Ballou S, et al. - Authors attempted to investigate the factors that contributed to the high placebo response rate using data from placebo-controlled trials of patients with irritable bowel syndrome (IBS). The enrollment consisted of women with IBS with constipation who were in the placebo group of a 12-week, randomized, double-blind, phase 3 trial of the experimental medication renzapride. Findings exhibited that baseline factors linked with the placebo response in women with IBS and constipation comprised of variation in baseline pain symptoms, the severity of baseline symptoms, and early improvement of abdominal pain.