A new study has found that psychopaths show structural changes in particular areas of the brain that deal with things like impulse control and emotional regulation. This improved understanding may help to formulate targeted treatment and rehabilitation strategies.
Psychopaths appear to be walking contradictions, exhibiting (sometimes extreme) antisocial behavior while staying on the right side of a diagnosis of “insanity.” But as one of the strongest predictors of aggressive and violent behavior, it’s important to be able to accurately diagnose psychopathy, especially in the forensic setting.
A new study by US and German researchers has provided a greater understanding of psychopathy, using advanced brain imaging to pinpoint the structural changes that occur in the brains of individuals diagnosed with psychopathy.
The researchers focused on whether different psychopathic traits could be mapped to different brain regions. Psychopathy was measured using the Psychopathy Checklist-Revised (PCL-R), a 20-item scale scored from interview and file information, which has two main parts:
- Factor 1: Emotional detachment (e.g., lack of guilt or empathy, superficial charm, manipulativeness).
- Factor 2: Antisocial behavior (e.g., deviance from an early age, aggression, impulsivity, irresponsibility, proneness to boredom).
The 20 items are rated on a three-point scale, from zero to two, based on the degree to which the personality or behavior of the subject matches the item description, which then yields a total score. For the present study, the researchers selected 39 males with a PCL-R score of 20 or higher from German forensic institutions, including prisons and secure psychiatric hospitals. They were matched with non-psychopathic control subjects. All participants underwent MRI brain scans. The volumes of different brain regions were analyzed using detailed anatomical atlases of the brain, and statistical models were used to examine the relationships between brain volume and psychopathy scores.
The researchers found that, in relation to Factor 1 of the PCL-R, there were only weak and inconsistent associations with brain structure. A few small brain areas, especially in the orbitofrontal cortex and hippocampus, showed some correlation (both positive and negative), but these results weren’t statistically robust. It suggests that these traits may involve more complex or varied brain circuits or might not reflect structural brain changes at all. Regarding Factor 2, however, there were clear and widespread negative associations with brain volume. The key areas affected included the thalamus, basal ganglia, brainstem, and insular cortex, known to be involved in impulse control, emotional regulation, and behavioral inhibition.
Pieperhoff, P. et al 2025
Psychopathic individuals were found to have a smaller total brain volume, about 1.45% less than non-psychopathic individuals. This was especially so in the cortex, the right subiculum (a part of the hippocampus), the anterior cingulate and insular cortices. These areas are important for social behavior, emotion, and self-control.
The study has some important limitations, including that it only recruited a small number of psychopathic individuals, which limits its statistical power. Although participants were reportedly drug-free for months, the long-term effects of prior substance use may still have influenced brain structure. Intelligence was not measured for all participants, which could confound the results. Participants were scanned at different sites using different MRI machines, although the data analysis tried to adjust for this. The control group’s psychopathy levels weren’t measured using the PCL-R, so the existence of subclinical traits, that is, traits that aren’t outwardly detectable, can’t be ruled out.
Nevertheless, the study findings help reinforce that impulsive and antisocial traits in psychopathy are tied to real, measurable brain differences, particularly in circuits responsible for behavior regulation. Understanding the brain regions associated with different psychopathic traits may support the development of more targeted therapies or rehabilitation strategies. Additionally, having insights into structural abnormalities such as those identified in the study may improve risk assessment for violent or antisocial behavior, especially in forensic settings.
Interestingly, the mixed findings for Factor 1 suggest that some traits might not reflect dysfunction. In other words, things like manipulativeness and low empathy may coexist with higher cognitive functioning in some individuals. This knowledge may improve our understanding of the “successful” psychopath. A question for future research would be to what degree these structural differences are inherited or associated with, for example, environmental factors.
The study was published in the journal European Archives of Psychiatry and Clinical Neuroscience.
Source: eBrains
