The insanity defense refers to that branch of the concept of insanity which defines the extent to which men accused of crimes may be relieved of criminal responsibility by virtue of mental disease. The terms of such a defense are to be found in the instructions presented by the trial judge to the jury at the close of a case. These instructions can be drawn from any of several rules used in the determination of mental illness. The final determination of mental illness rests solely on the jury who uses information drawn from the testimony of “expert” witnesses, usually professionals in the field of psychology. The net result of such a determination places an individual accordingly, be it placement in a mental facility, incarceration, or outright release. Due to these aforementioned factors, there are several problems raised by the existence of the insanity defense. Problems such as the actual possibility of determining mental illness, justifiable placement of judged “mentally ill” offenders, and the overall usefulness of such a defense. In all, I believe that these problems, as well as others which will be mentioned later, lead us to the conclusion that the insanity defense is useless and should be abolished entirely.
Insanity is a legal, not a medical definition. Therefore, mental illness and insanity are not synonymous: only some mental illness constitutes insanity. Insanity, however, includes not only mental illness but also mental deficiencies. Due to this, there are problems in exactly how to apply a medical theory to a legal matter (Herman, 1983;128). The legal concepts of mental illness and insanity raise questions in a conflict between what are termed legalistic criminology and scientific criminology: mens rea, punishment v. treatment, responsibility, and prisons v. hospitals. This debate seesaws to and fro amidst a grey area between law and science. The major difficulty with a theory such as mental illness is that it is just that, a theory. To scientists theories are a way of life, but applied to the concept of law theories become somewhat dangerous. By applying a loose theory such as mental illness to law we are in essence throwing the proverbial “monkey wrench” into the wheels of justice.
TESTING FOR INSANITY
At the center of the legal use of insanity lies the mens rea. Every crime involves a physical act, or actus reus, and a mental act, or mens rea, the non-physical cause of behavior. The mens rea is the mental element required for a crime, and if absent excuses the defendant from criminal responsibility and punishment (Jeffery, 1985;49). The difficulty here lies in analyzing the mens rea. In order to do this lawyers apply one of several rules used by psychologists. These rules range from the Irresistible Impulse Test to the M’Naghten Rule. Each of these rules approach mental illness/capacity in a different way and in my opinion each falls short of actual proof. I will discuss each in detail.
The M’Naghten Rule The M’Naghten Rule, also known as the right-wrong test, arose in 1843 during the trial of Daniel M’Naghten who argued that he was not criminally responsible for his actions because he suffered from delusions at the time of the killing. The M’Naghten Rule reads: A defendant may be excused from criminal responsibility if at the time of the commission of the act the party accused was laboring under such a defect of reason, from a disease of the mind, as not to know the nature and the quality of the act he was doing, or if he did know it, that he did not know that he was doing what was wrong. Thus, according to the rule, a person is basically insane if he or she is unable to distinguish between right and wrong as a result of some mental disability.
Criticism of the M’Naghten Rule has come from both legal and medical professions. Many criticize that the test is unsound in its view of human psychology. Psychiatry, it is argued, views the human personality as an integrated entity, not divisible into separate compartments of reason, emotion, or volition (Herman, 1983;138). Additionally, the test is criticized for defining responsibility solely in terms of cognition. While cognitive symptoms may reveal disorder,