FIGURE 4.

Effect size on DSST performance of antidepressants in patients with MDD is compared with the effect size in healthy volunteers for known compounds such as acute caffeine consumption, caffeine deprivation, and diphenhydramine (an antihistamine). Benchmarking effect sizes to known compounds in clinically healthy volunteers serves as a guide to evaluating the clinical meaningfulness of particular effect sizes in cognition.^{32,39,43,44,48–53} Positive effect sizes indicate improvements in cognitive functioning, and negative effect sizes indicate decline in cognitive functioning. The top part of the graph shows the effects of antidepressant treatments on cognitive functioning, whereas the bottom part illustrates the effects of other agents known to affect cognitive functioning in healthy volunteers. Figure 4 can be viewed online in color at www.psychopharmacology.com.