BACKGROUND - Disturbed interpersonal relations and emotional dysregulation are fundamental aspects of borderline personality disorder (BPD). The amygdala plays important roles in modulating vigilance and generating negative emotional states and is often abnormally reactive in disorders of mood and emotion. The aim of this study was to assess amygdala reactivity in BPD patients relative to normal control subjects. We hypothesized that amygdala hyperreactivity contributes to hypervigilance, emotional dysregulation, and disturbed interpersonal relations in BPD.
METHODS - Using functional magnetic resonance imaging, we examined neural responses to 20-sec blocks of neutral, happy, sad, and fearful facial expression (or a fixation point) in 15 BPD and 15 normal control subjects. The DSM IV-diagnosed BPD patients and the normal control subjects were assessed by a clinical research team in a medical school psychiatry department.
RESULTS - Borderline patients showed significantly greater left amygdala activation to the facial expressions of emotion (vs. a fixation point) compared with normal control subjects. Post-scan debriefing revealed that some borderline patients had difficulty disambiguating neutral faces or found them threatening.
CONCLUSIONS - Pictures of human emotional expressions elicit robust differences in amygdala activation levels in borderline patients, compared with normal control subjects, and can be used as probes to study the neuropathophysiologic basis of borderline personality disorder.