baker states that many killings done with a high degree of subjective recklessness were treated as murder from the 12th century right through until the 1974 decision in DPP v Hyam.
James Hadfield or Hatfield attempted to assassinate George III of Great Britain in 1800 but was acquitted of attempted murder by reason of insanity.
The Treason Act 1695 is an Act of the Parliament of England which laid down rules of evidence and procedure in high treason trials. It was passed by the English Parliament but was extended to cover Scotland in 1708 and Ireland in 1821. Some of it is still in force today.
Clark v. Arizona, 548 U.S. 735 (2006), is a United States Supreme Court case in which the Court upheld the constitutionality of the insanity defense used by Arizona.
The Treason Act 1800 was an Act of the Parliament of the Kingdom of Great Britain. It assimilated the procedure on trials for treason and misprision of treason to the procedure on trials for murder in certain cases. It was passed as a result of an attempt on the life of George III by James Hadfield earlier that year. The Criminal Lunatics Act 1800 was passed at the same time.
In the law of England and Wales, fitness to plead is the capacity of a defendant in criminal proceedings to comprehend the course of those proceedings. The concept of fitness to plead also applies in Scots and Irish law. Its United States equivalent is competence to stand trial.
The Criminal Law Act 1967 is an act of the Parliament of the United Kingdom that made some major changes to English criminal law, as part of wider liberal reforms by the Labour government elected in 1966. Most of it is still in force.
English criminal law concerns offences, their prevention and the consequences, in England and Wales. Criminal conduct is considered to be a wrong against the whole of a community, rather than just the private individuals affected. The state, in addition to certain international organisations, has responsibility for crime prevention, for bringing the culprits to justice, and for dealing with convicted offenders. The police, the criminal courts and prisons are all publicly funded services, though the main focus of criminal law concerns the role of the courts, how they apply criminal statutes and common law, and why some forms of behaviour are considered criminal. The fundamentals of a crime are a guilty act and a guilty mental state. The traditional view is that moral culpability requires that a defendant should have recognised or intended that they were acting wrongly, although in modern regulation a large number of offences relating to road traffic, environmental damage, financial services and corporations, create strict liability that can be proven simply by the guilty act.
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.
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.
The Trial of Lunatics Act 1883 is an act of the Parliament of the United Kingdom, allowing the jury to return a verdict that the defendant was guilty, but insane at the time, and should be kept in custody as a "criminal lunatic". This act was passed at the request of Queen Victoria, who, the target of frequent attacks by mentally ill individuals, demanded that the verdict be changed from "not guilty" so as to act as a deterrent to other lunatics; the phrasing of "guilty of the act or omission charged, but insane so as not to be responsible, according to law, for his actions" remained in use until the Criminal Procedure (Insanity) Act 1964.
The Treason Act 1541 or the Consequences of Attainer for Treason Act 1541 was an Act of the Parliament of England passed in 1542. It provided for the trial and punishment of lunatics for high treason. The reason given for passing the Act was given by the Act itself, which stated "it is a thing almost impossible certainly to judge" whether a defendant's madness was real or feigned.
