Deconstructing the Insanity Defense

By: Jessica "Lulu" Lipman
​Jessica “Lulu” Lipman is a junior at the University of Pennsylvania studying English.

On March 30, 1981, John Hinkley JR. attempted to assassinate President Ronald Reagan. Although he failed in his attempt, Hinkley wounded four people, including the President. Hinckley was infatuated with the movie Taxi Driver, which centers around an assassination of a presidential hopeful. During his trial, Hinkley's defense argued that he was not culpable for his actions because he had schizophrenia and was in the midst of a major depressive episode. Ultimately, the jury in Washington D.C. determined that Hinckley was not guilty by reason of insanity, a decision that sparked debate amongst the American people [1].

The insanity defense is one of the most controversial criminal defenses in the U.S. court of law, and it is recognized as a legitimate defense in 46 states. This defense is contentious because a defendant can be found not guilty of some of the most heinous crimes, including murder, by reason of mental illness. This is an affirmative defense, meaning that the individual admits that they did commit the crime but that the person is not criminally liable because of a psychiatric disorder [2]. Despite what is depicted on television, the insanity defense is not widely used and is introduced in less than 1% of felony cases, and even fewer of these cases lead to an acquittal. One reason for this is because it is quite challenging to show that a person is legally insane, and there is not one standard method for proving insanity across different states. The accused person's council is responsible for showing that the individual did not have jurisdiction over their actions, such as if the person was sleepwalking, and would also have to show that the accused was incapable of forming criminal intent. Additionally, the person must undergo a thorough psychiatric evaluation [3]. 

​There are a few cases that have helped build the foundation for modern uses of the insanity defense. First, in 1843, Daniel M'Naghaten murdered the prime minister of England's secretary, mistaking him for the prime minister Sir Robert Peel. During the trial, M'Naghaten asserted that God ordered him to kill Peel. The British court found him innocent because of a "labouring under such a defect of reason, from disease  of the mind, as not to know the nature and quality of the act he was doing; or, if he did know it, that he did not know he was doing what was wrong." [4] Thus, the M'Naghaten rule contends that an individual is not criminally responsible for their actions if they did not know what they were doing or could not differentiate from right and wrong (and later became known as the "right-wrong test"). Its pitfall, however, is that the rule focuses on the ability to distinguish what is morally acceptable and what is not; it does not say anything about if a person can control their actions [5]. 

Over time, the M'Naghaten rule fell out of favor. Critics of the rule argued that it was outdated and did not take into consideration the new and emerging science regarding psychiatric disorders. Therefore, in 1954, in the case of Durham v. United States, a judge ruled that a person could be found not responsible for their crimes if the actions were as a result of mental illness. The burden of proof was to show a causal relationship between the individual's psychiatric disorder and the unlawful act that occurred. Eighteen years later, however, the Durham rule was rejected, because it was so difficult to implement [6]. Additionally, after Hinkley's acquittal, another verdict was adopted by 20 states, the Guilty but Mentally Ill (GBMI) defense, which is a verdict that states that a person is guilty and mentally ill, but that the mental illness was not the cause of the crime. This allows the accused person to get psychiatric treatment while in prison. This defense is also heavily debated, because it has not lessened the number of people who are found not guilty based on insanity and has only further stigmatized prisoners struggling with mental illness, by singling them out in prison settings. Further, studies have shown that most convicted persons found GBMI do not get adequate treatment [7]. In Pennsylvania and Georgia, for example, more than 80% of GBMI judgements are the outcomes of plea deals, as opposed to jury trials. Additionally, as of 2021, 12 states have implemented the GBMI verdict as a replacement to the insanity defense, and some states, like Nevada, have completely revoked the insanity defense in favor of GBMI [8]. 

Despite the controversy, the insanity defense is still used today. On April 13th, 2021, Manuel Gomez, a 47-year-old Nebraskan man, appeared in court to file a motion to use the insanity defense. Gomez is accused of murdering two people and seriously injuring a third in 2019. Later that year, he was found incompetent and unable to stand trial and was place in a mental health treatment center. The outcome of the trial is still unknown [9]. Additionally, in March of 2021, Brittany Gosney, a 26-year-old woman, and her boyfriend James Hamilton also requested to file a plea of insanity after being charged with killing her six-year-old son and attempting to abandon her other two children. She is set to face trial shortly [9].

Based on the pattern of overturned rules, it is unclear whether the insanity defense will continue to be used. Although it is rarely successful in acquitting people, as evidenced above, accused persons still will attempt to file a plea of insanity, despite the odds being against them.

The opinions and views expressed in this publication are the opinions of the designated authors and do not reflect the opinions or views of the Penn Undergraduate Law Journal, our staff, or our clients.
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[1] Jacewicz, Natalie, "After Hinckley, States Tightened Use Of The Insanity Plea" (28 July 2016). NPR. https://www.npr.org/sections/health-shots/2016/07/28/486607183/after-hinckley-states-tightened-use-of-the-insanity-plea
[2] Yaffe, Gideon. "Neurologic disorder and criminal responsibility." Handbook of clinical neurology vol. 118 (2013): 345-56. doi:10.1016/B978-0-444-53501-6.00029-9
[3] University of Minnesota Libraries Publishing, "Criminal Law" (2012) https://open.lib.umn.edu/criminallaw/chapter/6-1-the-insanity-defense/
[4] Nevid, Jeffrey S.; Rathus, Spencer A.; Greene, Beverly, Ph.D.. Abnormal Psychology in a Changing World (2-downloads) (p. 577). Pearson Education. Kindle Edition.
[5] Nevid, Jeffrey S.; Rathus, Spencer A.; Greene, Beverly, Ph.D.. Abnormal Psychology in a Changing World (2-downloads) (p. 577). Pearson Education. Kindle Edition.
[6] "Durham Rule" (N.D). Law Library – American Law and Legal Information. https://law.jrank.org/pages/6321/Durham-Rule.html
[7] Nevid, Jeffrey S.; Rathus, Spencer A.; Greene, Beverly, Ph.D.. Abnormal Psychology in a Changing World (2-downloads) (p. 577). Pearson Education. Kindle Edition.
[8] Gaskell, Steven, “Guilt But Mentally Ill (GBMI)” (2021). Psychological Assessments Inc. https://psycholegalassessments.com/areas-of-expertise/guilty-but-mentally-ill-gbmi/
[9] Bebensee, Ashley, "Holdrege man to use insanity defense in alleged killing of two men" (13 April 2021). Kearney Hub. https://kearneyhub.com/news/local/holdrege-man-to-use-insanity-defense-in-alleged-killing-of-two-men/article_8d5a63a4-9c9a-11eb-8fbe-5ff71f2a1cd7.html
[10] Eglito, Daniel, "Mom Accused Of Fatally Dragging 6-Year-Old Son As He Clung To Car Files For Insanity Plea" (22 March 2021). Oxygen. https://www.oxygen.com/crime-news/brittany-goseny-files-for-insanity-plea-in-son-james-killing