A couple more thoughts on the PLoS antidepressants study

I add these observations based on quotes the Public Library of Science report on antidepressants and their alleged minimum effectiveness on milder depressions.

First, per a comment on a blog, two of the studied drugs are SNRIs, not SSRIs. The PLoS study doesn't even list SNRIs as a type of antidepressant. I quote:

Antidepressants include “tricyclics,” “monoamine oxidases,” and “selective serotonin reuptake inhibitors” (SSRIs).

Second, would you describe improvement of more than halfway from the baseline to “significant” as “marginal”? Again, I quote:

A previously published meta-analysis of the published and unpublished trials on SSRIs submitted to the FDA during licensing has indicated that these drugs have only a marginal clinical benefit. On average, the SSRIs improved the HRSD score of patients by 1.8 points more than the placebo, whereas NICE has defined a significant clinical benefit for antidepressants as a drug–placebo difference in the improvement of the HRSD score of 3 points.

(The word "marginal" is used more than once throughout the study.)

“Moderate” or even “modest” would be acceptable words. “Marginal” overstates the case.

Next, given what I’ve already said about p values, I'm not sure how much weight I would put on a total of 5,100 people in the 35 trials umbrellaed in the meta-analysis. I'm not sure how much significance I would find in one medical study that had that many people, especially if studied over a short time period.

That said, given the “lag” anti-Ds can have, the FDA is also remiss on some of their study criteria, I don’t doubt. Is two weeks too soon to allow a drug switch? In cases of severe depression, you may feel you have to try something else, which you do for the patient's sake, of course, but that should perhaps "ding" the study in some way.

That said, given that we still know little about brain chemistry, even if anti-Ds are shown to be of little effect some day, I'm not even sure that we can, today, say they are either effective or ineffective, with any degree of confidence.