The insanity defense, as well as the details that go into its consideration, both psychologically and legally, is fascinating. This exploratory analysis will delve into what exactly the insanity defense is, what factors influence the success, or lack thereof, of the defense, and how the rare instances of this legal ruling were handled by the court system. This paper will also examine both sides of the debate of whether the defense is valid or not, as well as addressing how each offender was sentenced after their rulings. The topic is important for individuals to understand because there is a lot of misunderstanding as to what exactly the defense means and why it so rarely works. Although it may be a bit complex in terms of technicalities, once one understands the factors that must be considered, it is an easy topic to understand. The best way to understand the differences between cases in which the defense worked, and in ones it did not, is to compare multiple popular cases, particularly those of famous criminals such as Jeffrey Dahmer, and, more recently, the case of the “Slender Man Stabbing” committed in 2014 in Wisconsin by two young girls.

First and foremost, it is important to know what the insanity defense is by definition. The article The Insanity Defense: A Closer Look, written by John P. Martin for the Washington Post, states that the insanity defense refers to a plea that defendants are innocent due to the lack of mental ability to recognize a wrongdoing and why it is classified as such (Martin). Despite how often the use of this defense is attempted, it is rarely successful because the process of making the decision to accept the case takes careful consideration of the mental status of the perpetrator at the time of the crime, as well as examining their personal history for psychological abnormalities, prior offenses, and possible triggers for their behavior. Just one small detail can change an entire court ruling either in favor, or against the perpetrator. On the legal side of things, it also takes substantial consideration of the degree to which the perpetrator is guilty. 

The article Psychoanalysis of the Insanity Plea written by Albert A. Ehrenzweig from the Yale Law Journal Company LLC, offers legal insight to the insanity defense. The article claims that there are a lot of factors that cannot be proven in favor of the defense and that regardless of the mental status of the defendant, and the findings of the appointed psychiatrist, their crimes should be punished according to the severity of their crime. This brings into light that there is a very intricate back and forth going on between judge and psychiatrist in the courtroom. Under current tests, the accused is deemed to be sane at the time of the crime if they knew the nature and quality of their act, and also knew that their act was wrong (Ehrenzweig). However, this “modern” test, is over a century old, and out of date in current times (Ehrenzweig). The fact that the test is out of date leads to much disagreement between psychiatrist and jury because when told the test is wrong, psychiatrists respond with “what does the wrongness have to do with their expert knowledge of mental disease?” (Ehrenzweig). When looking at the big picture in insanity defense cases, the court must please themselves, the psychiatrists, and the whole public in general. If any of the parties are not happy with the possible verdict, the case becomes messy.

The defense is also highly controversial, gaining many different opinions on the topic, as many argue that defendants use this method as a way of faking insanity to obtain a lesser sentence (Martin). There also exists a subcategory to the insanity defense, sometimes referred to as the “irresistible impulse” defense, which means that the defendant realizes that their behavior was criminal in nature, but were unable to control themselves at the time of the crime (Martin). Such behavior is described by Dr. Isaac Ray as people claiming to be “irresistibly impelled to the commission of criminal acts while fully conscious of their nature and consequences; and the force of these facts must be overcome by something more than angry declamation against visionary theories and ill-judged humanity” (Keedy 956). The publication by Dr. Ray was later followed by Dr. Forbes Winslow’s statement that 

“A person may be perfectly competent to draw a correct distinction between right and wrong, and yet labour under a form of insanity which ought unquestionably to protect him from legal or moral responsibility. I allude to cases of insanity where the patient is driven, by an irresistible impulse, to destroy, after struggling, for some time, against the morbid desire, being, at the same time, perfectly conscious that he is impelled to do what is wrong both in the sight of God and man” (Keedy 957).

