Reforming the Insanity Defense: The Need for a Psychological Defect Plea

By Allyson L. Gay
2010, Vol. 2 No. 10 | pg. 1/1


It is not a coincidence that society refers to serial killers as psychos. Psycho is a word used in common language to refer to those with abnormal psychology, exactly what a serial killer portrays. Serial murder is a psychological crime in many aspects. It is a planned, thought out action. The crimes themselves are often committed in order for the killer to gain a sense of power, control and domination – all psychological desires and perceived needs – that are otherwise lacking in his/her life. Jack Levin (2008) could not have put it better in stating “sociopaths (or psychopaths) are never remorseful when they do the wrong thing. They can therefore kill with moral impunity.” This lack of empathy shows a psychological defect that should be considered during a criminal trial.

Although most serial killers suffer from at least one of a variety of personality disorders, including psychopathy and anti-social personality, most are not found to be insane under the law (Mueller, 2005). Serial killers intelligence, like other populations, ranges from borderline to above average levels (Mueller, 2005). However, serial killers are meticulous planners, but more importantly, they are masters at building facades. They want the world to see them as calculating, manipulative and creative. They must select, target, approach, control, and dispose of their victims, a complex process which takes a lot of thought and meticulous planning. Due to the thoroughly psychological nature of serial murder, it is important to study the psychological workings of serial killers to understand their crimes.

In today’s society, pleading insanity is the hardest defense to successfully achieve. Society believes that the insanity defense is used far more often than it actually is and people believe that the defense is used as a tactic to avoid punishment. People perceive serial killers as inhumane and question how they could ever commit the crimes that they do. However, few want to believe that they are legally insane and agree with allowing them to plead guilty by reason of insanity. It is clear that serial killers suffer from psychological disorders, which is why we as a society need to present a new defense, a psychological defect plea. With a defect plea, the serial killer would still serve time for his or her crimes but could not be put to death. He or she would be able to receive treatment or therapy and would be subjected to psychologists and criminologists’ studies.

Insanity Defense

The first formal definition of legal insanity was adopted with the trial of Daniel M’Naghten in 1843. The M’Naghten test states:

It must be clearly proved that, at the time of the committing of the act, the party accused was laboring 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 what he was doing was wrong. (As cited in Krauss & Lieberman, 2009)

This test is still used commonly throughout the United States. In 1954, the Durham test expanded the insanity standard to any behavior that might be the product of a mental disorder (Krauss & Lieberman, 2009). In 1962, the American Law Institute (ALI) proposed a legal standard that stated:

A person is not responsible for criminal conduct if at the time of such conduct as a result of mental disease or defect he lacks substantial capacity either to appreciate the criminality (or wrongfulness) of his conduct or to conform his conduct to the requirements of law. (As cited in Krauss & Lieberman, 2009)

The Durham test is no longer used, as it was phased out by the ALI standard. The most common insanity defense used in the United States today are some restrictive version of the tradition M’Naghten test or the ALI standard.

In 1994, Silver et al. found that .9 percent (less than one per one hundred felony indictments) resulted in the use of an insanity defense (Krauss & Lieberman, 2009). In 1996, Jonofsky found that in Baltimore City, less than one percent of indictments (.31 per 100) had an insanity plea. He also found that successful insanity pleas represented less than one percent (.013 acquittal per 100 indictments).

Psyche of Serial Killers

Personality disorders have not generally been viewed as sufficiently severe to meet the mental disorder or mental defect requirement of most insanity statutes (Krauss & Lieberman, 2009). Sexual sadism, psychopathy, and anti-social personality are the three main types of psychological diseases and personality disorders that serial killers suffer from. Sadistic serial murderers often rape, torture, and brutalize their victims before the murder even occurs. In his article, Simons states:

“The psychopath at first glance seems quite ‘well put together.’ He suffers neither delusions, hallucinations, not memory impairment; contact with reality appears solid; however, he is unable to conform behavior to social norms, defer gratification, control impulses, tolerate frustration, profit from corrective experiences, or identify with others and form meaningful relationships with them.” (Simons, 2001)

When reading this, it is easy to understand why psychopathy does not fit the M’Naghten test. However, a serial killer suffering from psychopathy cannot control his or her impulses, identify with others and feel empathy, and cannot conform his or her behavior to social norms. Thus, proving he or she cannot possibly be completely competent and responsible for their actions, no matter how heinous.

