(redirected from Legal insanity)
Also found in: Dictionary, Thesaurus, Medical, Legal.
Related to Legal insanity: Insanity defense, insanity plea


mental disorder of such severity as to render its victim incapable of managing his affairs or of conforming to social standards. Today, the term insanity is used chiefly in criminal law, to denote mental aberrations or defects that may relieve a person from the legal consequences of his or her acts. The case of Daniel McNaughtan, who was found not guilty by reason of insanity after making an assassination attempt on British prime minister Robert Peel (1834), gave rise to the modern insanity defense used in many Western nations today. In the United States, the 1954 case of Durham v. the United States led to the establishment of new rules for testing defendants. Today, psychologists may perform tests to determine whether or not the defendant is mentally stable. Such tests try to ascertain whether or not a defendant can distinguish right from wrong, and whether or not he acted on an "irresistible impulse." John Hinckley's assassination attempt on Ronald Reagan (1981) became another landmark in the history of the insanity defense. The court's initial verdict of "not guilty by reason of insanity" generated public outcry and renewed interest in the verdict of "guilty but mentally ill," which is permissible in some states. This verdict allows defendants deemed mentally ill to be hospitalized but requires them to carry out a reasonable prison sentence as well. In 1983, the Supreme Court ruled it permissable to keep a mentally ill defendant hospitalized for a term longer than the maximum sentence for the crime with which the defendant was charged. Many have contended that the insanity defense is nothing more than a legal loophole, allowing serious criminals to escape imprisonment. In fact, the plea is rarely employed in the United States, and it is estimated that less than 1% of defendants have used it successfully. Recent years have seen the restrictions surrounding insanity defense considerably narrowed, with the sole criteria for a successful plea being the determination of whether or not the defendant knew he was breaking the law.


See R. Simon and D. Aaronson, The Insanity Defense (1988); R. Porter, A Social History of Madness: The World Through the Eyes of the Insane (1989).


Any mental disorder.
In forensic psychiatry, a mental disorder which prevents one from managing one's affairs, impairs one's ability to distinguish right from wrong, or renders one harmful to oneself or others.
Term previously used to indicate mental disorder; no longer used in medical contexts.


1. relatively permanent disorder of the mind; state or condition of being insane
2. Law a defect of reason as a result of mental illness, such that a defendant does not know what he or she is doing or that it is wrong
References in periodicals archive ?
competencies and to evaluate legal insanity and the negation of mens
defendant has a significant claim of legal insanity or needs expert
The irony is that until the 1980s, the M'Naghten rule was viewed as the stricter definition of legal insanity.
But the amount and type of psychopathology associated with them is not only fully consistent with the formation of mens rea, it is also only rarely sufficient to justify a colorable claim of legal insanity.
Unfortunately, there are no generic excusing criteria, but only discrete defenses, such as legal insanity.
After 1800, definitions of legal insanity in both England and the U.
None of the cognitive or control tests for legal insanity is
The relevance of mental disorder to legal insanity tests is
He doesn't get the benefit, under the law, of legal insanity.
At the time the Hinckley defense team persuaded the jury of his legal insanity.
17) In the United States, courts continue to evaluate postpartum depression defenses and other mental illnesses under the existing insanity defense, (18) The prevailing insanity defense test (19) applied across United States jurisdictions is extremely narrow and makes proving legal insanity exceptionally difficult for even the most severely postpartum psychotic women.
Brower finds the defendant: "insane (medically) and that the form of insanity if paranoia--As to his legal insanity, which as I understand it, is about synonymous with responsibility, I have some doubt--because of insufficient information as to family & personal history.

Full browser ?