Aggression is highly prevalent in borderline personality disorder (BPD). Previous studies have identified specific biobehavioral mechanisms underlying aggression in BPD, threat sensitivity being among them. We composited the mechanism-based anti-aggression psychotherapy (MAAP) in order to target these specific mechanisms, and MAAP was found to be superior to non-specific supportive psychotherapy (NSSP) in reducing aggressive behavior. In the present study, we investigated whether underlying brain mechanisms expected to be involved were affected by MAAP. To this end, n = 33 patients with BPD and overt aggressive behavior (n = 20 in MAAP, n = 13 in NSSP) and n = 25 healthy participants took part in a functional magnetic resonance imaging emotional face-matching task before and after treatment, or at a similar time interval for controls. Overt aggressive behavior was assessed using the overt aggression scale, modified. Results showed a decrease in amygdala activation in response to facial stimuli after MAAP, whereas an increase in amygdala activation was found after NSSP. Furthermore, in the MAAP group, connectivity between amygdala and dorsomedial prefrontal cortex increased from pre- to post-treatment compared to the NSSP group. Hence, the results suggest an impact of MAAP on brain mechanisms underlying the salience circuit in response to threat cues.

Aggression is a prominent interpersonal dysfunction of individuals with borderline personality disorder (BPD). In BPD aggression is predominantly reactive in nature, often triggered by frustration, provocation, or social threat and is associated with intense anger and an inability to regulate this strong, negative emotion. Building on previous research, we were interested in investigating negative emotionality in general and anger in particular in women with BPD before and after frustration induction. To achieve this, 60 medication-free women with BPD and 32 healthy women rated the intensity of negative emotions (angry, frustrated, upset, embarrassed, nervous) before and after performing a Titrated Mirror Tracing Task, which reliably induces frustration and distress. As expected, women with BPD reported significantly greater intensity of negative emotions before and after frustration than healthy women. Specifically, they showed a significantly stronger frustration-induced increase in anger, while other negative emotions remained unaffected by frustration induction. This anger increase was significantly related to aggressive behavior reported in the 2 weeks prior to the experiment, as well as to the level of frustration experienced in the experiment itself, but not with emotion dysregulation. The current data confirm the important role of frustration-induced anger independent of emotion dysregulation in BPD, in particular with regard to aggression, a prominent interpersonal dysfunction of this disorder. These findings underline the importance of interventions with particular focus on anger.

Introduction: Aggressive behavior is highly prevalent in patients with borderline personality disorder (BPD) and represents a major burden for patients and their environment. Previous studies have hypothesized threat hypersensitivity, among other mechanisms, as a biobehavioral mechanism underlying aggressive behavior in patients with BPD. The effects of a 6-week mechanism-based anti-aggression psychotherapy (MAAP) for the group setting were tested in comparison to the effects of a non-specific supportive psychotherapy (NSSP) on this hypothesized mechanism and their relation to the effects on aggressive behavior.Methods: To assess mechanisms of reactive aggression, 38 patients with BPD (20 in MAAP and 18 in NSSP) and 24 healthy controls participated in an emotion classification task before and after therapy or at a similar interval of 7 weeks for controls, respectively. In addition, current reactive aggressive behavior was assessed by the externally directed overt aggression score of the Overt Aggression Scale Modified (OAS-M) at both time points. Mixed linear models were used to test for group differences and differential treatment effects.Results: Consistent with previous findings, patients showed longer response latencies and misclassified faces as angry more often than healthy controls. Comparing pre- and post-treatment measurements, the MAAP group showed an increase in response latency in classifying angry faces, whereas the NSSP group showed a decrease in latency. Furthermore, the difference between pre- and post-treatment response latencies in classifying emotional faces correlated with the reductions in reactive aggression in the MAAP group, but not in the NSSP group or healthy controls.Conclusion: The results suggest an impact of MAAP on threat sensitivity as well as cognitive control, which has also been previously hypothesized as a biobehavioral mechanism underlying reactive aggression in patients with BPD. In addition, our findings shed light on the importance of these two biobehavioral mechanisms underlying reactive aggression as mechanisms of change addressed by MAAP. Further studies are needed to determine whether the behavioral change is stable over time and to what extent this change is related to a stable reduction in reactive aggression in a larger group of patients with BPD.