0.25% of all cases.
When someone successfully uses the insanity plea then they would plead not guilty by reason of insanity
It applies only after this defense is successfully used to convince a jury that it was the main reason that the defendant committed the crime. It would be in the sentencing aspect of the trial that the judge must apply the apporpriate law(s).
Insanity defense and self defense
In an insanity defense, the defense must prove that the defendant is insane.
about 26% of all court cases
Alibi, insanity, duress, self-defense and entrapment.
The insanity defense is alright as long as it is not used in just any case situation involving a murder. An insanity defense may allow a defendant who is mentally competent and has no history of mental illness to fake a specific mental disorder like Dissociative Identity Disorder (like in a Law & Order SVU episode titled "Alternate") and use it as a way to plead "not guilty by reason of insanity."
Jnuary 1, 1996. Source: 8 Kan. J.L. & Pub. Pol'y 253 (1998-1999) Insanity Denied: Abolition of the Insanity Defense in Kansas; Rosen, Marc
The insanity defense is used by criminal defendants. The most common variation is cognitive insanity. Under the test for cognitive insanity, a defendant must have been so impaired by a mental disease or defect at the time of the act that he or she did not know the nature or quality of the act, or, if the defendant did know the nature or quality of the act, he or she did not know that the act was wrong. The vast majority of states allow criminal defendants to invoke the cognitive insanity defense. In Bundy's case, the defense didn't do much. He took the death penalty.
The Durham rule, established in 1954, states that a defendant is not criminally responsible if the unlawful act was a product of mental disease or defect. This rule expanded the legal definition of insanity in criminal cases beyond the M'Naghten rule.
the Federal Insanity Defense Reform Act
Some successful criminal defenses are used by the defense attorney to the accused and some defenses include: insanity, temporary insanity, and the non-guilty plea.