The Insanity Defense in Criminal Trials

We often hear the phrase that someone is guilty by reason of insanity. It is referred to in crime movies, television shows, and books so much that we are led to believe this type of criminal defense is common. 

But surprisingly, this defense plea is only used in a fraction of cases. Defendants offer an insanity defense at trial in less than 1% of felony cases, and though we have successfully made this argument, it is difficult to prove. In general, this defense is successful about one-quarter of the time. 

Our lawyers explain pleading guilty by reason of insanity as a possible defense strategy.  

Myths and Truths About the Insanity Defense 

There are many myths around this defense, often suggesting that the alleged criminal is “getting away with it” or it’s on “a technicality.” Criminal justice research has shown: 

1. Few defendants “fake” insanity; most who plead insanity have a long, documented history of mental illness, treatment, and/or prior hospitalizations. 

2. If the defense goes with the insanity plea, the accused admits to the crime; in these cases, our defense experts and those for the prosecution also agree on whether the defendant was legally insane when the crime occurred.

3.  A proven insanity defense most likely means commitment to a mental institution or another healthcare facility, not the opportunity to walk away from the charge if found not guilty. 

4. At sentencing, if found not guilty by reason of insanity you or a loved one may spend more time in a treatment facility than what may have been faced if found guilty. However, the key difference is getting the mental health care needed. 

Legal Insanity Origin 

This rule originated in 1843 in England as the first legal test for criminal insanity.  

The defendant in the case, Daniel M’Naghten, shot and killed the secretary to England’s prime minister, believing that the secretary was the prime minister. During the trial, M’Naghten’s counsel declared a defense of insanity and brought forth evidence and expert testimony to support this plea. The jury’s verdict declared the defendant not guilty “by reason of insanity,” and M’Naghten spent the rest of his life in a mental institution.

England later altered the M’Naghten Rule to state that a criminal defendant is presumed sane and must demonstrate that he is not otherwise. 

A revised M’Naghten Rule to this day is used in Florida as the determination of insanity. 

Florida Definition of Insanity 

Florida Statute 775.027: 

(1) AFFIRMATIVE DEFENSE.—All persons are presumed to be sane. It is an affirmative defense to a criminal prosecution that, at the time of the commission of the acts constituting the offense, the defendant was insane. Insanity is established when: 

(a) The defendant had a mental infirmity, disease, or defect; and 

(b) Because of this condition, the defendant: 

1. Did not know what he or she was doing or its consequences; or 

2. Although the defendant knew what he or she was doing and its consequences, the defendant did not know that what he or she was doing was wrong. 

Mental infirmity, disease, or defect does not constitute a defense of insanity except as provided in this subsection. 

(2) BURDEN OF PROOF.—The defendant has the burden of proving the defense of insanity by clear and convincing evidence. 

History.—s. 1, ch. 2000-315. 

Preparing for Trial 

Defendants have to advise prosecutors prior to trial if they plan to rely on an insanity defense. Typically, both your defense attorneys and prosecutors will obtain our own expert psychiatrists. 

This competency evaluation is performed and then they form a professional opinion on whether the defendant is insane. If there is a disagreement between the two, a third evaluator will make an assessment.  

More often than not, these mental health experts are in agreement for the insanity defense to succeed. 

At Trial: Insanity Defense in Florida 

For an insanity defense to prevail, the defendant must demonstrate that they did not intend to commit the crime and be unaware that the result was a foreseeable consequence of their actions. We have the burden of convincing the judge or jury through either a preponderance of the evidence or by the standard of clear and convincing evidence the defendant was insane at the time they committed the crime. 

Defense psychiatrists are barred from testifying to an opinion that a defendant was legally insane at the time of the offense. They can only testify regarding a medical diagnosis concerning the mental illness. 

What to Expect at Sentencing 

If, or when, the defendant is declared legally insane, the person can be committed to a mental institution for treatment. It does not mean they are released back into society as if the crime had never occurred. Again, this defense is not a “Get Out of Jail Free” card.  

Defendants found not guilty by reason of insanity are almost always confined in mental health institutions or received other court-mandated treatment. Occasionally, they may remain confined longer than had they been found guilty and sentenced to prison.  

Using an Insanity Defense 

If you or a loved one has been charged with a crime and you believe that the insanity defense is appropriate, you will need the best criminal defense attorneys by your side. As we mentioned, proving the insanity defense has become increasingly more difficult. 

This defense requires experienced and knowledgeable attorneys such as those at Stechschulte Nell.  

Here, we offer free consultations with a legal specialist. Our top-rated defense team is happy to discuss your case in person, virtually, or over the phone. Call us at (813) 280-1244 we will handle your case with care and will do everything we can to achieve a favorable outcome at trial.  

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