The papers today are full of the news of the meta-analysis of clinical trials of anti-depressant drugs (including Prozac) that shows such drugs only have a clinically significant effect for a very small subset of the most depressed patients. The authors also concluded that the larger effect compared to placebo for the most depressed patients was caused by those patients responding less well to placebo, not to the SSRI drugs being more effective for those patients. [I should add that if you are prescribed such drugs, you shouldn't stop taking them unless you are advised to by your GP].
Obviously, this is not good news for the companies who make these drugs. GlaxoSmithKline, who make Seroxat, said that the conclusions were at odds "with the very positive benefits seen in actual clinical practice" and that "This one study should not be used to cause unnecessary alarm". What the study is suggesting is that the benefits of the drugs seen in clinical practice may be partly related to the placebo effect, and that those benefits not related to the placebo effect are small and usually not clinically significant. That's the point that GSK need to address. But they don't, and not only that but they disingenuously describe a meta-analysis of 47 trials as 'one study'.
Eli Lilly (makers of Prozac) said that "Extensive scientific and medical experience has demonstrated that [Prozac] is an effective anti-depressant". This just ignores the evidence from the meta-analysis that says the opposite.
When I read these responses, I couldn't help but be reminded of the responses of homeopaths to the evidence from double-blinded, randomised, placebo-controlled trials that homeopathy doesn't work. They simply ignore that evidence and say that they know it works, through clinical experience or anecdotes.
It's disappointing, but perhaps not surprising, to see drug companies falling back on these unscientific statements. After all, homeopathy transparently doesn't work, but plenty of people still use it. Perhaps the companies are hoping for a similar outcome for their anti-depressants. The point here is not that these anti-depressant drugs are useless: clearly they do 'work', especially for the most depressed patients. The point is that for most people taking them, they don't work particularly well.