Sadistic killers are broken down into three main categories, and five subcategories, of which only one, the visionary sadist, can argue insanity as it is now. The visionary sadistic killer is the must uncommon of the sadistic lust killers, the sexual sadists. These sadistic killers suffer from hallucinations and/or delusions – hearing or seeing visions instructing he or she to kill. The visionary killer is considered psychotic or insane and typically, these are the serial killers who successful achieve an insanity defense.

The second two, mission-oriented and hedonistic, cannot currently argue an insanity defense. Mission-oriented sadistic killers work to eliminate what they believe is an undesirable group of people. They do not suffer from delusions or any apparent psychological shortcomings, and they understand that what they are doing is wrong and thus cannot argue insanity. The third type, the most common and most dangerous, is the hedonistic sadistic killer. Hedonistic sadistic killers are broken down into five subcategories: the lust-oriented type, thrill-oriented type, comfort-oriented, control-oriented, and predatory.

The lust-oriented killer can be either organized or disorganized. The disorganized asocial type usually has below average intelligence and is socially and sexually incompetent (Simons, 2001). The organized nonsocial type usually has above-average intelligence and is socially and sexually competent, and typically strategically targets strangers (Simons, 2001). The thrill-oriented killer is motivated by a need for excitement, which he or she finds in killing. He or she needs his or her “victim to be alive and aware of the degradation before being killed” (Simons, 2001). Thrill-oriented killing involves a drawn-out murder because the killer derives most of his pleasure from the process of the murder rather than the actual kill itself (Simons, 2001). Comfort-oriented killers murder to profit economically from the death, usually through inheritance of money, property, etc. (Simons, 2001). Women serial killers often fall into this category (Simons, 2001). Control-oriented killers find gratification in having power over their victims, “especially the thrill of deciding whether a person will live or die, [as well as] how and when” (Simons, 2001). Predatory killers are attracted to the hunt and kill, and view killing as a sport or recreational activity (Simons, 2001). Currently, all of these five subcategories lack sufficient psychosis symptoms to allow them an insanity defense. However, the question then becomes are they really psychologically and mentally competent.

Many serial murderers fit the profile for having an anti-social personality disorder (Simons, 2001). Holmes and DeBurger (1985) contend:

“Affected individuals are often quite intelligent and charming and are free from psychosis and neurosis. They are good at manipulating people for their own ends and prefer to have superficial relationships with others rather than close and intimate friendships. They have almost no capacity to put themselves in the place of their victims and, therefore, have no sympathy for them.” (As cited by Simons, 2001)

Unlike serial killers with psychopathy, those with anti-social personality disorder should not be allowed to plead guilty by reason of insanity. They lack empathy but otherwise understand what they are doing. Unlike serial killers with pscyhopathy they manipulate the system to benefit their own means to an end. Allowing this disorder to fall into the insanity defense would feed into their disorder in that it would allow for the manipulation of the system to benefit their own ends, which would increase the societal biases that insanity pleas are generally a tactic not a defense.

Societal Biases

Societal biases are a major concern in the court system because they can change a verdict depending on the biases of jurors. Cesar Barone was a sociopath who murdered at least five women. Jack Levin testified at his trial stressing to the jury that serial murderers spending life in prison are more cooperative and we can learn more from them than serial murderers on death row. Barone was sentenced to death because the jurors believed he would never be executed due to the fact that then state of Oregon had not executed anyone since 1997. Upon appeal, Barone’s legal team quoted a juror’s exchange with the defense team during the discovery phase. This quote is the perfect example of societal biases affecting the verdict.

“I believe, when you get a personality type such as Ted Bundy’s, there is virtually no chance for rehabilitation. I believe, yes, they should be executed. I don’t believe the American public should have to support them. They serve no constructive good for society. ... There [are] a lot of people who have that [had a terrible childhood, had been abused, and neglected, and mistreated] that don’t go out and do these things” (Levin, 2008).

She is not alone. Many people believe that serial killers have no chance for rehabilitation; therefore they should be executed to save money. However, that is where this juror and most of society, generally speaking, are wrong. The death penalty, especially in the case of serial killers, is detrimental and hurts society more than it helps. A life without parole sentence is just as effective, if not more effective, as a deterrent as the death penalty, is economically more efficient and, as Levin stated, serial killers are more cooperative when they are incarcerated for life.

