Now that over 40 million people are taking Prozac and similar medication to cheer themselves up, we learn that they may as well be taking sugar-pills. Waving the Freedom of Information act as a warrant to gain access to data drug companies haven’t wanted to publish, researchers looked again at whether people popping Prozac actually get happier than people popping placebos. Writing in the (wonderful, open-access) Public Library of Science, Irving Kirsch and colleagues found:
The response to placebo in these trials was exceptionally large, duplicating more than 80% of the improvement observed in the drug groups.
PsyBlog notes that Irving Kirsch has made a career out of studying the placebo effect, so he may be grinding his axes in this study. But overall, it looks to me like great news. It means that people who are feeling a little grotty about life can take more or less any pill and feel better. (People who are feeling very grotty about life still do better on antidepressants, the analysis found). The paper is guarded in its discussion of how decisions about drug approval and prescription are made, but they give some very interesting insights into how drug companies try to stack the jury in favour of a new drug. Here’s an example:
“Replacement of patients who investigators determined were not improving after 2 wk was allowed in three fluoxetine [Prozac] trials and in the three sertraline [Zoloft] trials for which data were reported. The trials also included a 1- to 2-wk washout period during which patients were given placebo, prior to random assignment. Those whose scores improved 20% or more were excluded from the study prior to random assignment.”
If I understand that correctly, it means that in these (mostly 6 week) trials, researchers could kick out the people who weren’t doing well right away (thus stacking the jury in favour of those who do well on Prozac), having already kicked out those who did too well before even getting the drug (this stacking the jury against those who do well on the placebo). These are the rules by which we allow the pharmaceuticial industry to operate? Honestly, it’s enough to drive you to anti-depressants.
The drugs included in the meta-analysis were: fluoxetine (Prozac), paroxetine (Seroxat), venlafaxine (Effexor) and nefazodone (Serzone)