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A comparative analysis on murderers, cannibalistic murderers and the psychological factors that drive them

By Anna Vlugt

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Trigger Warning and Disclaimer

The following article contains graphic descriptions of cannibalism as well as discussions regarding mental health and may not be suitable for all readers.  

Furthermore, this article places a large emphasis on mental disorders from a forensic psychology perspective. Please note that this is purely for educational and scientific purposes and is not intended to add to the stigma of mental illnesses. 

Introduction: What is Cannibalism? 

In mythology, fables, and true crime documentaries the term ‘cannibalism’ is used to describe one human consuming the flesh of another human. The correct term for this act, however, is anthropophagy whereas cannibalism is the act of a member of any species consuming one of its own. The latter is an umbrella term referring to humans as well as all other animals. In addition to anthropophagy being a type of cannibalism, there are two additional subsects under the former (Lester, White, & Giordano, 2015). Endocannibalism is the act of consuming the remains of a deceased member of one’s community as a means of honoring them (Merriam-Webster, n.d.). The second type, exocannibalism, is the type of cannibalism most often seen in popular culture. Exocannibalism refers to the consumption of one outside of the offender’s community (almost always someone considered to be an enemy) and is often an act of aggression. Further, it is important to note vampirism (Renfield’s syndrome) as another type of anthropophagy. Vampirism combines aspects of necrophilia, sadism, and an erotic fascination with blood in addition to the cannibalistic aspect of consuming human blood. Schizophrenia and paraphilia are the two most common mental disorders seen in those with vampirism. Although vampirism is a very specific type of cannibalism and rather uncommon, however exocannibalism can be sighted in some well-known criminal cases (Byard, 2023). 

3 Cases of Cannibalism 

Through the course of history endocannibalism became progressively less common, bringing the attention to cases of exocannibalism. One of the best-known cases of cannibalism in modern society is that of Jeffery Dahmer. Easily recognizable by his retro aviator glasses, Dahmer (aka. The Milwaukee Cannibal) has been immortalized in several true crime documentaries and biopics. Dahmer brutally killed and dismembered over a dozen young boys and men in the years he was active. Law enforcement officials were led back to Dahmer’s apartment by a nude man in handcuffs who had escaped from Dahmer’s clutches. The escape was ultimately short-lived, however. Dahmer convinced the police that the man was his lover, leaving Dahmer and the man alone, allowing him to carry through with the murder (FBI, 2016). These facts alone would be enough to write someone off as a sexual sadist with the psychopathy of a killer (both of which Dahmer was diagnosed with). The additional aspects of cannibalism and necrophilia only add to the list of reasons this case is so well-known. The ritualistic behavior of cannibalism only appeared in Dahmer’s later kills; however, it is arguably the best-known aspect of the case. Eventually the police gained access to the apartment and quickly found a decapitated head in the refrigerator. This led to Dahmer’s arrest and a large-scale criminal investigation (Lester & White, 2001). 

Another substantial case of cannibalism involves German citizen Armin Meiwes. This case is notable for several reasons, one of which being that the man Meiwes killed and consumed consented to have this done to him. It went as far as Meiwes obtaining a contract signed by his victim saying Meiwes had the right to murder and eat him. Meiwes and his victim decided that the latter would first be castrated and then the two would consume his genitals together. The victim began to bleed out shortly thereafter resulting in Meiwes killing him and consuming his remains over ten months. The Meiwes case brought up several questions regarding consent, legality, mental health, and criminal responsibility (Stampf, 2006). 

The Donner Party is another well-known example of cannibalism. In this case a group of pioneers migrated to California from the Mid-Western United States during the winter of 1846 to 1847. During their journey, they encountered several delays and issues resulting in them needing to spend the winter in the Sierra Nevada, a mountain range in California and Nevada. Many of the pioneers succumbed to illness, starvation, and the cold, allowing those who survived to consume their remains (McCurdy, 1994). Some believe that the pioneers also murdered and consumed two Native Americans, however this has never been officially proven. The two Native Americans were said to have been attempting to help the members of the party however it is unclear if they were killed upon their arrival or if they never made it there to begin with (Stuckey, 2011). The Donner Party differs from the other two cases as survivability had come into play. However, it is still a relevant case to examine when studying the forensic psychology behind cannibalism. The three cases mentioned above are only a few examples of cannibalistic behavior. The studies based on these cases (and others) have contributed to creating theories for psychologists to use moving forward.  

Psychological Factors 

The consumption of another human’s flesh as a means of survival does not automatically mean the consumer has a mental disorder. In many cases, exocannibalism is linked to extreme mental disorders, however, these disorders are not necessarily a ‘requirement’ to be a cannibal. Simply put, the presence of mental disorders is a correlation, not a causation.  

