By now, you've probably heard about someone “pleading insanity” in a criminal defense case, but have you ever wondered what that actually means? With most states in the country having at least one version of an insanity defense, it often becomes even more confusing to figure out how it all works. To help you get a better understanding of exactly what an insanity defense is and what it means in a trial, we're breaking it down for you. 

Variations of the Insanity Defense

There are two variations of the insanity defense, which include cognitive insanity and volitional insanity. In the case of a cognitive insanity defense, a defendant in a trial would admit to committing the crime in question. However, this defense will raise the question of whether or not the defendant was mentally capable of knowing the act he or she committed was a criminal act. Alternatively, it may be said that the defendant knew what he or she was doing, but was incapable of telling right from wrong at the time of the incident.

When heading to a trial, the prosecution will seek to prove beyond a reasonable doubt that the defendant in the case had the willful intent to commit the crime in question. When pleading insanity, you're saying you couldn't have had the intent to commit the crime, which makes it more difficult for the prosecution to prove their case.

Alternatively, you could use the volitional insanity defense. This particular insanity defense is also known as the “irresistible impulse defense.” In this case, the defendant would admit to committing the crime and will acknowledge that he or she knew the acts committed were in fact criminal. However, this defense implies that the defendant was unable to stop from committing the crime and unable to control behavior at the time of the incident due to a mental illness. The defendant essentially states that he or she did not commit said crime voluntarily. In any case, the prosecution will seek to prove you had the willful intent to commit a crime and that you also did so voluntarily. Not being able to prove these things makes their case more difficult.

About the Insanity Defense

The insanity defense has actually been around since the late 19th century. In that time, there have been changes to what it means to plead cognitive insanity and the volitional insanity defense has nearly been eradicated.

Cognitive insanity standards first came about in England and were known as the M'Naghten Rule. As mentioned above, this particular rule required the defendant in a case to prove he or she did not know the nature and quality of the act that was committed. The other option was for the defendant to prove that the nature of the act was known, but he or she did not realize committing said act was wrong.

Since these standards first came about, a more lenient version, known as the Durham Rule, came out in the late 19th century and was followed by many states. It didn't last long. This updated rule made it much easier for defendants in a trial to plead and prove insanity. In 1962, the American Law Institute created a new standard for their Model Penal Code to build off of these rules.

These days, states around the country have created tougher standards for the insanity defense or have dropped the defense altogether. For many, the defense has to prove the defendant is insane, rather than the prosecution having to prove the defendant is sane.

There has also been a lot of criticism surrounding the insanity defense. Many believe pleading insanity gives defendants in a trial the opportunity to fake insanity and essentially not have to take responsibility for crimes that they committed. However, it's worth mentioning that only an estimated 1% of defendants across the nation have actually used the insanity defense in a trial. When this particular plea is used in a case, in only has about a 20% success rate.

Critics of the insanity defense are often concerned that defendants in these trials are then free to roam the streets once all is said and done. This simply isn't the case. In most instances, these defendants are sent to a mental health facility, where they will reside until they are no longer deemed to be a danger to themselves and society. Although they won't be sentenced to time in jail, the time they spend in mental facilities often ends up being a very long period of time.