New Report Finds No Significant Differences in Effectiveness of Antidepressants

RESEARCH TRIANGLE PARK, N.C. — Researchers found no significant differences in the effectiveness of popular antidepressants, according to a new report by the RTI International-University of North Carolina at Chapel Hill Evidence-based Practice Center and Danube University, Austria.

The report, funded by the Agency for Healthcare Research and Quality and published in the Annals of Internal Medicine, found that second-generation antidepressants, the mostly commonly prescribed depression medications, were similar in  effectiveness for the treatment of major depressive disorder, but exhibited some differences among their side effects.

The report is based on a systematic review of 234 studies that assessed 13 commonly prescribed second-generation antidepressants: bupropion, citalopram, desvenlafaxine, duloxetine, escitalopram, fluoxetine, fluvoxamine, mirtazapine, nefazodone, paroxetine, sertraline, trazodone, and venlafaxine -- and their specific trade names. The studies included randomized controlled trials with active or placebo controls, observational studies and systematic reviews.

The report could not confirm the 2009 controversial findings of an Italian-British research team that claimed that two antidepressants were superior to the others.

The research team assessed evidence on comparative benefits and harms of second-generation antidepressants, including variations of effects in patients with accompanying symptoms and patient subgroups.

“The pharmaceutical industry spends an estimated $400 million per year to market antidepressants. Our research shows that scientific evidence  does not warrant recommending a particular antidepressant on the basis of greater effectiveness,” said Gerald Gartlehner, MD, MPH, a senior health research analyst at RTI and the report’s lead author. “Nevertheless, antidepressants cannot be considered identical drugs. Differences in onset of action and adverse events may influence the choice of a medication for a specific patient.”

For example, mirtazapine has a faster onset of action than citalopram, fluoxetine, paroxetine, and sertraline, and bupropion has fewer sexual side effects than escitalopram, fluoxetine, paroxetine, and sertraline.

The researchers also found no differences in patients based on age, sex, ethnicity, or comorbidities, although evidence within subgroups was limited.

The evidence review was conducted by RTI-UNC Evidence-based Practice Center, a collaboration between RTI and the five health professions schools and the Cecil G. Sheps Center for Health Services Research at the University of North Carolina at Chapel Hill. The project was supported by the Agency for Healthcare Research and Quality (AHRQ).