In the case of Dahmer, a diagnosis of borderline personality disorder, schizotypal personality disorder, and several psychotic disorders were given (Palermo & Bogaerts, 2015). These mental disorders do not necessarily apply to all exocannibals nor does everyone with these disorders become an exocannibal. However, they are a common theme amongst cannibals as well as a few other disorders. 

• Borderline Personality Disorder: 

Borderline Personality Disorder begins to show symptoms in early adulthood and is associated with mood swings, anger, impulsivity, and self-image issues. Other symptoms consist of fear of abandonment, unstable or intense relationships, paranoia, suicidal thoughts or ideations, and a feeling of emptiness (Mayo Clinic, 2022).  

• Schizophrenia: 

Those with schizophrenia often fit into five different categories of symptoms. Delusions are the belief of things that are not based on reality and hallucinations is when a person sees or hears things that are not there (Walsh, 2019, p. 171). The other three symptoms are incoherent speech patterns, unusual movements, and negative behavior, meaning a lack of what are perceived as normal behaviors (e.g. bathing, socializing, etc.) (National Health Service, 2023).  

• Antisocial Personality Disorder: 

More commonly known as ‘psychopaths’, people with antisocial personality disorder can be kind, fun, and charming or liars and con artists (Glenn, Johnson, & Raine, 2013). Symptoms of antisocial personality disorder also consist of rash behavior, irritability, aggressiveness, lack of remorse, disregard of laws and social norms, and a lack of interest in their safety or the safety of others (Patrick, 2022). 

These mental disorders are often found in cannibals. However, there are several other contributing factors that need to be considered. Childhood abuse plays a large role amongst cannibals with studies showing that compared to non-cannibalistic serial killers, cannibals are significantly more likely to have been subject to childhood abuse and were in low-income families. In the case of a 14-year-old girl who was institutionalized for her cannibalistic urges, she did not meet the criteria of any mental disorder but was a victim of severe (sexual) abuse (Oldak et al., 2023). Although mental disorders are found in cannibals more often than not, ‘nurture’ also plays a large role and can be the only factor as well (American Academy of Experts in Traumatic Stress, n.d.) 

Head injuries also can play a role in cannibalistic behavior, especially in auto-cannibalism (the consumption of one’s own flesh). Several studies have been conducted, which show patients with auto-cannibalistic behaviors have also experienced some sort of traumatic brain injury before the auto-cannibalistic behaviors started (Fenati et al., 2023). Head injuries also increase the chances of a person developing antisocial personality disorder (Maresca et al., 2023)​ and schizophrenia (AbdelMalik et al., 2003)​ or can give those who already have these conditions more extreme symptoms (Molloy et al., 2011)​. 

Cannibalism can also stem from a fetish. Sexual cannibalism (vorarephilia) is when the cannibalistic ideations are erotic, and the people involved either want to be consumed by the other or want to consume another (Jesus et al., 2023). These urges can be seen in people as far back as medieval texts. Cannibalism was used as a metaphor for love in these texts and many others because both are said to be ‘all consuming’ and show the pain that comes from love. For those with vorarephilia, cannibalistic behaviors are a sign of love rather than an act of aggression (Schneider, 2014).  

There is no single mental health disorder or other condition that makes someone a cannibal; however, there are several disorders and conditions that are regularly seen in those with cannibalistic tendencies. These disorders and conditions are also common in non-cannibalistic serial killers leaving the question what causes one to cross the line into cannibalism. Further, the different conditions do not necessarily manifest in cannibal offenders the same way. 

Theoretical Tools 

A diagnosis is not the only way (forensic) psychologists can determine if someone has or will have murderous or cannibalistic tendencies. There are several theoretical tools that professionals in psychology and criminology reference in this process as well. One of which is the MacDonald Triad, a theory made to help identify three developmental markers that may indicate a predisposition to killing in their early adolescent years. These markers consist of fire setting during childhood, cruelty towards animals, and wetting the bed after the age of five (Joubert et al., 2021). The presence of the MacDonald Triad in a child is an early indicator of violent behavior when one reaches adulthood. This theory, however, has been debated over time due to the lack of statistical proof (Parfitt & Alleyne, 2020). Other theoretical tools used in criminology to categorize offenders are criminal responsibility, the violent offenders’ categories, and several others. The MacDonald Triad is the theory most relevant to the question at hand. 

Comparative Analysis of Murderers and Cannibalistic Murderers: 

Why do some serial killers stop after the murder whereas others feel the need to take the crime a step further, especially when they may share a mental disorder? As previously mentioned, low socioeconomic status and abuse during an offender’s childhood is a factor that can push someone from killing to cannibalistic killing. Another factor that differs from murderers to cannibalistic murderers is childhood abandonment as the latter has experienced this more than the former (Marono & Keatley, 2022).  

