Treating Depression: Is there a placebo effect?

A Harvard scientist says the drugs used to treat depression are effective, but for many, it's not the active ingredient that's making people feel better. It's the placebo effect.

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Kirsch: --work. And, for the patients and the psychiatrists, it's clear why they would say the drug works. They take the drug; they get better. Our data show that as well.

Stahl: You're just saying why they get better.

Kirsch: That's right. And the reason they get better is not because of the chemicals in the drug. The difference between drug and placebo is very, very small; and in half the studies non-existent.

Kirsch and his studies have triggered a furious counterattack - mainly from psychiatrists, who are lining up to defend the use of antidepressants like Dr. Michael Thase, a professor of psychiatry at the University of Pennsylvania School of Medicine, who has been a consultant to many of the drug companies.

Stahl: Irving Kirsch says that depressants are no better than placebo for the vast majority of people with depression, the vast majority. Do you agree with that?

Michael Thase: No, no. I don't agree. I think you're confusing, or he's confusing, the results of studies versus what goes on in practice.

He says that Kirsch's statistical analysis overlooks the benefits to individual patients.

[Thase with patient: Have a seat.]

And while he agrees there's a substantial placebo effect -

[Thase: Have you been keeping track of your depression scores?]

Especially for the mildly depressed, using a different methodology, he finds that the drugs help 14 percent of those moderately depressed, and even more for those severely depressed.

Thase: Our own work indicates pretty convincingly that this is a large and meaningful effect for a subset of the patients in these studies.

Stahl: But even by your own numbers more people, maybe twice as many people, are having a placebo effect than are actually being helped by the drug.

Thase: That's correct.

Stahl: In the moderate range?

Thase: That's correct.

Stahl: And this isn't troubling to you?

Thase: I wish our antidepressants were stronger. I hope we have better ones in the future. But that 14 percent advantage over and above the placebo is for a condition that afflicts millions of people, that represents hundreds of thousands of people who are better parents, who are better workers, who are happier and who are less likely to take their life.

Since the introduction of Prozac in the 1980s, prescriptions for these drugs have soared 400 percent -

[Commercial: I used to be happy, I remember being happy...]

-- with the drug companies having spent billions over the years advertising them.

Stahl: I don't know about you, but I'm seeing more women running through daisy fields after looking morose than ever before.

Dr. Walter Brown: Absolutely. There's a lot of hype out there.