An example of the “irresistible impulse” plea that was described by Dr. Forbes Winslow was the case of Lorena Bobbitt, who argued that she was temporarily insane when she removed her husband’s genitals with a kitchen knife while he was asleep after he raped her, and threatened that if she left him, he would find her and rape her again, and that there was nothing she could do to stop it (Martin). Once she realized the severity of her actions she called the police and they retrieved the severed appendage from the field in which she threw it, and it was promptly reattached to Mr. Bobbitt’s body (Cambridge). The jury agreed to her irresistible impulse defense due to the circumstances and she was released after a few months of psychiatric evaluation (Martin). Claims of innocence due to insanity or irresistible impulse are used in a variety of cases, however, the most well-known are cases of mass murder or cases that are extremely weird in general. 

The first case that will be examined is that of Jeffrey Dahmer, a notorious serial killer, who attempted, unsuccessfully, to use the insanity defense. The plea was rejected do to the fact that Dahmer knew his actions were wrong and abnormal, yet continued with them anyways, despite the presence of early childhood neglect, a pre-existing fascination with death, and that he was later highly influenced by adult psychopathic behavior (Higgs 1). Early in his life, Dahmer experienced several instances of what is described as childhood trauma (Higgs 9). His adolescent struggles began when he underwent surgery for a hernia at age 4, then continued when he constantly witnessed his mother’s odd behavior as a result to anti-anxiety medication (Higgs 9). His parents left him to fend for himself most of the time while they were bust fighting between themselves (Higgs 9). It is also rumored that Dahmer was sexually assaulted by a peer in his neighborhood, which also influenced the nature of his adult actions (Higgs 10). Each of these experiences led to Dahmer’s exhibition of anti-social behavior, which means that he showed no care of being socially “normal” or following societal rules regarding morality and was also more prone to exhibiting violent behavior. Also, as a result of his long stints of time alone, he developed a fear of abandonment. Each of these situations played into the details reported later in his crimes. 

His first murder took place in 1978 at the age of 18 (Crime Museum). At this time, Dahmer’s parents were undergoing a divorce, leaving Dahmer in his home alone allowing him to take advantage of the opportunity to act on his murderous impulses that he had been keeping under wraps in his mind (Crime Museum). He picked up a hitchhiker by the name of Steven Hicks and invited him to his home to drink a beer and when Hicks attempted to leave, Dahmer struck him over the head with a dumbbell then dissected, dissolved, pulverized and scattered Hicks’ remains in his backyard (Crime Museum). He later admitted to the murder and gave his reasoning as that he simply did not want Hicks to leave, thus playing into Dahmer’s fear of abandonment (Crime Museum). Dahmer then went for an extended period of time without killing another victim and in that time, attempted to attend university, but dropped out due to his alcoholic tendencies, which led to Dahmer’s father forcing him to enlist in the army (Crime Museum). During his time in the army, he served as a medic in Germany, however, he was discharged because of his continual alcohol addiction (Crime Museum). Between 1982 and 1986, Dahmer was arrested on two separate occasions because he drugged and raped men as they were unconscious, yet he was only charged for indecent exposure, not for rape (Crime Museum).

Dahmer went on to kill seven people from 1988 to 1990 where he followed the same system in which he lured, drugged, raped, strangled his victims and partook in necrophilia after their death (Crime Museums). He kept gruesome photographs of the dismemberment process, then preserved the victim’s skulls and genitals to display to himself (Crime Museums). In his 1991 murders, Dahmer began experimenting with at-home lobotomies in which he would inject victim’s brains with acid and boiling water to make them submissive partners. One of his lobotomy victims was able to escape and asked for help, but Dahmer convinced the police that he was just his drunk boyfriend and the police never ran Dahmer’s background check. The fact that Dahmer was able to calmly and effectively convince the police that it was all a misunderstanding shows his lack of care for authority and although very twisted, his overall mental sanity.

