There is increasing evidence for a neurobiological basis of antisocial personality disorder (ASPD), includinggenetic liability, aberrant serotonergic function, neuropsychological deficits and structural and functional brain abnormalities. However, few functional brain imaging studies have been conducted using tasks of clinically relevant functions such as impulse control and reinforcement processing. Here we report on a study investigating the neural basis of behavioural inhibition and reward sensitivity in ASPD using functional magnetic resonance imaging (fMRI).

17 medication-free male individuals with DSM IV ASPD and 14 healthy controls were included. All subjects were screened for Axis I pathology and substance misuse. Scanner tasks included two block design tasks: one Go/No-Go task and one reward task. Scanning was carried out on a 1.5T Phillips system. Whole brain coverage was achieved using 40 axial slices with 3.5mm spacing a TR of 5 seconds. Data were analysed using SPM5 using random effects models.

Results of the Go/No-Go task confirmed brain activation previously described in the processing of impulse inhibition, namely in the orbitofrontal and dorsolateral prefrontal cortex and the anterior cingulate, and these were enhanced in the PD group. The reward task was associated with BOLD response changes in the reward network in both groups. However, these BOLD responses were reduced in the ASPD group, particularly in prefrontal areas.

Our results further support the notion of prefrontal dysfunction in ASPD. However, contrary to previous studies suggesting “hypofrontality” in this disorder, we found task specific increased and decreased BOLD responses.