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Last Updated on: 3rd October 2023, 06:52 pm

The insanity defense is one of the most commonly known defenses in the criminal justice system. It is also a fairly commonly used defense. The insanity defense has a lot of variations to it as well, which depend on which state the defense is being implemented in. The insanity defense tends to make media headlines so frequently because of the intensity of the crimes. For example, in 2012 during a movie theatre showing of a batman film, James Holmes walked into the theater and starting shooting.[i] James Holmes killed 12 people that night and injured another 70 innocent individuals. The defense counsel for James Holmes presented an insanity defense to the court, but in the end it was rejected.[ii]  Even though the defense was rejected, the general public will always remember James Holmes as the crazy man who shot up a movie theatre during the batman movie. This tends to be how insanity defense cases are remembered – even when

What is the Insanity Defense?

What exactly is the insanity defense? Even though you may think that your mother in law is crazy, there are specific factors that must be met in order to be considered for the insanity defense. The factors of this defense are based heavily on statutes and vary depending on the state where the crime took place.[iii] The insanity defense is generally based on the principle that punishment is only justified where the accused was capable of controlling their behavior and understood that his actions were wrong. If the accused lacks those abilities, then the defense of insanity would play a vital role. The insanity defense provides a shield from punishment for those who are unable to understand their actions.[iv]

The general insanity defense is not just one defense that covers all types of insanity – there are many different areas within the defense that may be used, but again this will depend on the jurisdiction where the trial is taking place. The M’Naghten test for insanity is one of the most common types of insanity defenses.[v] The M’Naghten test has been utilized by the court system since1843 and was developed based on an English case.[vi] An offender is deemed insane under the M’Naghten test if the mental illness that afflicts them prevents the offender from knowing the difference between right and wrong.[vii]  An example of insanity under this test would be the following. A man murdered his wife and daughter, and then waited calmly for the police to arrive.[viii] Three mental health experts testified that he was too psychologically ill to understand that his criminal acts were wrong.[ix] He was found not guilty by reason of insanity and sentenced to ten years in a mental health facility.[x]

Since the creation of the M’Naghten test, some jurisdictions have created a blending of that rule with more elements. Under what is known as the Brawner Test, an accused is insane if, by mental insanity defense testdefect, they lack the substantial capacity to appreciate the criminality of their actions or the ability to conform their behavior to legal requirements.[xi]

Other states take it a step further and add in what is known as the irresistible impulse test.[xii] Under this test, the accused will be deemed insane if a mental disorder prevents the accused from resisting the commission of an illegal act that they know is wrong. This could be a harder defense to prove since the accused still had the ability to know their actions were wrong, but could not control themselves.

Many people believe that if an accused person is found guilty by reason of insanity, that just because they do not need to go to jail they will just be let off. This is simply not true. Those who are found guilty by reason of insanity are rarely set free after the trial. Rather, the accused will then be confined to a mental health institution, which in some cases may mean they will be confined for longer than they would have been if they had just gone to jail.[xiii] Typically, the accused will remain in the mental health facility until they can prove to the judge that they are no longer legally insane.[xiv] And for some, this day may never come.  Find out more information about the insanity defense but contacting an experienced criminal defense lawyer in Phoenix.

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Some of the Most Notorious Insanity Defense Cases

Just like the James Holmes case, the public tends to remember certain type of cases over others: brutal murders and insane people. There are dozens of articles about not only the insanity defense, but the real fasciation is with the individuals who try to assert the insanity defense.

The first use of the insanity plea in the United States was from defendant Daniel Sickles in the late 1850s.[xv] Daniel Sickles was known for being a New York Politician and Civil War General.[xvi] Daniel Sickles was also known for his infidelity and indiscretions with women. The greatest scandal that Daniel Sickles was apart of was the one that led him down the path to the insanity plea.[xvii] He witnesses his wife having an affair with another man and shot and killed this man.[xviii] The jury for Daniel Sickles’ trial was comprised of all men, who accepted his plea of insanity and acquitted his murder charges.[xix]

In 1941, two brothers robbed a truck in New York.[xx] In the process of the robbery, the two brothers killed an office manager and a police officer.[xxi] The two brothers attempted to assert an insanity defense at the trial through extreme behavior in the courtroom.[xxii] Basically, the two brothers would bang their heads against the table until they bled, bark like dogs, cry, or just sit and drool.[xxiii] The court did not accept their insanity plea and charged the brothers for the murders the committed.[xxiv] This case still has the record for the fastest verdict return; it only took the jury one minute to deliberate for this case.[xxv] Each brother was executed by electric chair by 1942.[xxvi]

famous insanity defense casesIn Arizona 1981, Steven Steinberg was charged with killing his wife with a kitchen knife, which he used to stab her 26 times.[xxvii] This case because so highly publicized because it was a case of homicidal somnambulism: sleep walking murder.[xxviii] The legal argument presented in this case stated that the defendant was not in his normal state of mind when he committed the act because sleep walking is a parasomnia.[xxix] Basically, whatever the person does while sleep walking cannot be blamed on the person.[xxx] The jury believed this story and found Steinberg not guilty on the grounds that he was temporarily insane when he committed the crime.[xxxi]

