Researchers ran a -week double-blind, randomized, placebo-controlled trial to test whether Calmex ( ) reduces anxiety symptoms in adults diagnosed with generalized anxiety disorder. Participants were randomly assigned to Calmex or a look-alike inactive pill and attended weekly check-ins. Effectiveness was measured by the change in GAD- score. Calmex showed a greater reduction than the comparison group. What does it mean that the experiment was placebo-controlled?
