Discussion
anger, HC, ASPD, psychopathy, aggression, psychiatric
DYSFUNCTION, STILL, DISORDERS
Oxytocin (OT) has been proposed to be beneficial to several psychiatric disorders characterized by social dysfunction by modulating the amygdala during facial emotion recognition [Consistent with our earlier findings obtained with an overlapping sample [Under PLC, we found a stronger right amygdala activation in ASPD vs. HC participants for angry faces when the mouth region was initially presented. This is in line with the executive emotion model, in which increased amygdala responsiveness to threat cues (e.g., angry faces) might lead to reactive aggression [After OT administration, we found a decreased right amygdala activity for angry and happy faces in the ASPD group and an increased right amygdala activity for fearful faces in the HC group. Most interesting was the effect of OT on amygdala activation to angry faces: The activation pattern of ASPD and HC were opposite in the OT condition compared to the PLC condition. This group difference in OT effect is in line with the social salience hypothesis [There is evidence of hormonal cycle-related OT effects on emotion recognition accuracy in healthy young females [Although ASPD is prevalent in males and females, most studies have exclusively focused on males [One strength of this study is the largest ASPD sample in the fMRI literature [Even though the sample size is comparably large, it is limited since we explored up to six-way interactions. Still, we found group effects on amygdala activation which speaks for a validity of our results. Furthermore, we did not have a clinical control group. A significant proportion of the ASPD sample met criteria for psychopathy. However, we decided to be cautious with correlation analyses due to the small sample (9 individuals of 20 male ASPD participants, 7 individuals of 18 female ASPD participants) and the fact that the SRP score has not been a target variable. Yet, the differences between ASPD and psychopathy in emotion classification tasks are not well understood, calling for further studies with larger sample sizes. Second, due to lack of compliance of individuals with ASPD, we resigned from controlling the phase of the menstrual cycle though research indicates that amygdala function in females differs between different phases of their menstrual cycle [In conclusion, data from this study showed that OT has a specific effect on anger-related amygdala activity in ASPD. OT was found to dampen amygdala activity in response to angry faces that are highly salient for individuals with ASPD and high trait anger especially in ASPD women compared to ASPD men. These findings suggest that attenuating the salience of cues perceived as threatening or provoking, is promising in the treatment of reactive aggression in ASPD patients, particularly when they are females.