Laura Fitzgerald, CNM

A flurry of concern followed last month's publication of a study which claims that the antidepressants known as SSRIs, or selective serotonin reuptake inhibitors, are only as effective as "sugar pills" in treating mild and moderate depression.  Given the staggering personal, familial, and economic toll clinical depression exacts, care providers are legitimately anxious that the more attention this study garners, the less faith patients' will place in medications that can reduce debilitating symptoms.  Nurses, clinicians, and other care providers are reminded to cast a critical eye towards any "breakthrough" research.  Providers and patients are encouraged to avoid knee-jerk responses to media hype.

It is outside of the scope of this brief article to determine the statistical validity of the study in question.  Rather, it is the author's intention to alert nurses to current debates surrounding the use of SSRIs in the treatment of mild to severe depression. 

In her article in the British Medical Journal, Susan Mayor writes that, "New generation antidepressants achieve almost no benefit compared with placebo in mild to moderate depression, with slightly more benefit in severe depression, but only because of less response to placebo." 

The meta-analysis in question was conducted primarily by Irving Kirsch, a professor of psychology at the University of Hull.  Kirsch analyzed all available data from the Food and Drug Administration's original clinical trails involving the following four medications; fluoxetine (Prozac), venlafaxine (Efexor), nefazodone (Serzone), and paroxetine (Seroxat, Paxil).  He looked at the published and unpublished results of 35 clinical trials comprising 5133 participants' data. According to the records collected by Kirsch and his team of researchers, none of these medications reached clinical significance by current standards.  Explaining the meaning of these results, Mayor notes that, "On average, the antidepressants improved the score on the Hamilton scale by 1.8 points more than placebo." 

In an online response to Mayor's article, Dr. Alastair Dobbin states that in order "to approve a drug in this class today they expect a treatment effect difference of 3 points."  In other words, by today's standards Paxil and the other listed SSRIs would not have made it to pharmacy shelves. 

Another online contributor countered that the FDA did not allow enough time to elapse between the initiation of treatment and the collection of resulting data, therefore under-appreciating the sometimes considerable delay between initiation of SSRI treatment and the production of desired antidepressant effects. 

This study does raise some important questions.  Most care providers have anecdotal evidence of patients or friends or family members who experienced dramatic improvements after treatment with one of these medications.  However, in the current context of evidenced-based medicine, these success stories may be weightless. 

Yes, Kirsh's study should feature prominently in clinical meetings and should be considered by providers when selecting treatment options for new patients.  However, it is hard to argue with the old adage to leave well enough alone in cases in which patients report improved of mild, moderate, or severe depression with SSRI treatment.

Reference:

Mayor, S. (2008). Meta-analysis shows difference between antidepressants and placebo is only significant in severe depression. BMJ, 336(466).

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