Acute administration of antidepressant medication increases emotional information processing for positive information in both depressed and healthy persons. This effect is likely relevant to the therapeutic actions of these medications, but it has not been studied in patients with major depressive disorder taking antidepressants as typically prescribed in the community.
The authors used eye tracking to examine the effects of antidepressant medication on selective attention for emotional stimuli in a sample of 47 patients with major depressive disorder (21 medicated and 26 unmedicated) and 47 matched comparison subjects without depression. Participants completed a passive-viewing eye-tracking task assessing selective attention for positive, dysphoric, threatening, and neutral stimuli in addition to providing medication information and self-report measures of depression and anxiety severity.
Depressed participants currently taking antidepressants and nondepressed comparison subjects demonstrated greater total gaze duration and more fixations for positive stimuli compared with unmedicated depressed participants. Depressed participants on medication also had fewer fixations for dysphoric stimuli compared with depressed participants not on medication.
Antidepressants, as prescribed in the community to patients with depression, appear to modify emotional information processing in the absence of differences in depression severity. These results are consistent with previous work and indicate a robust effect for antidepressants on positive information processing. They also provide further evidence for modification of information processing as a potential mechanism of action for antidepressant medication.