There is more than just a societal bias against serial killers. There is a societal bias and disapproval of the insanity defense. In addition to juror attitudes and misconceptions about the legal aspects of the defense itself, jurors’ implicit theories about what constitutes insanity have been found to be strongly associated with verdicts (Krauss & Lieberman, 2009). Thus, verdicts may depend in large part on jurors’ a priori attitudes and conceptions rather than on the legal standard as applied to the evidence (Krauss & Lieberman, 2009). Many studies have shown that the American public overestimates both the use and success of the insanity defense in the courtroom. This overestimation correlates directly to the thoughts of jurors, and can create a serious bias when the insanity defense is properly pled before them. While it is unclear how much jurors’ implicit theories affect their verdicts, several studies have implicated that jurors may categorize defendants according to prototypes that match their implicit theories of insanity defendants (Krauss & Lieberman, 2009).

With history as an example, public opinion affects laws and customs. The perfect example of a negative public opinion impact is the Reagan assassination attempt. John W. Hinckley, Jr., the man who tried to assassinate Reagan, was acquitted based on the insanity defense and there was a public uproar. As a result of this public outrage, there was major court reform, including the Insanity Defense Reform Act (IDRA), which made it even more difficult to argue the insanity defense.

Furthermore, the statistics brought about by Silver and colleagues (1994) prove that there is a societal bias against the insanity plea. For the .9 percent of felony indictments that result in insanity plea, the public had a 41 times greater estimate at 37 percent (37 per 100 indictments). The public estimated that 44 percent of insanity pleas are successful and result in acquittal when actually only 26 percent result in acquittal. The public estimated that only 50 percent of acquittals result in hospitalization. The actual rate of hospitalization from acquittal is 85 percent. Lastly, the public estimated 26 percent of acquittals lead to freedom. The actual rate of acquittals leading to freedom is 15 percent and if you do not factor in conditional release and outpatient treatment numbers the rate drops to one percent. Although these numbers are from 1994, nevertheless the facts remain the same. The public has a misunderstanding of the use of the insanity plea which impacts jurors who are likely to have the same biases.

Proposal: Psychological Defect Plea

With these societal biases in place, it is nearly impossible for a serial killer to successfully achieve an insanity defense. For the most part, they do not fit the profile and I am not suggesting they should have to. However, it is necessary for these psychological and personality disorders to be addressed and acknowledged from a legal standpoint. As it stands today, these serial killers are being executed or incarcerated in prison for life. Most are not receiving treatment, therapy, and more importantly they are rarely interviewed by criminologists and psychologists for the purpose of learning more about their behavior.

Personality disorders often do not carry much legal weight because they are not considered major mental illnesses (Carter, 2009). Although serial killers, for the most part, seem to possess the capability to know right from wrong, the acts they commit are not always entirely voluntary. If the system were to recognize the inability or the hindrance of voluntary action by psychological disorders, including personality disorders, serial killers could be charged with their crimes and the state could acknowledge their psychological issues. With a psychological defect plea in place, those affected could receive treatment either as an inpatient at a mental hospital or in the facility where they are incarcerated. They would also be subject to mandatory behavioral studies by criminologists and psychologists for further understanding of their diseases and crimes.


Apsche, J.A. (1993). Probing the mind of a serial killer. Morrisville, PA: International Information Associates, Inc.

Carter, S.B. (2009). Justice for all: challenges of the mentally ill in the legal system. Louisville, CO: National Institute for Trial Advocacy.

DeFronzo, J., Ditta, A., Hannon, L., & Prochnow, J. (2007). Male serial homicide: the influence of structural and cultural variables. Homicide Studies, 11(1), 3-14.

Knight, Z.G. (2007). Sexually motivated serial killers and the psychology of aggression and "evil" within a contemporary psychoanalytical perspective. Journal of Sexual Aggression, 13(1), 21-35.

Krauss, D.A., & Lieberman, J.D. (2009). Psychological expertise in court. Burlington, VT: Ashgate Publishing Company.

Levin, J. (2008). Serial killers and sadistic murderers up close and personal. Amherst, NY: Prometheus Books.

Mueller, R.S. (2005, September). Serial murder: multi-disciplinary perspectives for investigators. Retrieved from

Revitch, E., & Schlesinger, L.B. (1981). Psychopathology of homicide. Springfield, IL: Charles C. Thomas Publisher.

Simons, C.L. (2001). Antisocial personality disorder in serial killers: the thrill of the kill. The Justice Professional, 14(4), 345-356. 

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