Full Program »
Habituation of Amygdala Response to Unpleasant Pictures in Borderline Personality Disorder Patients with and without a History of Suicidal Behavior
Background: Patients with borderline personality disorder (BPD) are often characterized by emotion dysregulation and recurrent suicidal behavior. The rate of suicide in BPD is 8-10%, 50 times that of the general population. One form of emotion dysregulation is the inability to habituate to repeated unpleasant emotional stimuli. The amygdala is central to the processing of emotional information and abnormalities in this brain region have been linked to affective impairments in BPD. Our prior work showed that BPD participants exhibited prolonged fMRI BOLD responses in the amygdala to emotional stimuli, indicating longer time to return to baseline, and a failure to down-regulate (habituate) amygdala response with repeated presentations of emotional pictures, suggesting a deficit in regulating emotional arousal (Hazlett et al 2012; Biol Psychiatry). Despite progress in understanding risk factors of suicidal behavior, little is known about the role of emotion dysregulation and its underlying neural circuitry which may confer suicide risk.
Methods: The current study employed fMRI to examine amygdala activation in three demographically-matched groups recruited from the community using newspaper and online advertisements: BPD patients with a history of suicidal behavior (n=15), BPD patients with no history of suicidal behaviors (n=18), and healthy controls (n=32) during a task involving an intermixed series of novel and repeated unpleasant (U), neutral (N), and pleasant (P) pictures. All participants were rigorously screened and received structured diagnostic interviews (SCID and SIDP). Healthy controls had no Axis I or personality disorder. All BPD participants met DSM-IV criteria for BPD and were unmedicated at the time of their fMRI scans. The amygdala volume was hand-traced on each participant’s structural MRI scan blind to diagnosis and co-registered to their fMRI scan.
Results: Amygdala BOLD activation was examined with a mixed-model multivariate analysis of variance (Group [Healthy controls vs. BPD/no suicidal behavior vs. BPD/suicidal behavior] x Picture type [unpleasant, neutral, pleasant] x Time [novel, repeated] x Hemisphere (L, R). Those with BPD and a history of suicidal behavior showed an increased amygdala response to repeated unpleasant pictures compared to those with BPD and no history of suicidal behavior and healthy controls. The groups did not differ on BOLD activation to neutral or pleasant images (Group x Picture type x Time interaction, p<0.001, Wilks). Among the BPD patients, greater amygdala activation in response to repeated unpleasant pictures was also associated with greater severity of suicidal behavior (p<0.01).
Conclusions: These novel findings indicate that emotion processing and specifically, dysregulation is impaired commensurate with severity of suicidal behavior in BPD and suggest that amygdala activity may be a promising biomarker of suicide risk.