Disentangling structural brain alterations associated with violent behavior from those associated with substance use...

Area of Science:

• Neuroscience
• Forensic Psychiatry
• Addiction Research

Background:

• Previous studies on violent behavior and psychopathy often overlooked lifetime substance misuse.
• Structural brain alterations linked to violence may be influenced by substance use disorders (SUDs).

Purpose of the Study:

• To differentiate gray matter (GM) volume alterations associated with violent behavior from those linked to lifelong SUDs.
• To investigate the neurobiological underpinnings of violence and SUDs separately.

Main Methods:

• Cross-sectional study comparing four groups of men: violent offenders with/without SUDs and nonoffenders with/without SUDs.
• Voxel-based morphometry analysis of high-resolution MRI scans.
• Clinical assessments of mental disorders, psychopathy, aggression, and impulsivity.

Main Results:

• Violent offenders exhibited larger GM volume in the amygdala, nucleus accumbens, and caudate head, and reduced volume in the insula compared to nonoffenders.
• Men with SUDs showed smaller GM volume in the orbitofrontal cortex, ventromedial prefrontal cortex, and premotor cortex.
• GM alterations in violent offenders correlated with psychopathy and aggression scores; SUD-related GM changes correlated with response inhibition.

Conclusions:

• Increased GM volume in the mesolimbic reward system may be associated with violent behavior.
• Reduced GM volumes in the prefrontal cortex, orbitofrontal cortex, and premotor areas characterize individuals with SUDs.
• Findings highlight distinct neurobiological correlates for violent behavior and SUDs.