While it is true that in the particular case you mention the effect could be a correlation, and not a cause, I think the weight of evidence (along with common sense) points to advertising and promotion having a significant effect on both doctors and patients.

In 2000 $2.46 billion was spent by drug companies on DTC (direct-to-consumer) advertising, up from $791 million in 1996. During that time requests from patients for drugs they felt they need also began to rise, with one out of four patients making such requests. A survey conducted by the FDA found that 85% of physicians reported that their patients asked either “often” or “all the time” for advertised drugs.

I think it would be difficult to argue that this is correlation, i.e. that the patient’s request for the drugs are driving the advertising increases. The patients wouldn’t even know about the drugs if it wasn’t for advertising.

Doctors are also clearly influenced by pharmaceutical advertising and promotion. As Dr. Jerry Avorn from Harvard said in his study:

“Pharmaceutical marketing is about the most important source of knowledge about new drugs for most physicians, and a major form of continuing conditioning as well.”

If the only way most doctors are learning about these drugs is by reading promotional literature, as Avorn’s study suggests, then by definition they are being influenced by promotion. And while this does not prove that drug promotion is responsible for the rise in prescriptions beyond a shadow of a doubt, I think it’s a perfectly robust and supportable hypothesis.

As to your second point, I was referring to the combination of unpublished and published studies. Kirsch and colleagues used the Freedom of Information Act to obtain access to the FDA database, which includes all published and unpublished studies. Using that database for their meta-analyses, they determined that antidepressants have no clinically meaningful advantage over placebo.

For more detail on this, see my original post Placebos as effective as antidepressants”, and today’s post A closer look at antidepressants. Make sure to check out the comments on that post for further discussion.

“Does all of this advertising and promotion actually influence doctors? You bet it does. A government report found that in just one year the most heavily advertised drugs had prescription increases of 25% (U.S. General Accounting Office, 2002). There is even a formula that generally applies to drug advertising: each dollar spent on advertising increases sales by $4.”

Correlation vs Causation… this effect could simply be driven by pharmaceutical companies advertising their most effective, and thus most prescribed, medications. In this case it would not support the conclusion that the advertising is influencing doctors. (This possibility is not mutually exclusive with yours, and I don’t think the reality is 100% one or the other.)

“When these independent and unpublished studies are analyzed, a very different picture of depression and the efficacy of antidepressants begins to emerge.”

I can’t tell if you mean when *only* the unpublished studies are analyzed, or when they are included with published studies. If the former is the case, then you’re subjecting yourself to the same sampling bias that you accuse the drug companies of (but, of course, pointing you toward the opposite conclusion).

I’m grateful for your participation and support!

I was aware of the antidepressant effect of D, but not of Dr. McCleary’s work. Thanks for pointing that out. I’ll read his articles on D’s role in the brain, and yes, I do intend to write more on the relationship between the fat soluble vitamins in the future.

It may be a while, though. I have several more articles in the antidepressant series to write first!

Best,
Chris

Did you know that Vitamin D is an antidepressant? It ameliorates SAD (seasonal affective disorder) very well.

I’m looking forward to your review on the relationship betw A/D/E/K2! You write so wonderfully! Keep up the strong work

-G

I fully agree with you about the “chemical imbalance” thing; it’s incredibly dense. They try to spin it like you were born with depression and there’s nothing you can do about it but take a drug. I have a friend who’s into mood disorder research and I’ve talked to him about that meta-analysis showing no significant effect of ADs.

First of all, he has no dog in the fight because his interest in mood disorders is purely academic. I can vouch for his lack of bias toward antidepressants. Here’s what he told me. Basically, what we call “depression” is actually a collection of related disorders. Antidepressants only work on a subset of them.

There are “responders” and “non-responders” in any group of people who receive antidepressants. For responders, antidepressants can be very effective. When you do a meta-analysis where you’re averaging everyone with “depression” together, the effect of an antidepressant will be small or nonexistent because of the heterogeneity. So this is a problem with saying that antidepressants aren’t effective based on that analysis.

I don’t have a problem believing that antidepressants work for some people. They certainly work in animal models of depression, where there is no placebo effect. I don’t think we should banish them from planet Earth. But I do think the fact that we use them so much points to a bigger problem that we should be addressing by other means.