The Problem with Prozac
By Martin
Enserink
Antidepressants
of the “Prozac generation” have been hailed as miracle drugs and they're a
multibillion-dollar boon to the pharmaceutical industry. But a controversial
new study claims that the drugs, which largely replaced older medicines in the
1990s, do little good for the vast majority of patients who take them. Only in
the most severely depressed people do these so-called selective serotonin
reuptake inhibitors (SSRIs) really outperform
placeboes, according to the paper, which analyzed both published and
unpublished studies.
Many
published papers have demonstrated that SSRI's help
relieve depression. But clinical trials in which drugs fail sometimes don't
appear in journals, a phenomenon called publication bias. These negative trials
do get sent to the U.S. Food and Drug Administration (FDA), however, and the
agency looks at all trials performed on a drug before approving it.
Psychologist Irving Kirsch of the University of Hull,
U.K., relied on FDA's requirement to better assess true benefits of antidepressants.
Using the
Freedom of Information Act, Kirsch obtained from FDA the trial results for all SSRIs approved between 1987 and 1999. In a much-debated
paper published in 2002, Kirsch showed that the drugs lowered patients' scores
on the widely-used 52-point Hamilton Rating Scale of Depression only 1.8 points
more than did placeboes--a difference that's statistically significant yet
almost meaningless.
But after
the 2002 report, critics charged that Kirsch's overall finding might mask
improvements caused by the drugs in certain subgroups of patients. So Kirsch
and colleagues at four institutes in the
Compared
to placeboes, the SSRIs showed no benefit in
moderately depressed patients. Only those starting with the very highest
depression rating--corresponding to s severely debilitating disease--reaped a
clinically significant benefit. Because SSRIs, like
all drugs, come with risks, most patients should try other treatments, such
cognitive therapy, first, says Kirsch.
But
others are not convinced that an entire generation of depression drugs does so
little. In the studies Kirsch analyzed, a very high proportion of patients responded
to placebos, says psychiatrist Peter Kramer of Brown Medical School in
Providence, Rhode Island, author of the bestseller Listening to Prozac.
That may have been because researchers, eager to enroll as many patients as
they could, included many who were not that ill at all, he says. That bias
could mask a strong SSRI response among those who took the drugs.
The
design of clinical trials are designed before a depression drug is approved
also tends to boost placebo rates, says David Nutt, head of the
Psychopharmacology Unit at the
Kirsch
says he's not surprised that doctors and patients have a more favorable
impression of SSRIs than he believes they deserve.
Many depressed patients improve no matter what, he says, and it's easy to
attribute improvement to a drug.
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