Dissociation of explicit and implicit measures of the behavioral inhibition and activation system in borderline personality disorder.

Patients with borderline personality disorder (BPD) suffer from various impairments in emotional functioning such as affective instability, inappropriate anger and unstable relationships. These deficits may influence two fundamental motivational systems, the behavioral inhibition system (BIS) and behavioral activation system (BAS). To investigate behavioral intentions and possible impairments in BPD we applied an implicit joystick task to measure implicit behavioral tendencies in response to facial expressions (happiness, sadness, anger, fear and neutral) in 25 patients with BPD and matched 25 healthy controls (HC). Additionally, we evaluated explicit approach and avoidance reactions to these social stimuli, emotion recognition abilities and subjective behavioral ratings. Our data analysis suggests that, although BPD patients accurately identified facial emotional expressions and reacted to them similarly as HC in the joystick task, they had significantly stronger avoidance tendencies in the rating task, especially for happiness and fear. On top of this they exhibited increased BIS sensitivity and decreased BAS sensitivity in the self-report measures. Possible influences are maladaptive cognitive schemas, high negative affect, insecure attachment style and a negative evaluation bias. The observed dysfunctional avoidance ratings may influence the appraisal of socially relevant stimuli and therefore adds further knowledge on social interaction problems in BPD.