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"The data suggest that longer and larger trials are associated with bigger placebo responses,"

So, really it's not about a greater placebo effect in the US, but longer trials that change the placebo response. This isn't surprising considering how many drugs take several weeks to have any effect at all. The subject assumes that the drug is working better the longer they are on it, regardless of if its a placebo or not. This should not make it "harder for pharmaceutical companies to prove that the drug being tested is more effective than treatment with a placebo" as suggested in the summary, but the normal response to a longer trial.

The FDA's standards for response above placebo are very, very low. They are already looking into changing the rules to exclude drugs that solve the same problem that aren't just "above placebo," but "above what's available." (google "fda comparative effectiveness"). It should be harder to make new drugs that solve the same problem as existing ones: if it's not better, why should people have to pay higher prices for it (new drugs get new patents)?