Antidepressant use nearly tripled between 1988 to 1994 and 1999 to 2000, according to the CDC. The large majority of these are SSRIs, but recent studies suggest they are not anymore effective than placebo (dummy) treatment.
Drug vs. placebo
A meta-analysis conducted by the University of Hull found there to be no significant benefit of antidepressants (specifically SSRIs) over placebo, or sugar pill, in moderately depressed patients.
The researchers reviewed all clinical trials of SSRI treatment submitted to the FDA, specifically looking at patient improvement on the Hamilton Rating Scale for Depression (HRSD). The HSRD is a commonly used diagnostic tool for rating severity of depression and involves 17 to 21 questions with a range of possible scores. The most common scoring of the HSRD suggests that scores between 0 and 6 indicate a normal person relative to depression, scores between 7 and 17 indicate mild depression, scores between 18 and 24 indicate moderate depression, and scores over 24 indicate severe depression.
The meta-analysis found that the drug benefit over placebo only reached clinical significance in patients with an initial HSRD score of 28 or higher–a severely depressed population. Moreover, the apparent effect of antidepressants in severely depressed patients was not only small, but it reflected a decrease in responsiveness to placebo rather than an increased response to the antidepressant. In other words, the antidepressant only makes a small difference in the most severely depressed populations, yet the placebo effect is large in treating mild to moderate depression.
A previous meta-analysis of clinical trials submitted to the FDA found that, on average, antidepressants improved patients’ HSRD scores by only 1.8 points, a marginal and in some cases, clinically insignificant improvement. The UK National Institute for Health and Clinical Excellence (NICE) defined clinical significance of drug over placebo as an improvement in HSRD score of 3 points or higher, a standard that most antidepressants fail to meet. Furthermore, about 80 percent of the antidepressant effect was duplicated in placebo treatment.
The STAR*D report
Every year, 9.5 percent of the U.S. population, or roughly 20.9 million people, are affected by depression. Many of these people will try antidepressants, and for those people with treatment-resistant depression, they will likely try multiple antidepressants in search of one that works for that person. The STAR*D study, or Sequenced Treatment Alternatives to Relieve Depression, funded by the NIMH, investigated this method of switching antidepressants in hopes of alleviating depressive symptoms.
The results suggest that patients (with treatment-resistant depression) are more likely to beat depression after trying several treatment strategies. However, those patients who only improved their symptoms, rather than eliminating them, were less likely to remain well, and those who had to try several medications were even more likely to experience a relapse. The study underscores the powerful nature of severe Major Depressive Disorder (MDD) and the need to better understand the underlying mechanisms causing depression so we can find more effective treatment strategies.
Related material: Types of antidepressants
