Increased amygdala response to positive social feedback in young people with major depressive disorder.

BACKGROUND: Studies of depressed patients have demonstrated increased amygdala activation to negative affective stimuli. In this study, we used a paradigm that employed personally relevant social stimuli, which are known to strongly activate the amygdala, to test whether the amygdala demonstrated aberrant activity in depressed participants as they responded to stimuli with positive valence.
METHODS: Nineteen patients with major depressive disorder, aged 15 to 24 years, were matched with 20 healthy control participants. They completed a novel functional magnetic resonance imaging task in which they received social feedback from people who they believed had evaluated them. Voxelwise statistical parametric maps of brain response to positive social feedback and to a control feedback condition were compared to test the hypothesis that differences in neural response between depressed and control participants would arise in the amygdala.
RESULTS: Depressed participants showed increased neural response to the positive- versus control-feedback condition in the amygdala (p < .05, corrected). An exploratory analysis showed that depressed participants responded to faces from both feedback conditions with increased activity in regions subserving social appraisal (ventrolateral prefrontal cortex and inferior parietal cortex) and affective processing (pregenual anterior cingulate cortex and anterior insular cortex; p < .001, uncorrected).
CONCLUSIONS: Depressed patients responded to positive social feedback with increased amygdala activation, demonstrating that amygdala hyperresponsivity in depression is not restricted to negatively-valenced stimuli. The heightened sensitivity of depressed participants to social evaluation may help explain symptoms of depression such as social withdrawal.