What are psychopaths made of? It’s definitely not sugar and spice and everything nice, and probably not even snips and snails and puppy dog tails. Is it violence and aggression and defiance? That’s what psychopaths are made of. At least, that’s how they behave. And, new research sheds light on brain structure that could explain the violent behavior and seeming lack of conscience.

Most violent crimes are committed by a small, consistent group of males who display antisocial behaviors like hostility, aggression, and defiance of authority. Until recently, this subset of criminals seemed rather heterogeneous, but new evidence points out that the men who commit heinous crimes may be united by structural abnormalities of the brain, specifically, less gray matter where it counts for determining moral actions.

Researchers in Britain examined the brains of violent offenders and non-offenders using magnetic resonance imaging (MRI). In all, they evaluated the brains of 66 men: 17 violent offenders with antisocial personality disorder and the syndrome of pathology, which includes traits such as callousness, selfishness, arrogance, impulsiveness, irresponsibility, and hedonistic tendencies, 27 violent offenders with only antisocial personality disorder, and 22 non-offenders with no mental health diagnoses. The crimes of the offenders included murder, rape, attempted murder, and bodily harm.

The brains of psychopaths showed less gray matter in the anterior rostral prefrontal cortex and temporal poles. These areas of the brain are activated when people think about moral behavior and they are responsible for empathy and understanding other people’s emotions and intentions. They also influence a response to fear and self-conscious emotions such as guilt, embarrassment, and remorse. The offenders without the pathology had gray matter volumes similar to non-offenders.

The findings, published in the Archives of General Psychiatry, point to a distinct neurodevelopmental brain disorder involved in psychopathy. Many criminals meet the criteria for a diagnosis of antisocial personality disorder, with nearly 50% of prisoners in dozens of countries around the world exhibiting such behaviors. But, psychopaths take these behaviors further, engaging in a broader range and greater density of violence. Psychopaths start committing crimes at a younger age than those with only antisocial personality disorder, and they respond less well to treatment. Psychopaths are also separated from those with antisocial disorders, because the latter is evaluated as a pattern of behaviors, while the former is a set of character traits. In lay terms, individuals with antisocial personality disorder may be called “hot heads,” but psychopaths are “cold hearted.”

The implications of the structural MRI findings may be far-reaching. Not only can the results inspire future research into the etiology of violence, but they will likely generate new treatment options. Still, one area that is questionable (even worrisome) is the legal ramifications of such discoveries. Will insanity defenses require MRI scans? Will people be held responsible for their crimes if the structure of their brain made them do it? Ideally, the results of the study can help discover, predict, and, hopefully, prevent, but not excuse, psychopathic behavior.

References

Gregory S, Ffytche D, Simmons A, Kumari V, Howard M, Hodgins S, & Blackwood N (2012). The Antisocial Brain: Psychopathy Matters: A Structural MRI Investigation of Antisocial Male Violent Offenders. Archives of general psychiatry PMID: 22566562

Tiihonen J, Rossi R, Laakso MP, Hodgins S, Testa C, Perez J, Repo-Tiihonen E, Vaurio O, Soininen H, Aronen HJ, Könönen M, Thompson PM, & Frisoni GB (2008). Brain anatomy of persistent violent offenders: more rather than less. Psychiatry research, 163 (3), 201-12 PMID: 18662866

Yang Y, & Raine A (2009). Prefrontal structural and functional brain imaging findings in antisocial, violent, and psychopathic individuals: a meta-analysis. Psychiatry research, 174 (2), 81-8 PMID: 19833485

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