So many of the early biological and psychological approaches to criminal behavior were flawed and grounded in societal norms and biases. You may be thinking, what can these fields contribute to our knowledge of crime? While some consider individualistic approaches to criminology to be useless, others have adopted new perspectives in studying the influence of biology and psychology on crime.

Important studies in this field have evolved over time, starting with the family studies in the early 1900s. Most of these, similar to the work Goddard did, were purely observational in nature and were not rigorous. Twin studies and adoption studies became popular throughout the 1900s and allowed us to better analyze the nature versus nurture debate (figure 4.13). For example, Sarnoff Mednick (1984) studied the criminal behavior of adopted boys in Denmark over a couple of decades. He found that criminality of the biological parents had a greater predictive effect on the future offending of biological children than the criminality of adopted parents. However, the strongest predictor of criminality was when both biological and adoptive parents had been convicted of crimes.

Mednick concluded that biological and environmental factors contribute to criminality and that the nature versus nurture dichotomy was actually incorrect. Instead, he argued that the interaction between biology and environment is key in understanding criminal offending. This nature via nurture approach, often referred to as a biosocial approach, is the common perspective among modern researchers and theorists today. Biological or psychological traits may be seen as contributing to behavior or putting someone at a predisposition for certain behaviors (including crime), but most modern theorists do not see biological or psychological traits alone as causing crime.

https://youtu.be/JMlJcOSRX-8

Research on the role of the body, brain, and mind in criminality are expansive, including studies on genetics, hormones, neurotransmitters, chromosomal or sex-linked abnormalities, nutrition and substance use, stress, psychological disorders, traumatic brain injuries (TBIs), and the nervous system. It would be impossible to explore all of this research here, but we will look at a few topics to get an idea of how biological and psychological aspects can become risk factors for crime.

Mental Illness and Crime

People with mental illness are overrepresented in the criminal justice system. To the extent that mental illness leads to behaviors that violate the norms and standards of a particular society, people with mental illness would be expected to have a higher rate of contact with the criminal justice system. Some mental illnesses include criminal behavior as part of their diagnostic criteria, including antisocial personality disorder, psychopathy, psychosis, and substance abuse disorders.

Antisocial personality disorder (ASPD) is the personality disorder most strongly linked with violence. It is defined by a continual remorseless disregard for the rights of others, including repeated criminal acts, impulsiveness, irresponsibility, deceptiveness, and aggression. To be diagnosed with this disorder, the person must have exhibited aspects of antisocial behavior prior to age 15, such as aggression toward people or animals, theft, or property destruction (American Psychiatric Association, 2013). Psychopathy, on the other hand, is characterized by two main factors: 1) interpersonal and emotional traits, such as manipulation, grandiosity, and impaired empathy, and 2) antisocial behavior and lifestyle traits, such as impulsive behavior, sensation seeking, and a parasitic lifestyle. Research generally indicates that psychopathy involves brain-based differences that impact emotional and cognitive functioning. It is associated with high reoffending rates and treatment resistance. If you want to learn more about a researcher with a “psychopathic brain,” read or listen to “The Scientist and the Psychopath” [Website].

Psychosis is a condition that impacts how your brain processes information and is present in some severe mental illnesses, including schizophrenia, and mood disorders, such as depression and bipolar disorder. The vast majority of individuals experiencing breaks from the shared reality of the general population do not engage in aggressive or criminal behavior. In fact, people with mental disorders are more likely to be victims of violence than perpetrators (Elbogen & Johnson, 2009). Psychosis can generate specific hallucinations, such as hearing voices or seeing things that do not exist, and delusions, during which a person experiences strongly held but false beliefs that may include paranoid ideas about being persecuted (American Psychiatric Association, 2013). In rare cases, the nature of the hallucination or delusion can lead to inappropriate self-defense or other criminal behavior that would be understandable in light of the beliefs held during a psychotic break. Although some psychosis can lead to violent behavior, far more often, people with active mental illnesses are charged with minor offenses that begin a long cycle of involvement with criminal justice systems.

Finally, substance abuse disorders are characterized by difficulties reducing substance use, thus causing problems in one’s personal and work life (American Psychiatric Association, 2013). Aside from the criminal behavior inherent in prohibited substance use, the tripartite conceptual model (Goldstein, 1985) outlines three main ways that substance use is connected to violent criminal behavior:

• Systemic crime: Related to the drug trade, including selling drugs and the associated violence
• Economically compulsive crime: Results from people engaging in money-making crime to support their substance use
• Psychopharmacologically-driven crime: Occurs when the substance itself affects the brain and behavior, resulting in crime or violence

Today, the Diagnostic and Statistical Manual of Mental Disorders (DSM–5; American Psychiatric Association, 2013) is used in North America to diagnose mental disorders. The DSM-5 describes mental disorders, their symptoms, and the criteria for diagnosing them. However, as most research that informs the DSM-5 has involved predominantly white Americans, it is acknowledged that there is limited evidence of the cross-cultural validity of the DSM-5. Furthermore, connections between mental illness and crime are never direct lines, and may simply be another risk factor among many.

