Researchers have been questioning the degree to which SSRIs affect MDD. The evidence from meta-analyses of placebo-controlled trials implies that the pharmacological effects of SSRIs may be small and that up to 75% of symptom relief may be attributable to nonspecific placebo effects and spontaneous remission.1,2
However, researchers from Northwestern University Feinberg School of Medicine, the University of Pennsylvania, Vanderbilt University, and the University of Alabama at Birmingham are challenging these data. They point out that efficacy data are based on total symptom scores and contend that antidepressant medications may simply influence some symptoms and not others.3
Their research—an 8-week double-blind, placebo-controlled trial of paroxetine—shows that SSRIs may affect the psychological but not the somatic symptoms of depression and anxiety.
The trial included 180 outpatients with moderate to severe MDD. One hundred twenty were randomly assigned to paroxetine and the remainder to placebo. Symptom measures administered before the trial and at week 8 included the 17-item Hamilton Rating Scale for Depression (HRSD), which was modified to include atypical symptoms; the 14-item Hamilton Rating Scale for Anxiety (HRSA); and the 21-item Beck Anxiety Inventory (BAI).