BMJ Evidence-based Medicine, 30(5), 295-304
To investigate the efficacy and safety of open-label placebos (OLP) in premenstrual syndrome (PMS).
Randomised controlled trial.
Switzerland, 2018-2020.
150 women (18-45 years of age) with PMS or premenstrual dysphoric disorder.
Random assignment (1:1:1) to treatment as usual (TAU), OLP without treatment rationale (OLP-), or OLP with treatment rationale (OLP+). OLP consisted of two placebo pills per day for 6 weeks.
Primary outcomes were PMS symptom intensity and interference between groups across three menstrual cycles (MC1-MC3); adverse events (ie, safety) were measured at weeks 3 and 6 after the start of the intervention. Secondary outcomes were psychological and somatic subscales of PMS symptom intensity, and adherence.
From 2 August 2018 to 3 December 2020,
Frey Nascimento, A., Gaab, J., Degen, B., Rytz M, Holder, A., Sezer, D., Buergler, S., Meyer, A. H., Kirsch, I., Kossowsky, J., & Locher, C. (2025). Efficacy of open-label placebos for premenstrual syndrome: a randomised controlled trial. *BMJ evidence-based medicine*, *30*(5), 295-304. https://doi.org/10.1136/bmjebm-2024-112875
Frey Nascimento A, Gaab J, Degen B, Rytz M, Holder A, Sezer D, et al. Efficacy of open-label placebos for premenstrual syndrome: a randomised controlled trial. BMJ Evid Based Med. 2025;30(5):295-304. doi:10.1136/bmjebm-2024-112875
Frey Nascimento, Antje, et al. "Efficacy of open-label placebos for premenstrual syndrome: a randomised controlled trial." *BMJ evidence-based medicine*, vol. 30, no. 5, 2025, pp. 295-304.