Inattention deficit hyperactivity disorder (ADHD), a high placebo response can minimize medication–placebo differences, compromising the development of novel medications. For a study, researchers sought to (1) assess placebo response in ADHD, (2) compare the accuracy of meta-regression and MetaForest in predicting placebo response, and (3) identify factors related to placebo response. A meta-analysis of randomized, placebo-controlled clinical trials examining pharmaceutical treatments for ADHD was carried out.