Analyzing facial expressions in depression

Depression is a mood disorder associated with impairments in the processing of social and emotional messages. This article presents a review of the literature of behavioral, clinical, pharmacological, and neuro-imaging studies dealing with a particular kind of stimuli: faces. Overall, these studies report on the existence of deficits in the processing of emotional faces in patients with major depressive disorder, especially for happiness and sadness. At the behavioral level, studies show a reduction in the recognition of positive expressions together with an enhancement in the recognition of negative emotions, in particular sadness. Attentional and memory biases have also been observed with these stimuli. At the clinical level, impairments in facial expression processing seem to improve following antidepressant treatment. However, subtle deficit may remain, which might also be present in subjects at risk for major depressive disorder. Pharmacological studies suggest that anomalies in the serotonin signalling may be involved. Finally, these deficits have been associated with structural and functional anomalies in a network of brain regions including the amygdala, prefrontal cortex (medial, orbitofrontal and anterior cingulate) and hippocampus. Studies investigating the neural dynamics of facial expression processing in depression are consistent with anomalies in the early stages of attentional orienting toward emotional stimuli in depressed patients. Recent advances in pharmacogenetics and genetic neuro-imaging relating functional and pharmacological anomalies with cognitive or emotional disorders observed in depressed patients offer new promising perspectives. © 2008 Elsevier Masson SAS. All rights reserved.