Insanity

A defense based on the idea that a person allegedly accused of a crime cannot be held responsible for it if unaware of the implications of his or her actions. For example, the U.S. legal system requires that both the actus reus, that is the “guilty act,” proven beyond a reasonable doubt, and the mens rea, the “guilty mind,” (i.e., criminal intent) have to be established to prove criminal liability. Thus, if a person is unaware of what he or she is doing, the mens rea cannot be established. A defendant who is found not criminally responsible is judged NGRI, “not guilty by reason of insanity,” and may consequently be committed to a psychiatric hospital (Wrightsman & Fulero, 2005). Such defendants remain in psychiatric care for the duration they are evaluated; moreover, contrary to popular belief, they often end up confined in secure psychiatric hospitals for a longer period of time than they would have served in prison if convicted.

There is no uniform definition for insanity, and states vary with regard to their definitions of insanity; some states do not permit an insanity defense at all. Approximately half of the U.S. states continue to use the M'Naghten Rule, also known as the McNaughton standard. According to the M'Naghten Rule, a defendant can be found insane if he or she suffers from a “defect of reason or mind” and therefore did not understand the “nature and quality of the act he was doing” or did not understand the wrongfulness of the act (Wrightsman & Fulero, 2005). Due to criticism, the M'Naghten Rule was in some states replaced by the Durham test, only to be replaced by the ALI (American Legal Institute) standard (except for New Hampshire). The ALI standard was, at least initially, thought to be an improvement over M'Naghten, as it includes both a cognitive and a volitional prong. While the cognitive prong focuses on the defendant not being able to “appreciate the wrongfulness” of the act, the volitional prong focuses on the defendant not being able to “conform his or her conduct” (Wrightsman & Fulero, 2005) or, in other words, maintain control over his or her behavior. The ALI standard is now used in 21 U.S. states. For more information, see Wrightsman and Fulero (2005).