Also in 1981, John Hinckley Jr. who was responsible for the attempted assassination of President Ronald Reagan used an insanity defense for the crime.[xxxii] Apparently John Hinckley Jr. was so obsessed with Jodie Foster after seeing her in the movie Taxi Driver that he began to stalk her to the point of moving across the country to be closer to her.[xxxiii] John Hinckley Jr. would send Jodie Foster love letters and poetry, but she would never respond to him.[xxxiv] In order to try to get her attention, John Hinckley Jr. thought that an attempted assassination of President Ronald Reagan would get her attention.[xxxv] John Hinckley Jr. shot President Ronald Reagan six times as he left the Hilton Hotel but only one bullet managed to hit him.[xxxvi] The bullet hit the president in the chest, but he survived. John Hinckley Jr. pled insanity for the charge and was successful on all 13 charges of assault, murder, and weapon counts.[xxxvii]

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In 1993, Lorena Bobbit had had enough of the physical abuse of her husband John Bobbit.[xxxviii] John Bobbit had a history of mentally and sexually abusing Lorena throughout their marriage.[xxxix] One night after John Bobbit had raped Lorena, Lorena was standing in her kitchen and saw a carving knife on the counter.[xl] Lorena was overwhelmed with memories of abuse from her husband, so she picked up the knife, walked into the bedroom where John was asleep and cut off almost half of his penis with the knife.[xli] Lorena then left the apartment, with severed penis in hand, and drove to a field and threw the penis away.[xlii] Shortly after Lorena called the police to inform them of what happened. Luckily for John, the search team found his penis and was able to reattach it.[xliii] At trial, Lorena testified about the details of their abusive marriage, and claimed that she was suffering from clinical depression from causing the wound to her husband.[xliv] The jury returned a verdict of not guilty on all charges based on the grounds of temporary insanity.[xlv] Lorena was ordered to spend 45 days going through a psychiatric evaluation but was released once it was completed. Lorena was even interviewed on Opera to discuss how she survived an abusive marriage.

Conclusion to the Use of the Insanity Defense and High Profile Cases

The insanity defense is a well known criminal defense, and often times people remember insanity defense cases better than any other cases. This is an interesting fact considering that the insanity defense is used less than 1% in all court cases in the United States.[xlvi] When the insanity defense is used, it is only successful about 26% of the time.[xlvii] And of those successful cases, 90% of the defendants had been previously diagnosed with a mental illness.[xlviii] So even though these cases are not as common as the media would lead us to believe, the citizens of the United States seem to be so fascinated with the criminally insane nonetheless.

[i] See Powerful Photos Released from Aurora Theatre Shooting CBS News (Accessed July 27, 2016)

[ii] See ‘He is Sane’: James Holmes Trial Showed That The Insanity Plea is a Mess Fusion (Published July 17, 2015)

[iii] See Defenses to Criminal Charges NOLO Legal Encyclopedia (Accessed July 19, 2016)

[iv] Id.

[v] See Pleading Insanity in a Criminal Case NOLO Legal Encyclopedia (Accessed July 19, 2016)

[vi] Id.

[vii] Id.

[viii] See The M’Naghten Rule Find Law (Accesed July 15, 2016)

[ix] Id.

[x] Id.

[xi] Id.

[xii] Id.

[xiii] Id.

[xiv] Id.

[xv] See Top 10 Most Notorious Insanity Defense Cases List Verse (Published April 11, 2016)

[xvi] Id.

[xvii] Id.

[xviii] Id.

[xix] Id.

[xx] Id.

[xxi] Id.

[xxii] Id.

[xxiii] Id.

[xxiv] Id.

[xxv] Id.

[xxvi] See Top 10 Most Notorious Insanity Defense Cases List Verse (Published April 11, 2016)

[xxvii] Id.

[xxviii] Id.

[xxix] Id.

[xxx] Id.

[xxxi] Id.

[xxxii] Id.

[xxxiii] Id.

[xxxiv] Id.

[xxxv] Id.

[xxxvi] Id.

[xxxvii] Id.

[xxxviii] See Top 10 Most Notorious Insanity Defense Cases List Verse (Published April 11, 2016)

[xxxix] Id.

[xl] Id.

[xli] Id.

[xlii] Id.

[xliii] Id.

[xliv] Id.

[xlv] Id.

[xlvi] See Insanity Defense Wikipedia The Free Encyclopedia (Accessed July 20, 2016)

[xlvii] Id.

[xlviii] Id.