Laboratory Induced Aggression: A Positron Emission Tomography Study of Aggressive Individuals with Borderline Personality Disorder

Background: Borderline personality disorder (BPD) is often associated with symptoms of impulsive aggression, which poses a threat to patients themselves and to others. Preclinical studies show that orbital frontal cortex (OFC) plays a role in regulating impulsive aggression. Prior work has found OFC dysfunction in BPD. Methods: We employed a task to provoke aggressive behavior, the Point Subtraction Aggression Paradigm (PSAP), which has never previously been used during functional brain imaging. Thirty-eight BPD patients with intermittent explosive disorder (BPD-IED) and 36 age-matched healthy control subjects (HCs) received ¹⁸fluoro-deoxyglucose positron emission tomography (¹⁸FDG-PET) on two occasions with a provocation and nonprovocation version of the PSAP. Mean relative glucose metabolism was measured throughout the cortex, and difference scores (provoked - nonprovoked) were calculated. A whole brain exploratory analysis for the double difference of BPD-IED - HC for provoked - nonprovoked was also conducted. Results: BPD-IED patients were significantly more aggressive than HCs on the PSAP. BPD-IED patients also increased relative glucose metabolic rate (rGMR) in OFC and amygdala when provoked, while HCs decreased rGMR in these areas. However, HCs increased rGMR in anterior, medial, and dorsolateral prefrontal regions during provocation more than BPD-IED patients. Conclusions: Patients responded aggressively and showed heightened rGMR in emotional brain areas, including amygdala and OFC, in response to provocation but not in more dorsal brain regions associated with cognitive control of aggression. In contrast, HCs increased rGMR in dorsal regions of PFC during aggression provocation, brain regions involved in top-down cognitive control of aggression, and, more broadly, of emotion.