The criminal defense of insanity is among the many defenses a person charged with a crime in Missouri can mount during trial. A criminal defendant may plead not guilty by reason of insanity. This particular defense applies where a criminal defendant is determined to be legally insane at the time when he or she committed the crime. When a person facing criminal charges pleads not guilty by reason of insanity, he or she is admitting that they committed the crime but seeks not to be held responsible for the crime because they lacked the mental capacity to form criminal intent or to understand the wrongness of the act.
The criminal defense of insanity is well articulated in Missouri laws under section 553.030 (01). As per the provision, a defendant cannot be convicted for a crime they committed at a time they had a mental illness or defect that led to the lack of the mental capacity to appreciate the nature, quality, and wrongfulness of a criminal act. Persons who are determined to have been legally insane at the time of such conduct are neither legally or morally guilty.
The insanity defense is grounded on the principle that a criminal defendant can only be held legally responsible for committing a crime if he or she understood that the act in question was morally and/or legally wrong. Where a defendant lacked the mental capacity to understand the wrongfulness of their actions, they may plead not guilty by reason of insanity.
The state of Missouri tests for legal insanity using the M’Naughten rule, which is a test that evaluates whether or not the defendant understood the wrongness of their action and whether they were able to distinguish right from wrong at the time the crime, was committed. This rule is based on the belief that the accused may have had a mental disease or defect hence he or she could have been incapable of understanding their own actions.
According to the M’Naughten rule, the insanity defense can only be admissible in court if; the defendant did not understand the true nature of his or her conduct at the time the crime was committed, and the defendant was not capable of distinguishing right from wrong due to mental illness or defect.
A criminal defendant is presumed to be sane until proven otherwise beyond a reasonable doubt. The burden of proof of insanity lies with the defendant. If the insanity defense is to be used, it’s upon the defendant and their defense attorney to prove mental instability. A defendant can present evidence demonstrating mental instability using mental health documents or hospital records showing a history of mental illness and expert witnesses such as psychiatrists stating that the defendant was insane at the time of the crime. The standard of proving mental illness or defects is more strict than merely showing that the defendant could not distinguish between right and wrong.
Criminal defendants who are insane in Missouri do not get a free ride out of jail. Since they cannot be expected to distinguish right from wrong, they are often sentenced to a number of years of mandatory treatment in a mental health institution. A person adjudged insane may not be released from a mental health institution until they can convince a judge that they are no longer legally insane.
A person facing criminal charges in Missouri and he or she is considering the insanity defense should first seek the advice of an attorney. An experienced criminal defense attorney can evaluate a case and determine if pursuing the insanity defense can be advantageous for the specific situation.