Friday, January 25, 2008

A warning on drug trials!

Ora sent me this article (you need to be registered to access but it's free!) from the New York Times on how drug trials are misleading:
Researchers Find a Bias Toward Upbeat Findings on Antidepressants
The makers of antidepressants like Prozac and Paxil never published the results of about a third of the drug trials that they conducted to win government approval, misleading doctors and consumers about the drugs true effectiveness, a new analysis has found. In published trials, about 60 percent of people taking the drugs report significant relief from depression, compared with roughly 40 percent of those on placebo pills. But when the less positive, unpublished trials are included, the advantage shrinks: the drugs outperform placebos, but by a modest margin, concludes the new report, which appears Thursday in The New England Journal of Medicine.
My conclusion is two-fold. First, I am convinced that virtually all studies suffer from this publication bias effect (i.e. null or negative trials are conveniently not published or non-publishable) including stuttering research (not just on medication though). Second, I am always amazed at how strong the placebo effect is, and one can certainly argue that even the placebo is a significant improvement which the patient wouldn't have gotten if s/he hadn't taken the worthless or minimal-effect medication!!! Strange world...

1 comment:

Ora said...

It’s interesting to speculate whether there’s a similar bias in our own field of interest, stuttering research – with regard to either drug therapies or other interventions, such as speech therapy.

It’s easy to find some plausible factors underlying this effect with respect to drug tests, which are typically funded by the drug companies. Some of the factors that motivate this effect are clear – particularly: negative effect on the marketing of the drug, and lack of professional recognition for finding negative results.

For non-medical interventions (typically falling collectively within the category of speech therapy), the first factor (big money) is no longer present to such an extent, though not absent entirely. But the professional recognition factor clearly remains. If a stuttering researcher's statistician discovers that kids who have bacon and eggs for breakfast improve their speech at a faster rate than the group he's treating with his own favorite style of therapy, do you think he'll be rushing to report that?

Stuttering researchers are not philanthropists. They have interests other than Truth alone. Their decisions to publish or not are based on their own self-interests, which do not always favor full disclosure. Your anecdotal report from your January 23 blog entry asks “Have you ever heard a therapist at a conference talking about their mistakes?” which is surely, in a small sense, an example of this sort of bias.