{
  "abstract": "Objective To investigate the efficacy and safety of open-label placebos (OLP) in premenstrual syndrome (PMS).Design Randomised controlled trial.Setting Switzerland, 2018–2020.Participants 150 women (18–45 years of age) with PMS or premenstrual dysphoric disorder.Intervention 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.Main outcome measures 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.Results From 2 August 2018 to 3 December 2020, 150 women were randomly allocated to TAU (n=50), OLP– (n=50), and OLP+ (n=50), of whom 145 (96.7%) completed trial participation. Groups differed in symptom intensity (F(4)=4.419, p=0.002, r 2=0.16) and interference (F(4)=3.159, p=0.014, r2=0.13) across three MCs. