Despite the numerous antidepressant medications available for treatment many depressed patients continue to experience symptoms of depression.

Charles B. Nemeroff, affiliated with the Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia, and associates, reviewed 34 double-blind randomized controlled trials that compared a single serotonin-norepinephrine reuptake inhibitor (SNRI), venlafaxine, to other selective serotonin reuptake inhibitors (SSRIs).

Nemeroff found that venlafaxine was superior to SSRIs in overall efficacy. Statistically, venlafaxine was superior to fluoxetine, but not to paroxetine, sertraline, or citalopram. However, venlafaxine had a higher dropout rate because of adverse reactions. Nemeroff also noted that a typical doctor would need to treat 17 patients to have a single patient benefit by being treated with venlafaxine rather than an SSRI. For example, if a doctor was treating 200 patients and switched all of them from a SSRI to venlafaxine, only 12 patients would predictably benefit by the switch in medication.