Differential effects of serotonergic and noradrenergic antidepressants on brain activity during a cognitive control task and neurofunctional prediction of treatment outcome in patients with depression

Background: we investigated the differential effects of serotonergic and noradrenergic antidepressants on brain activation in patients with major depressive disorder during a stroop task. we predicted that pretreatment hyperactivity in the rostral anterior cingulate cortex would predict better treatment outcomes. methods: in total,20 patients underwent naturalistic open-label clinical treatment with citalopram (n = 12) or reboxetine (n = 8). we performed functional magnetic resonance imaging at baseline and after 6 weeks of treatment. results: there were no significant group differences in clinical characteristics,treatment outcomes or baseline fmri activations. the group by time interaction revealed significant voxels in the right amygdala-hippocampus complex (p < 0.05,family-wise error corrected by use of the bilateral amygdala and hippocampus mask image as a small volume),indicating a posttreatment blood oxygen level- dependent signal decrease in the citalopram group. pretreatment hyperactivity in the rostral anterior cingulate cortex was not related to symptom improvement. limitations: our study was a nonrandomized clinical trial. conclusion: these results indicate that serotonergic and noradrenergic antidepressants have a differential effect on brain activity,especially in the amygdala and hippocampus. © 2010 canadian medical association.