How Often is the Insanity Defense Used?

The insanity defense has been used in some high profile cases. However, it is used sparingly in Arizona and elsewhere in the United States.

According to a PBS report, the insanity defense is used in just 1 percent of felony cases and it is successful in less than a quarter of the cases it is used in. The figures are derived from an eight-state study commissioned by the National Institute of Mental Health in 1991.

Although high-profile cases like those of serial killers Jeffrey Dahmer and John Wayne Gacy highlighted insanity defenses, in reality, they are seldom used. You should hire a lawyer who is specialized in these difficult cases involving mental health.

The insanity defense was first developed in 16th Century England. It was codified in the M’Naghten Rule in the 19th Century.

Use of the insanity defense in Arizona
When the insanity defense is used in Arizona

In that case, a court ruled a “disease of the mind” meant the defendant failed to understand what he did was wrong and was unable to distinguish the difference between right and wrong.

Most states use a variation of the rule. Arizona has a guilty except insane defense. The burden to prove insanity is on the defense.

Many states amended their insanity laws in 1982 when John Hinckley was acquitted of the attempted assassination of President Ronald Reagan on basis of insanity. Hinckley was found not guilty by reason of insanity and committed to St. Elizabeth’s Hospital in Washington. Hinckley was released in 2016. He must live within a 75-mile radius of Williamsburg, Virginia where his mother resides. He must maintain contact with his doctors twice a month while continuing ongoing group and individual therapy sessions, reported CNN.

In the aftermath of the Hinckley case, states started to require defense attorneys to show evidence that the defendant is insane, instead of the prosecutor. Four states – Kansas, Idaho, Montana, and Utah eliminated the insanity plea altogether.

Arizona has a strict interpretation of the insanity defense. The defendant is barred from presenting evidence of diminished mental capacity to negate the prosecution’s claims he acted with criminal intent.

In the case of Clark v. Arizona in 2006, the U.S. Supreme Court held in a 5-to-4 decision that Arizona was entitled to limit the use of evidence from experts about a defendant’s mental state to his insanity defense. A defendant is presumed to be sane until he proves otherwise. Justice Souter argued that allowing the accused to use insanity evidence to show that he could not form the necessary criminal intent would enable him to circumvent that presumption.

Arizona’s guilty except insane (GEI) defense is complicated and requires expert knowledge from a legal professional. Call Bernardo Garcia today if you or a family member has been arrested at (602) 340-1999.