Psychopaths impose large costs on society, as they are frequently habitual, violent criminals. The pervasive nature of emotional and behavioral symptoms in psychopathy suggests that several associated brain regions may contribute to the disorder. Studies employing a variety of methods have converged on a set of brain regions in paralimbic cortex and limbic areas that appear to be dysfunctional in psychopathy. The present study further tests this hypothesis by investigating structural abnormalities using voxel-based morphometry in a sample of incarcerated men (N [H11005] 296). Psychopathy was associated with decreased regional gray matter in several paralimbic and limbic areas, including bilateral parahippocampal, amygdala, and hippocampal regions, bilateral temporal pole, posterior cingulate cortex, and orbitofrontal cortex. The consistent identification of paralimbic cortex and limbic structures in psychopathy across diverse methodologies strengthens the interpretation that these regions are crucial for understanding neural dysfunction in psychopathy.

Objective To investigate the relationship between brain structure and psychopathic traits in maximum-security incarcerated male adolescents: Do the associations between brain volumes in paralimbic and limbic regions and psychopathic traits observed in incarcerated adult men extend to an independent sample of incarcerated male adolescents? Method A structural magnetic resonance imaging (MRI) study of regional gray matter volumes (GMV) by using voxel-based morphometry (VBM) in maximum-security incarcerated male adolescents (N=218) assessed for psychopathic traits using the Hare Psychopathy Checklist–Youth Version (PCL-YV). All analyses controlled for effects of age, substance use, and brain size. Results Consistent with hypotheses and the adult literature, psychopathic traits were associated with decreased regional GMV in diffuse paralimbic regions, including orbitofrontal cortex, bilateral temporal poles, and posterior cingulate cortex. Conclusions These results strengthen the interpretation that paralimbic regions are central for understanding neural dysfunction associated with psychopathic traits and that psychopathy is best conceptualized as a neurodevelopmental disorder.

Importance Marijuana use may alter ventral striatal response to reward, which may heighten susceptibility to substance use disorder (SUD). Cross-sectional studies have reported either increased ventral striatal response to reward or no difference in marijuana users compared with controls. Longitudinal research is needed to resolve the inconsistencies and disentangle preexisting susceptibility from the effects of marijuana use on neural function involved in reward responding. Objective To determine whether marijuana use among young adults prospectively impacts nucleus accumbens (NAcc) activation during reward anticipation. Design Longitudinal study of self-report marijuana use and brain function using functional magnetic resonance imaging (fMRI) at three consecutive time points. Setting Data were obtained from young adult participants in the Michigan Longitudinal Study, an ongoing, prospective study of youth at high risk for SUD and a contrast sample of control families. Participants The sample consisted of 108 young adults (36% female; 78% family history of SUD) who underwent three fMRI scans at approximately age 20 (time 1), 22 (time 2), and 24 (time 3). Main Outcome and Measures We investigated the impact of marijuana use on neural response in the NAcc to reward anticipation during a monetary incentive delay task (MIDT) using a cross-lagged model. Covariates for analyses included sex, age at first scan, family history of SUD, prior marijuana use, and binge drinking (prior and concurrent). This model was also tested separately with the inclusion of cigarette smoking. Results Greater marijuana use was associated with later blunted activation in the NAcc during reward anticipation (time 1 to time 2: β=−0.26, P=0.04; time 2 to time 3: β=−0.25, P=0.01). When we tested the cross-lagged model with the inclusion of prior and concurrent cigarette use, the impact of marijuana use from time 2 to time 3 remained significant and the effect of cigarette use was non-significant. Conclusions and Relevance Our findings indicate that marijuana use is associated with decreased neural response in the NAcc during the anticipation of non-drug rewards. Over time, marijuana use may alter anticipatory reward processing in the NAcc, which may increase risk for continued drug use and later addiction.

Psychopathy-related paralimbic and limbic structural brain abnormalities have been implicated in incarcerated adult and adolescent male samples. However, there have been few neuroimaging studies of psychopathic traits in females in general and no studies from incarcerated female youth in particular. Here we present the first study to examine the relationship between brain gray matter volumes and psychopathic traits (assessed using the Psychopathy Checklist-Youth Version [PCL-YV]) in a sample of maximum-security incarcerated female adolescents (N = 39; mean age = 17.6 years). Consistent with male samples, regional gray matter volumes were negatively related to psychopathic traits in female youth offenders in limbic and paralimbic areas, including orbitofrontal cortex, parahippocampal cortex, temporal poles, and left hippocampus. These results provide evidence that psychopathic traits manifest similar neural abnormalities across sex and age.