insanity defense

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Related to Mental disease or defect: Plea of temporary insanity

defense

 [de-fens´]
behavior directed to protection of the individual from injury.
character defense any character trait, e.g., a mannerism, attitude, or affectation, which serves as a defense mechanism.
insanity defense a legal concept that a person cannot be convicted of a crime if he lacked criminal responsibility by reason of insanity at the time of commission of the crime.
defense mechanism in psychology, an unconscious mental process or coping pattern that lessens the anxiety associated with a situation or internal conflict and protects the person from mental discomfort. In the theory of psychoanalysis, the ego, following the reality principle, conforms to the demands of the outside world, but the id (repressed unconscious), following the pleasure principle, pursues immediate gratification of desires and reduction of psychic tension. The superego (conscience or morality) may take either side. Defense mechanisms develop in order to control impulses or feelings that lead to inner conflicts, to reach compromises between conflicting impulses, and to reduce inner tensions. They help to manage or avoid anxiety, aggression, hostility, resentment, and frustration. Defense mechanisms are not pathological in themselves; they can be a means of dealing with unbearable situations. Among the most common defense mechanisms are denial, displacement, identification, projection, rationalization, reaction-formation, repression, and sublimation.
defense reaction a mental reaction that shuts out from consciousness ideas not acceptable to the ego. See also defense mechanism.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

in·san·i·ty de·fense

in forensic psychiatry, the use in the courtroom of insanity as a mitigating factor in the defense of an accused on trial for a serious criminal offense. See: criminal insanity.
Farlex Partner Medical Dictionary © Farlex 2012

insanity defense

Forensic psychiatry A legal defense that a person cannot be convicted of a crime if he lacked criminal responsibility by reason of insanity–a term defined as a matter of law; the premise is that where there is no mens rea because of insanity, there is no criminal responsibility. See American Law Institute Formulation, Durham Rule, Irresistible impulse test, Long Island Rail Road massacre, M'Naughton Rule. Cf 'Black rage' defense, Television intoxication, 'Twinkie' defense.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

insanity defense

In legal and forensic medicine, the premise that an insane person who commits a crime is not legally responsible for that act.
Medical Dictionary, © 2009 Farlex and Partners
References in periodicals archive ?
mental disease or defect that prevented the person from forming a
offense, the defendant, as the product of a mental disease or defect,
but care should be taken not to confuse such mental disease or defect
leaving only the question whether mental disease or defect left
(85) For example, in the Alabama insanity defense statute, abnormalities manifested only by repeated criminal or otherwise antisocial conduct are not included within the definition of "severe mental disease or defect." (86)
(67) When viewing the elements of a crime and the application of the insanity defense in this way, it is possible to imagine a situation where a defendant can have a severe mental disease or defect yet still have the ability to discern whether or not his conduct is right or wrong, legal or illegal.
Under Alabama law, a defendant can have a mental disease or defect, yet still have the ability to form mens rea or intent.
Mental disease or defect does not include disorders that result from acute voluntary intoxication or withdrawal from alcohol or drugs, character defects, psychosexual disorders or impulse control disorders.