Background: Many studies have explored associations between depression and facial emotion recognition (ER). However, these studies have used various paradigms and multiple stimulus sets, rendering comparisons difficult. Few studies have attempted to determine the magnitude of any effect and whether studies are properly powered to detect it. We conducted a meta-analysis to synthesize the findings across studies on ER in depressed individuals compared to controls.
Method: Studies of ER that included depressed and control samples and published before June 2013 were identified in PubMed and Web of Science. Studies using schematic faces, neuroimaging studies and drug treatment studies were excluded.
Results: Meta-analysis of k = 22 independent samples indicated impaired recognition of emotion [k = 22, g = -0.16, 95% confidence interval (CI) -0.25 to -0.07, p < 0.001]. Critically, this was observed for anger, disgust, fear, happiness and surprise (k's = 7-22, g's = -0.42 to -0.17, p's < 0.08), but not sadness (k = 21, g = -0.09, 95% CI -0.23 to +0.06, p = 0.23). Study-level characteristics did not appear to be associated with the observed effect. Power analysis indicated that a sample of approximately 615 cases and 615 controls would be required to detect this association with 80% power at an alpha level of 0.05.
Conclusions: These findings suggest that the ER impairment reported in the depression literature exists across all basic emotions except sadness. The effect size, however, is small, and previous studies have been underpowered.