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.
Insanity, madness, lunacy, and craziness are behaviors caused 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 American jurisprudence, an excuse is a defense to criminal charges that is a distinct from an exculpation. Justification and excuse are different defenses in a criminal case. Exculpation is a related concept which reduces or extinguishes a person's culpability, such as their liability to pay compensation to the victim of a tort in the civil law.
In criminal law, the intoxication defense is a defense by which a defendant may claim diminished responsibility on the basis of substance intoxication. Where a crime requires a certain mental state to break the law, those under the influence of an intoxicating substance may be considered to have reduced liability for their actions. With regard to punishment, intoxication may be a mitigating factor that decreases a prison or jail sentence. Numerous factors affect the applicability of the defense.
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.
The abuse defense is a criminal law defense in which the defendant argues that a prior history of abuse justifies violent retaliation. While the term most often refers to instances of child abuse or sexual assault, it also refers more generally to any attempt by the defense to use a syndrome or societal condition to deflect responsibility away from the defendant. Sometimes the concept is referred to as the abuse excuse, in particular by the critics of the idea that guilty people may use past victimization to diminish the responsibility for their crimes.
Forensic psychiatry is a subspeciality of psychiatry and is related to criminology. It encompasses the interface between law and psychiatry. According to the American Academy of Psychiatry and the Law, it is defined as "a subspecialty of psychiatry in which scientific and clinical expertise is applied in legal contexts involving civil, criminal, correctional, regulatory, or legislative matters, and in specialized clinical consultations in areas such as risk assessment or employment." A forensic psychiatrist provides services – such as determination of competency to stand trial – to a court of law to facilitate the adjudicative process and provide treatment, such as medications and psychotherapy, to criminals.
The United States Federal Sentencing Guidelines are rules published by the U.S. Sentencing Commission that set out a uniform policy for sentencing individuals and organizations convicted of felonies and serious misdemeanors in the United States federal courts system. The Guidelines do not apply to less serious misdemeanors or infractions.
Battered woman syndrome (BWS) is a pattern of signs and symptoms displayed by a woman who has suffered persistent intimate partner violence—psychological, physical, or sexual—from her male partner. It is classified in the ICD-9 as battered person syndrome, but is not in the DSM-5. It may be diagnosed as a subcategory of post-traumatic stress disorder (PTSD). Victims may exhibit a range of behaviors, including self-isolation, suicidal thoughts, and substance abuse, and signs of physical injury or illness, such as bruises, broken bones, or chronic fatigue.
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.
Emergency psychiatry is the clinical application of psychiatry in emergency settings. Conditions requiring psychiatric interventions may include attempted suicide, substance abuse, depression, psychosis, violence or other rapid changes in behavior.
In English law, diminished responsibility is one of the partial defenses that reduce the offense from murder to manslaughter if successful. This allows the judge sentencing discretion, e.g. to impose a hospital order under section 37 of the Mental Health Act 1983 to ensure treatment rather than punishment in appropriate cases. Thus, when the actus reus of death is accompanied by an objective or constructive version of mens rea, the subjective evidence that the defendant did intend to kill or cause grievous bodily harm because of a mental incapacity will partially excuse his conduct. Under s.2(2) of the Homicide Act 1957 the burden of proof is on the defendant to the balance of probabilities. The M'Naghten Rules lack a volitional limb of "irresistible impulse"; diminished responsibility is the volitional mental condition defense in English criminal law.
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.
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 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.
An ultimate issue in criminal law is a legal issue at stake in the prosecution of a crime for which an expert witness is providing testimony.
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 criminal law of the United States is a manifold system of laws and practices that connects crimes and consequences. In comparison, civil law addresses non-criminal disputes. The system varies considerably by jurisdiction, but conforms to the US Constitution. Generally there are two systems of criminal law to which a person maybe subject; the most frequent is state criminal law, and the other is federal law.
Manslaughter is a crime in the United States. Definitions can vary among jurisdictions, but manslaughter is invariably the act of causing the death of another person in a manner less culpable than murder. Three types of unlawful killings constitute manslaughter. First, there is voluntary manslaughter which is an intentional homicide committed in "sudden heat of passion" as the result of adequate provocation. Second, there is the form of involuntary manslaughter which is an unintentional homicide that was committed in a criminally negligent manner. Finally, there is the form of involuntary manslaughter which is an unintentional homicide that occurred during the commission or attempted commission of an unlawful act which does not amount to a felony.