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Prozac vs. Placebos
BY DAVID NOONAN AND GEOFFREY COWLEY
NEWSWEEK, July 15, 2002, Pages 48-49
A new study concludes that America's favorite antidepressants
are little better than sugar pills. Have the drugs been over
hyped? It's not that simple.
Over the past 14 years, millions of Americans have escaped
the debilitating and sometimes lethal grip of depression with
the help of a handful of popular drugs, including Prozac,
Zoloft and Paxil. This new generation of antidepressants,
decidedly safer and easier to use than the medications they
replaced, offered welcome relief to a wide variety of patients
and racked up billions in sales. As the pills changed lives
and even saved them, they became part of the cultural landscape,
inspiring countless articles, books and talk-show segments.
Today more than 7 million Americans take these drugs for depression,
and the number is still climbing. All of which leaves Irving
Kirsch unimpressed. Indeed, according to Kirsch, the author
of a forthcoming study of antidepressants titled "The Emperor's
New Drugs", America's favorite pills "may have no meaningful
pharmacological effect at all."
Anti-drug zealots have said that for years, but Kirsch is
a scientist, and he has data to back his assertion. Prozac
and its cousins -- the so-called SSRIs -- are all thought
to work by boosting the effects of the neurotransmitter serotonin
(and in some cases norepinephrine). Is it possible that all
this chemical manipulation is unnecessary -- that people feel
better on these drugs simply because they think will? In hopes
of finding out, Kirsch, a psychologist at University of Connecticut,
pooled data from 38 studies on six drugs approved by the Food
and i Drug Administration between 1987 and 1999 (the three
above, and Serzone, Celexa and Effexor). The studies were
placebo-controlled clinical trials in which some patients
were given actual drugs while others got pills with no active
ingredients. The studies didn't show any lack of effect. In
fact, the patients improved markedly. The problem is that
people who got placebos fared almost as well as those getting
real drugs. On average, people on placebos enjoyed eight-point
improvement on the 50-point Hamilton Depression Scale, while
those on medication managed a 10-point improvement. It's no
secret placebos can ease depression in short-term studies,
but Kirsch and his colleagues raise an unsettling possibility.
In a paper appearing next week in Prevention & Treatment,
an online journal published by the American Psychological
Association (apa.org), they argue that the SSRIs' active ingredients
may account only for the two-point difference between drug
and placebo, not the whole 10-point benefit that users enjoy.
If so, says Kirsch, the benefits are "clinically negligible."
There are a couple of problems, though. First, drug effects
and placebo effects may not be "additive." In other words,
even if it's possible to reproduce 80 percent of a drug's
effect with a placebo, that doesn't mean the people taking
the drug derive 80 percent of their benefit from the placebo
response. If people received the drug without their knowledge,
would they get only 20 percent of the effect? The question
is worth asking, but it's difficult to answer, because researchers
can't study drugs by slipping them into people's coffee. Drug
trials require informed consent -- and once participants know
what's going on in a study, expectations rise. But suppose
80 percent of the antidepressant effect is just placebo. Is
there a practical way to tap that benefit in the absence of
an actual drug? If clinicians stopped prescribing antidepressants,
patients wouldn't lose only the two-point advantage that treatment
offers over placebo, they would lose the whole l0-point improvement.
And no one is suggesting that drugmakers start bottling sugar
pills.
The new study might well prompt some depressed people to
skip the drugs altogether. If the benefits are negligible,
why endure side effects that can include nausea, nervousness,
sweating, tremors and decreased libido? But while Kirsch thinks
psychotherapy -- the good old talking cure -- is an effective
alternative, he does not advise anyone to stop using antidepressants.
Neither does Dr. Rodrigo Muñoz, past president of the American
Psychiatric Association. Like many clinicians, he believes
the drugs have a much greater effect than Kirsch's analysis
suggests. "Even if 20 percent is the best we have,"' he says,
"I'll live with it until we have something better." Muñoz
notes that 15 percent of people with depression end up killing
themselves. "When I see a patient who is suicidal, I use all
the artillery. I am not going to say, 'Well, 20 percent is
not enough for me.'"
A large part of the problem in assessing the effectiveness
of the antidepressants is the maddening complexity of depression
itself, with its wide range of symptoms and many levels of
disability. Dr. Walter Brown of Brown University Medical School
says the antidepressants "are probably not as effective as
the hype around them would suggest." But Brown, who wrote
a commentary on Kirsch's study that will also be published
in Prevention & Treatment, believes the drugs are more
powerful than Kirsch concludes. He says the mild and moderately
afflicted patients who typically participate in clinical trials
can exaggerate the placebo response. In Brown's experience,
severely depressed patients do not respond nearly as well
when treated with placebos. He believes the drugs are more
effective in the real world, when they are used to treat a
range of sick people over long periods.
Some who question the efficacy of antidepressants say the
massive promotional efforts by the drugmakers may actually
boost the placebo response. "One day we may look back and
marvel at the stroke of marketing genius that led to calling
these medications antidepressants in the first place," says
clinical psychologist David Antonuccio of the University of
Nevada School of Medicine. But Dr. Michael Miller of Harvard
Medical School says that in his clinical experience, the placebo
response is limited. Most of his patients enjoy a brief improvement
no matter what treatment they receive. Those getting only
a placebo response soon return to their misery, he says. But
those responding to medication enjoy longer-term benefits.
Even Kirsch admits that the real problem may be figuring
out the best way to measure the power of the drugs. For the
millions who owe their peace of mind to the antidepressants
they take, the point may be irrelevant. In the end, anything
that lightens the days of those who suffer depression is a
good thing.
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