Editing Insanity defense (section)

{{Short description|Legal concept regarding a defendant's state of mind}}
{{Use American English|date=August 2020}}
{{Criminal defenses}}
The '''insanity defense''', also known as the '''mental disorder defense''', is an affirmative [[Defense (legal)|defense]] by [[excuse]] in a [[criminal case]], arguing that the [[defendant]] is not responsible for their actions due to a [[mental illness|psychiatric disease]] at the time of the criminal act. This is contrasted with an excuse of [[provocation (legal)|provocation]], in which the defendant is responsible, but the responsibility is lessened due to a temporary mental state.<ref name="CL">''Criminal Law - Cases and Materials'', 7th ed. 2012, [[Wolters Kluwer Law & Business]]; [[John Kaplan (law professor)|John Kaplan]], [[Robert Weisberg]], [[Guyora Binder]], {{ISBN|978-1-4548-0698-1}}, {{cite web |title=Criminal Law: Cases and Materials, 7th edition |url=https://law.stanford.edu/publications/criminal-law-cases-and-materials-7th-edition/ |url-status=live |archive-url=https://web.archive.org/web/20161007173248/https://law.stanford.edu/publications/criminal-law-cases-and-materials-7th-edition/ |archive-date=2016-10-07 |access-date=2018-05-29}}</ref>{{rp|613}} It is also contrasted with the [[Justification (jurisprudence)|justification]] of [[Self-defense|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 case|civil]] finding in [[Trust law|trusts]] and [[estate (law)|estate]]s 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.<ref name=CL/>{{rp|613}}

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]] (American Legal Institute Model Penal Code rule), and other provisions, often relating to a lack of ''[[mens rea]]'' ("guilty mind").<ref name=CL/>{{rp|613–635}}<ref name="Cornell1">{{cite web|title=The insanity defense and diminished capacity|url=https://www.law.cornell.edu/background/insane/insanity.html|work=Legal Information Institute: Federal Law|publisher=Cornell University Law School|access-date=19 December 2011|author=Legal Information Institute|url-status=live|archive-url=https://web.archive.org/web/20120102214102/http://www.law.cornell.edu/background/insane/insanity.html|archive-date=2 January 2012}}</ref> In the [[criminal law]]s 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]].<ref name="CL"/> It originated in the ''M'Naghten Rule'', and has been reinterpreted and modernized through more recent cases, such as ''[[People v. Serravo]]''.<ref name=CL/>{{rp|615–625}}

In the United Kingdom, Ireland, and the United States, use of the defense is rare.<ref name="Schmalleger">{{cite book|last=Schmalleger|first=Frank|title=Criminal Justice: A Brief Introduction|publisher=Prentice Hall|year=2001|isbn=0-13-088729-3|url=https://archive.org/details/criminaljustic2001schm}}</ref>  [[Mitigating factors]], including things not eligible for the insanity defense such as [[alcohol intoxication|intoxication]]<ref>American Psychiatric Association: The Insanity Defense: Position Statement. Washington, DC: APA Document Reference No. 820002, 1982</ref> and [[partial defense]]s such as  [[diminished capacity]] and [[Provocation (legal)|provocation]], are used more frequently.

The defense is based on evaluations by [[Forensic psychology|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.<ref name="shapirointer">{{cite book
|first=David L.
|last=Shapiro
|year=1991
|title=Forensic Psychological Assessment: An Integrative Approach
|publisher=Simon & Schuster
|location=Needham Heights, MA
|page=69
|isbn= 0-205-12521-2}}</ref>

Some jurisdictions require the evaluation to address the defendant's ability to control their behavior at the time of the offense (the volitional limb). A defendant claiming the defense is pleading "not guilty by reason of insanity" (NGRI) 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.