Potentiated amygdala response to repeated emotional pictures in borderline personality disorder

Background: Borderline personality disorder (BPD) is characterized by an inability to regulate emotional responses. The amygdala is important in learning about the valence (goodness and badness) of stimuli and functions abnormally in BPD.

Methods: Event-related functional magnetic resonance imaging (MRI) was employed in three groups: unmedicated BPD (n = 33) and schizotypal personality disorder (n = 28) participants and healthy control subjects (n = 32) during a task involving an intermixed series of unpleasant, neutral, and pleasant pictures each presented twice within their respective trial block/run. The amygdala was hand-traced on each participant's structural MRI scan and co-registered to their MRI scan. Amygdala responses were examined with a mixed-model multivariate analysis of variance.

Results: Compared with both control groups, BPD patients showed greater amygdala activation, particularly to the repeated emotional but not neutral pictures, and a prolonged return to baseline for the overall blood oxygen level-dependent response averaged across all pictures. Despite amygdala overactivation, BPD patients showed blunted self-report ratings of emotional but not neutral pictures. Fewer dissociative symptoms in both patient groups were associated with greater amygdala activation to repeated unpleasant pictures.

Conclusions: The increased amygdala response to the repeated emotional pictures observed in BPD was not observed in schizotypal patients, suggesting diagnostic specificity. This BPD-related abnormality is consistent with the well-documented clinical feature of high sensitivity to emotional stimuli with unusually strong and long-lasting reactions. The finding of a mismatch between physiological and self-report measures of emotion reactivity in BPD patients suggests they may benefit from treatments targeting emotion recognition.