The ‘Green River Killer’ Gary Ridgway was convicted for killing 49 victims, admitted to killing 71, and was suspected of killing 90 or more, making him the killer with the second most victims in the United States (Chan, 2019). Ridgway showed signs from the MacDonald triad such as wetting the bed well into his teen years. Further, Ridgway had occasionally faced corporal punishment from his mother but no other signs of (sexual) abuse were reported (Piccotti & Bertram, 2023). Furthermore, he was dyslexic and has been described as having a low IQ. Although his childhood was troubled, there are no major signs of abuse, sans the corporal punishment, nor was he abandoned, and the family was financially stable (King County Sheriff’s Office, n.d.).  

This is a stark contrast to the childhood of Jeffery Dahmer. After undergoing a double hernia surgery at the age of four, Dahmer’s life began to go ‘downhill’. In interviews, Dahmer stated that when he woke up from the surgery, he was terrified that he had been castrated. Some have since speculated that this is a contributing factor into why he later castrated his victims (Dağoğlu, 2024). A victim of sexual abuse at the hands of a neighbor, Dahmer also was abandoned after his parents’ divorce (Higgs, 2012). His father left and his mother took custody of his younger brother, but no parent was willing to take custody of Dahmer resulting in him being alone and unmonitored. Dahmer was also said to have been somewhat ignored his whole life due to his parents’ difficult marriage. The family was also not in a stable financial situation as his mother was a drug addict and his father was a student. The MacDonald Triad can also be seen in Dahmer’s childhood. He has shown cruelty to animals by pouring motor oil into a tank of tadpoles, had a fascination with dead animals resulting in him picking up the skills of a taxidermist, and allegedly decapitated a dog (People for the Ethical Treatment of Animals, n.d.). Based on the information from studies stating abuse and economic hardship in one’s childhood would make them more likely to be a cannibalistic killer, Dahmer is a textbook fit (University of Northampton, 2022).  

It is important to note that a killer who was well-off in childhood financially, safe from abuse, and was never abandoned can still become a cannibal, as is true for the opposite. There is no foolproof way to determine if someone will become a killer, let alone a cannibalistic one. Amongst cannibalistic killers, there is a significant amount of consistency between their respective childhoods. Psychologists and forensic scientists may never actually know what specifically causes cannibalism, but there is enough information about cannibals to create a working profile. 

Comparative Analysis of Cannibalistic Murderers with Different Mental Disorders 

Within murderers who do partake in cannibalistic activities, there are differences between them based on their mental disorder. A study completed in France focused on five cannibalistic murderers in a psychiatric ward with researchers placing them into two subgroups based on their mental disorder. Subgroup one consisted of cannibals with severe schizophrenia. The patients that fell into this group committed acts of cannibalism as self-defense. Due to the hallucinations and delusions that come with schizophrenia, the cannibalistic killers with this disorder view others as a threat and the only way to eliminate that threat, is by killing and consuming them (Raymond, 2023). 

The second subgroup holds the cannibals with mixed personality disorder, sadistic and psychopathic tendencies as well as paraphilia. They struggle with a narcissistic personality and cannibalism allowed them to feel superior and gain an ‘ego boost’. The patients in this subgroup shared the feeling that by consuming someone, it makes the victim inferior. These patients were also much more methodical with their murders and consumption, involving a sexual aspect that could not be found in the murders from subgroup one (Raymond, 2023).  

Conclusion: 

The human mind contains more than a quadrillion synapses, and as of 2023 the top neuroscientists have still yet to create a full theory on how the brain functions (Allen Institute, 2022). Forensic psychology can only answer so many questions about cannibalistic killers, but from the information that has been discovered, forensic psychologists have been able to create several working theories (Roland, 2023). Although the theories of forensic psychologists will continue to develop, it is almost impossible that a complete list of indicators that determine if someone will become a cannibal will be created.  

For this reason, forensic psychologists need to rely on the differences in the upbringings of cannibalistic and non-cannibalistic killers as key indicators when understanding what brings a person to commit such crimes. By understanding and comparing the childhoods and actions of known cannibals and non-cannibalistic killers, one can begin to draw conclusions on what ‘makes’ someone a cannibal. These are simply theories with statistical support. Just because someone had a similar childhood to Dahmer or a childhood containing features from a list of indicators, does not mean they will become a murderer or cannibal. For someone to become a cannibal there must be intrinsic factors (‘nature’) in addition to the ‘nurture’. By analyzing the mental disorders and brain functions of cannibals and other offenders, it is possible to identify patterns.  

These two factors both play a key role in the understanding of cannibalistic killers as well as other factors psychologists have yet to discover. In future studies, one might want to further analyze the prenatal history of known cannibals and non-cannibalistic killers to identify if there is a difference between the two regarding mothers who, smoked, drank, or were under large amounts of stress during their pregnancy. Further, more comparative studies between known cannibals with a larger sample population may lead to more accurate results.  

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Reference List and Additional Sources

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