Facial emotion triggered cerebral potentials in treatment-resistant depression and borderline personality disorder patients of both genders

Background: Processing facial expressions of emotion is deteriorated in depression, which might be more pronounced in treatment-resistant depression (TRD), especially when the latter is comorbid with borderline personality disorder (BPD). Neurophysiologically, both early perceptual and late cognitive cerebral processes of facial emotions can be illustrated by event-related potentials (ERPs). Methods: We therefore tried the ERPs to facial expressions of Neutral, Anger, Happiness, and Sadness in 25 patients with TRD, 15 with BPD, 22 with their comorbidity (TRD + BPD), as well as in 37 healthy volunteers. The depression levels of participants were measured with the Plutchik-van Praag Depressive Inventory (PVP). Results: There was no group difference regarding either N1 (N170), P2, N2, P3a or P3b latency or amplitude to the four facial emotions. Reaction times (RTs) to Anger (p< .01), Happiness (p< .01), and Sadness (p< .001) in TRD, and those to Anger (p< .01) and Happiness (p< .01) in TRD + BPD patients were longer than those in the healthy volunteers. RTs to the four facial expressions were positively correlated (p< .01) with their depressive moods in all participants. In addition, PVP was positively correlated with the P2 latency to Anger in TRD + BPD patients (Fz, p< .01; Cz, p< .01; Pz, p< .01). Conclusions: BPD contributed little to TRD or TRD + BPD regarding cerebral processing of facial emotions, however, other cognitive and behavioral data suggest a generalized impairment when responding to facial emotions in TRD and TRD + BPD patients, and a deteriorated perceptual processing of Anger in TRD + BPD patients.