Sugar pills, antidepressants, and the miracle of the human brain

[drwex]

Chasing other links I stumbled across this:

As a proportion of the drug response, the placebo response was constant across different types of [antidepressant] medication (75%), and the correlation between placebo effect and drug effect was .90. [...] These data raise the possibility that the apparent drug effect (25% of the drug response) is actually an active placebo effect.

In English: it's possible that all reported effects of antidepressant medication are placebo effects. It's quite likely that 75% of reported effects are placebo.

More recently, these authors replicated the work using studies from the FDA database. FDA studies are done as part of drug approval processes. They're generally not published in refereed literature and there have been accusations that they're slanted in favor of the drugs. That is, the studies are done in order to speed drugs through the approval process and may overreport positive effects and underreport negatives. So in theory you'd see a larger effect for ADs if you analyzed these studies. In fact:

Kirsch et al. reported an 18% difference between drug and placebo.

The debate is actually fairly nuanced. There's been some good work recently looking (via MRI) at the neurochemical mechanisms triggered by placebos. There is some evidence that the difference between AD and placebo increases with the severity of depression, though that might be due to differences between active and inert placebos - people with serious depression are often familiar with the side effects of ADs and can recognize when given a sugar pill that doesn't have the expected side effects.

Nobody's claiming that ADs don't work. The claim is that they do work... and sugar pills work, too.

Title: "Listening to Prozac but hearing placebo: A meta-analysis of antidepressant medication."
Authors: Kirsch, Irving; Sapirstein, Guy
Publication: Prevention & Treatment. 1(1), Jun 1998
<http://content.apa.org/journals/pre/1/1/2>

Title: "The emperor's new drugs: An analysis of antidepressant medication data submitted
 to the U.S. Food and Drug Administration."
Authors: Kirsch, I., Moore, T. J., Scoboria, A., & Nicholls, S. S.
Publication: Prevention & Treatment, 5, art. 23
<http://journals.apa.org/prevention/volume5/pre0050023a.html>

Comments

[drwex]

my personal experience with psychotropic medications indicates that there *is* in fact a difference in the effects of different medications.

I'm not trying to debate your (or anyone else's) personal experience. What this research is saying is that it's quite likely that you could have gotten the same effect without taking the particular pill involved.

CBT+drugs has been shown to be more effective than either alone. What has NOT been shown is how CBT+placebo compares, and that's the point here.

I'm not going to shed any tears for big pharma. If people decide they can get by without drugs and do so, then more power to 'em.

the proper balance of medications--a balance which sometimes needs to be fine-tuned on a regular basis--can make a marked difference in the life of someone with persistent, chronic mental illness.

Yes, and so can placebos. As I said in the posting, nobody's arguing that ADs don't work. What's at issue is the method by which they work. If their primary path of operation is placebo effect (which it sure looks like) then we're doing people a disservice by giving them chemicals that have serious side effects when other methods might be as effective but do less collateral damage.

[darkrosetiger.livejournal.com]

CBT+drugs has been shown to be more effective than either alone. What has NOT been shown is how CBT+placebo compares, and that's the point here.

I somehow missed the definition of CBT in the above post. I was kind of confused.

[drwex]

Hee. I love that the abbreviation causes that. Of course, some people think I'm talking about Computer-Based Training. Though in this case, the reference is to Cognitive-Behavioral Therapy (aka "talk" therapy).

[keyne.livejournal.com]

What this research is saying is that it's quite likely that you could have gotten the same effect without taking the particular pill involved.

I'm a big believer in the power of the human mind, but it's a little difficult for me to believe that so many folks taking Effexor are inventing "brain shivers" independently. Or that anybody taking placebos would want to. :/

[drwex]

No one is claiming anything is "invented." The claim is that the effect on depression in patients with mild to moderate symptoms is almost entirely placebo effect.

The point of differentiating active vs passive placebos is to produce more accurate simulations of the effects of ADs. I can't say whether Effexor was particularly studied or not.