July 13, 2011

ISN'T THE LARGER POINT OF ALL THIS MEDICAL RESEARCH THAT PLACEBOS ARE EFFECTIVE?:

Are Antidepressants Just Placebos With Side Effects? (John Horgan | Jul 12, 2011, Scientific American)


Kramer's article seeks to rebut a wave of negative coverage of antidepressants, most notably a two-part essay in The New York Review of Books (which can be found here and here) by Marcia Angell, former editor of The New England Journal of Medicine and now a lecturer in social medicine at Harvard. Angell cites research suggesting that antidepressants—including both selective serotonin reuptake inhibitors (SSRIs) and other medications—may not be any more effective than placebos for treating most forms of depression.

Angell highlights a meta-analysis, carried out by the psychologist Irving Kirsch, of trials of a half dozen popular antidepressants submitted by drug companies to the U.S. Food and Drug Administration. Many of the studies were never published because they failed to yield positive results. (The practice of burying negative results from trials is still quite common, as this recent Scientific American blog post points out.) After analyzing all the FDA studies, Kirsch concluded that placebos are 82 percent as effective as antidepressants. According to Kirsch, this difference vanishes if antidepressants are compared to "active placebos," which are compounds such as atropine, an alkaloid that blocks certain nerve receptors and causes dry mouth and other symptoms, that have distinct side effects.

Angell quotes from Kirsch's new book The Emperor's New Drugs (Basic Books), in which he states that "the relatively small difference between drugs and placebos might not be a real drug effect at all. Instead, it might be an enhanced placebo effect." This "startling" claim, Angell adds, "flies in the face of widely accepted medical opinion, but Kirsch reaches it in a careful, logical way. Psychiatrists who use antidepressants—and that's most of them—and patients who take them might insist that they know from clinical experience that the drugs work. But anecdotes are known to be a treacherous way to evaluate medical treatments."

So how does Kramer begin his defense of antidepressants? With an anecdote—about a friend who benefited from antidepressants after suffering from a stroke. This rhetorical strategy should not be surprising, since Kramer's 1993 bestseller Listening to Prozac (Penguin), which contributed to the surge in popularity of Prozac and other SSRIs, relied heavily on anecdotal evidence rather than clinical data. Kramer told story after story of patients transformed by Prozac. He suggested that SSRIs might be ushering in an era of "cosmetic psychopharmacology" in which patients are not only cured of disorders but become "better than well."

The Brave New World envisioned by Kramer was always a complete fantasy. When he wrote his book in the early 1990s, studies by Eli Lilly, Prozac's manufacturer, showed that it was no more effective than older antidepressants, such as tricyclic drugs, or psychotherapy without drugs. Although Prozac was touted for its relatively mild side effects, it causes sexual dysfunction in as many as three out of four consumers. Kramer relegated a discussion of Prozac's sexual side effects to the fine print, literally, in his book's endnotes. His Times essay doesn't provide any better data for antidepressants than Listening to Prozac did. Kramer delves into an arcane discussion of how difficult it is to distinguish genuine drug benefits from placebo effects, but he does not really grapple with the claim of Angell and Kirsch that antidepressants may be active placebos.

Kramer does not mention, for example, a recent analysis of STAR*D (Sequenced Treatment Alternatives to Relieve Depression), which has been called "the largest antidepressant effectiveness trial ever conducted." According to a group of four researchers, STAR*D data show that "antidepressants are only marginally efficacious compared to placebos," and even this modest benefit might be inflated by "profound publication bias." The authors recommend "a reappraisal of the current recommended standard of care of depression."


That medical bag you got when you were a kid, with the candy pills in the thermometer, was all you ever really needed.


Posted by at July 13, 2011 6:03 AM
  

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