But that doesn't mean patients should toss out that bottle of Prozac or Paxil without careful consideration, warned psychology experts and scientists responding to a study that concluded placebos are as effective as medication in all but the most depressed.
And it certainly doesn't mean that severe depression — including the mood disorders that affect nearly 21 million adults in the U.S. — should be regarded as anything but the debilitating disease that it is.
"This is about very sick people; there's something wrong with their brains," said Dr. Helen Mayberg, a professor of psychiatry neurology at the Emory University School of Medicine.
Mayberg and others worried that a study released Tuesday by Irving Kirsch of the University of Hull in England might lead depressed patients to abruptly stop their drugs without medical guidance. Kirsch and his researchers analyzed results of published and unpublished studies from the federal Food and Drug Administration to find that four of the most common new-generation antidepressants appear to help only the most severely depressed.
The drugs, which include those commonly known as Prozac, Effexor, Paxil and Serzone, worked no better than placebos in less severely depressed people, the researchers concluded.
They suggested the drugs shouldn't be prescribed unless other therapies, including counseling and lifestyle changes such as exercise, have been tried.
Don't stop abruptly
About 118 million antidepressant prescriptions are issued in the U.S. each year, but starting or stopping the drugs should be done very carefully and under medical guidance.
"If you are currently taking an antidepressant drug and it's working for you, by no means stop," Mayberg said.
Instead, patients should consider the new information and decide if it's time to evaluate their medication, added Deborah Serani, a psychologist in private practice in New York. Stopping the drugs abruptly can have dangerous results.
"It can cause a backlash of severe depressive symptoms," said Serani, who herself has taken antidepressants for 15 years, including the generic version of Prozac.
The experts said the new study provided valuable insight, but that it was based on a limited number of short-term studies in a field in which long-term results are the point. Because no one knows what causes depression, and because treatment must be individualized, each case must be evaluated on its own merits, they added.
Serani has seen severely depressed patients fail to respond to antidepressants, and she's seen mild to moderately depressed patients respond very well.
Other research has shown that patients respond better to a combination of medication and psychotherapy than to either treatment on its own, Mayberg said.
The power of the placebo effect on depression has long been recognized, said David Barlow, founder and director emeritus for the Center for Anxiety and Related Disorders at Boston University.
Antidepressants likely are overprescribed, partly because of the hurried nature of care in the U.S. health system, Barlow noted. In busy primary care practices, there's considerable pressure to do something, anything, for patients suffering from mild to severe depression.
"A placebo can make people feel better as well," he said.
Doctors must be more judicious in prescribing anti-depressants and patients must be more careful about requesting and using them, said Elinore McCance-Katz, a professor of psychiatry at the University of California at San Francisco.
That can be complicated, especially in a country where antidepressants are advertised in magazines and on television.
"What really bothers me is that big Pharma allows marketing directly to consumers," she said.
Patients generally have little opportunity to verify the drug companies' claims, she added.
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Depression must be taken seriously
The worst thing patients, their families and their doctors can do is decide that depression should not be treated seriously and carefully, Mayberg said.
"Is this can we dump on the mentally ill once again?" she said. "Their families tell them to 'snap out of it' and to 'get a grip.'"
The entire field of neuro-psychiatry needs to work harder to find the cause of the depression and to discern effective ways to treat it so that people won't be tempted by simplistic solutions.
"If that's all it took, working a little harder at the gym, we'd be done already," Mayberg said.