Research published in August 2015 (Increasing placebo responses over time in U.S. clinical trials of neuropathic pain) and published in the Journal Pain focused on over two decades’ worth of clinical trials – 80 in all. The results showed that, as many have speculated, our placebo response is indeed getting stronger. And, because one measure of a drug’s effectiveness is its ability to perform better than the placebo, more pain-drug trials are failing than in the past. But, interestingly, the researchers found that this increase was only true for studies conducted in the U.S.