Dahmer ultimately confessed and was indicted on 15 murder charges, but he pled not guilty by reason of insanity because he claimed that he could not control his impulses. The insanity plea was unsuccessful and he was charged with 15 counts of murder, which later increased to 16 counts upon his admission to the murder of Steven Hicks. (Crime Museum). Looking at the big picture of this case, although Dahmer exhibited evidence of being mentally ill, he showed no evidence of being criminally insane. He knew his actions were wrong, yet he planned them down to every last detail, made sure to hide any evidence, and stuck to a very structured routine for his killings. Ultimately, Dahmer was too smart with the details of his crimes to be considered insane despite the fact that he was mentally ill. However, mental illness does not a constitute mental insanity.

In more recent news, the case of the “Slender Man Stabbing” made headlines as a case that used the insanity defense successfully (CBS News). Slender Man is an extremely popular fictional character on internet platforms that got its start on a website called Creepypasta that specializes in original horror stories written by users of the website. In this case, two girls, Anissa Weier and Morgan Geyser (ages 12) lured their fellow classmate, Payton Leutner (also age 12), into the woods in 2014 where Geyser stabbed Leutner 19 times while Weier urged her on; however, Leutner survived the attack (CBS News). The girls were under the shared delusion that if they did not murder Leutner, then Slender Man would murder their families (CBS News). This shared delusion, where the girls also believed that Slender Man could read their minds and teleport to kill their families if he was spoken about, was present during the time of the attempted murder (CBS News). This case is a clear-cut example of a successful use of the insanity defense, as it is very clear that at the time of the crime, the perpetrators were mentally ill.

Despite cases such as the “Slender Man Stabbing”, many people oppose the insanity defense. It is argued in Valerie P. Hans’ article An Analysis of Public Attitudes Towards the Insanity Defense that people do not support the defense, as they want insane lawbreakers punished for their actions (Hans). It is also believed by those in opposition that the allowance of the insanity defense fails to protect the public (Hans). However, these beliefs stem from the misconception that the insanity defense acts as an easy way out for criminals. These individuals also do not realize that by taking away one’s right to plea insanity for their defense, they are also taking away their right to Due Process rights.

Stephen Morse, who argues in favor of the insanity defense, states in his article Abolition of the Insanity Defense Violates Due Process that “the affirmative defense of legal insanity has such a strong historical, moral, and practical pedigree and is so ubiquitous that providing some form of an insanity defense is a matter of fundamental fairness in a just society. It gives doctrinal expression to fundamental moral and legal principles that have been recognized by the common law for centuries and that the Supreme Court has repeatedly acknowledged” (Morse 488). 

He also states that jurisdictions have ample leeway in deciding which testing method best meets their legal or moral policies, and that ultimately, some form of the insanity defense is required by the Due Process Clause (Morse 498). Morse argues that it is unfair to place blame and punishment on an offender who is truly not responsible for their actions (Morse 498). If one cannot control their actions, then it is unconstitutional to take away the defense that could help them receive a justified ruling. It is also stated that even though these offenders are using this defense, it does not excuse them from their crimes, however, it allows that court to punish them in a fair way that takes their mental sanity into consideration. 

With all of this considered, the best way to understand the difference between a successful and unsuccessful insanity plea is to compare multiple cases and see which factors are present in each. Most commonly, in a successful plea, the perpetrator was clearly mentally ill or declared insane at the time of the crime, for example, the Slender Man stabbing in 2014, or the case of Lorena Bobbitt. It is more difficult to see in cases like that of Jeffrey Dahmer, where he was clearly psychologically abnormal, yet not classified as criminally insane. This shows just how fine of a line there is between mentally ill and insane. For that reason alone, it shows just how important it is for people to understand what the insanity defense is, and what factors and technicalities must be considered in its ruling. Although many believe that the insanity defense is an easy out for criminals, it is in fact a necessary possibility for those that truly are criminally insane and pose a risk to society and themselves. The defense also lets those that are successful get quality treatment for their disorders. Each of these small details and subjectivity between cases is what makes this topic so interesting to explore. 