Biology and Crime

As behavior is highly complex, in almost all cases, a behavioral trait will be influenced by a large number of genes, not just two or three. Therefore, “a gene for crime,” or for any complex behavior, cannot exist. However, some traits that predispose one to potentially criminal behavior (e.g., low self-control), might be passed down from parent to child. Additionally, the brain controls all behavior, and we are beginning to understand how imbalances in certain brain chemicals can affect health and behavior. For example, low levels of serotonin, a behavioral inhibitor that regulates the stress response in the brain, have been linked to impulsive-aggressive behavior. People with a head injury that causes damage to their frontal lobe often lose their social graces, self-control, and patience, and they may experience personality changes, develop anxiety or depression, demand instant gratification, or have poor planning skills (Lane et al., 2017). Child abuse commonly results in head injury, and even a mild traumatic brain injury (TBI) may result in lasting behavioral change.

A consistent finding in crime studies is a gender difference in offending behavior. Generally speaking, men commit more crime, especially violent crime, than women. There are many ways to assess this difference; some are specifically related to gender (sociological explanations) and others are related to sex and hormones (biological). For example, testosterone, a male sex hormone, has long been associated with impulsive and violent behavior. Newer research also finds that cortisol, the stress hormone, may be related to criminal offending as well (Armstrong et al., 2022). While some studies suggest that the level of hormones like testosterone is associated with criminal behavior regardless of gender (Dabbs & Hargrove, 1997), sociological understandings also point to society’s expectations and socialization of boys and girls, factors we will explore more in later chapters.

Activity: Policy Case Study—Adam Lanza

In 2012, 20-year-old Adam Lanza shot and killed his mother before going to Sandy Hook Elementary School in Newtown, Connecticut, and killing 20 first-graders and six adults (figure 4.14). He died by suicide shortly after the tragedy.

As a child, Adam struggled with development in language, communication, and sensory processing. He also exhibited repetitive behaviors and motor difficulties. Reports show discussion of autism spectrum disorder (sensory processing disorder), anxiety, and obsessive-compulsive disorder. Classmates described him as socially awkward and “fidgety,” and he could not stand to be touched or near other kids in the classroom.

Throughout his childhood, he had bouts of bad mental health, but mental health professionals who worked with him did not indicate that he would be a threat to others. His parents divorced when he was 16, and about a year later, Adam quit talking to his father. His mental and physical health started to deteriorate again after he graduated from high school. At the time of the shooting, Adam was 6 feet (182.9 cm) tall and weighed 112 pounds (50.8 kg).

After the shooting, police learned that Adam had obsessions with mass murder, cannibalism, and taxidermy that had intensified when he joined obscure online communities. Before committing the mass shooting spree, his internet activity included checking the school’s security measures, indicating that the crime was planned. His family had guns, and he had grown up going to the range with his father so he knew how to use the weapons.

Questions to contemplate and discuss:

• In what ways might our understanding of both biological and psychological factors in offending behavior help us have a more comprehensive picture of Adam Lanza’s actions?
• What ethical considerations come into play when analyzing biological and psychological factors in a case like this one?
• How might our treatment of cases such as this one impact stigma around mental health and/or disability?
• How should we balance the need for public safety with the rights and treatment of people who may exhibit concerning behaviors?
• What preventative measures or actions could be taken to address the interplay of biological and psychological factors in potential future cases?

(Koughan, 2013; Breslow, 2013).

Check Your Knowledge

Licenses and Attributions for Modern Application: How Is It Relevant Now?

Open Content, Original

“Modern Application: How is it Relevant Now?” by Jessica René Peterson is licensed under CC BY 4.0.

“Modern Application: How is it Relevant Now? Question Set” was created by ChatGPT and is not subject to copyright. Edits for relevance, alignment, and meaningful answer feedback by Colleen Sanders are licensed under CC BY 4.0.

Open Content, Shared Previously

“Mental Illness and Crime” is adapted from “Medical Model of Psychopathology and Criminal Behaviour,” Introduction to Criminology by Dr. Jennifer Mervyn and Stacy Ashton, M.A. which is licensed under CC BY 4.0, except where otherwise noted. Modifications by Jessica René Peterson, licensed under CC BY 4.0, include shortening for clarity and brevity and tailoring to the American context.

“Biology and Crime” is adapted from:

• “Genetics,” Introduction to Criminology by Dr. Gail Anderson is licensed under CC BY 4.0, except where otherwise noted. Modifications by Jessica René Peterson, licensed under CC BY 4.0, include shortening for clarity and brevity and tailoring to the American context.
• “Brain Chemistry,” Introduction to Criminology by Dr. Gail Anderson is licensed under CC BY 4.0, except where otherwise noted. Modifications by Jessica René Peterson, licensed under CC BY 4.0, include shortening for clarity and brevity and tailoring to the American context.
• “Brain Damage,” Introduction to Criminology by Dr. Gail Anderson is licensed under CC BY 4.0, except where otherwise noted. Modifications by Jessica René Peterson, licensed under CC BY 4.0, include shortening for clarity and brevity and tailoring to the American context.

All Rights Reserved Content

Figure 4.13. “What identical twins separated at birth teach us about genetics” by BBC is licensed under the Standard YouTube License.

Figure 4.14. Photo by PBS Frontline is included under fair use.