The temporal electrocortical profile of emotive facial processing in depressed males and females and healthy controls.

BACKGROUND: Previous work indicates that emotive processing, such as of facial expressions, may be altered in major depressive disorder (MDD). Individuals with MDD tend to exhibit a mood-congruent processing bias, though MDD may also be characterized by blunted emotive processing in general. Females tend to exhibit enhanced facial emotive processing than males. Few groups have examined the temporal electrophysiological event-related potential (ERP)-indexed profiles, spanning preconscious to sustained, conscious processing of facial expressions in MDD; systematic comparisons of ERPs to emotive stimuli between depressed males and females are also lacking.
METHODS: This study examined the temporal ERP profile to a simple expression recognition task in depressed adult males and females (N=52; 29 females) and controls (N=43; 23 females).
RESULTS: The MDD group rated facial expressions as sadder overall than controls. Females exhibited enhanced and speeded pre- and conscious face processing than males. Subtle group differences emerged to specific expressions at mid-latency ERPs (N2, P2) indicating both blunted late pre-conscious perceptual processing of expressions and prolonged processing of intensely sad faces. LIMITATIONS: A more involved emotive processing task, employing threatening faces, may have revealed more robust group ERP differences. Menstrual cycle should also be controlled for in future work.
CONCLUSIONS: This is the first study to systematically assess the temporal ERP profile, including of ERPs preceding the face-sensitive N170/VPP, to expressions in MDD. Overall, early perceptual and late conscious expression processing did not differ fundamentally between groups. Altered emotive processing may be a candidate index for monitoring and predicting antidepressant treatment outcome.