Fig. 4From: The temporal trend of placebo response in migraine prevention from 1990 to 2021: a systematic literature review and meta-analysis with regressionResponder rate in the placebo arm (percent of patients with ≥ 50% reduction in MMDs, MHDs, attack frequency, migraine episodes per month, migraine days, headache attack frequency, headache days, and intensity or duration) versus year of publicationBack to article page