Resting state functional magnetic resonance imaging study in mentally ill persons with diminished penal responsibility considered socially dangerous

The relation between mental illness and criminality is a relevant social issue that has been debated over the years. Modern neuroimaging investigations support the joint efforts of psychiatrists and lawyers to study the relationship between psychiatric illness and criminality. In this study we investigated brain networks underpinning moral behaviour, salience attribution and reward processes performing a functional MRI at resting-state in a population of 13 right-handed males institutionalized in the psychiatric unit of a residence for the execution of security measure in Italy. Thirteen healthy right-handed men, who had never received a psychiatric diagnosis, undergone any psychiatric treatment, or been convicted of any crime were included in the control group, matched for age and sex. Our results documented aberrant connectivity of the striatum with brain regions linked to reward processing and emotionality. Particulary, the ventral striatum showed reduced connectivity with the amygdala and increased connectivity with the posterior cingulate cortex. We also found alterations in key structures for sensory integration, modulation of autonomic reactions and participation in learning, prediction, and decision making like the fronto-orbitalis cortex and the anterior cingulate cortex, that results hyperconnected respectively with basal ganglia and amygdala. We suggest that connectivity dysregulation in brain network subserving morality, salience and reward reflects the maladaptive behavior in terms of altered emotional response in decision-making and in reward processes in mentally ill persons socially dangerous. A further understanding of the neural basis of risk evaluation in these individuals could aid in forensic assessment and treatment development.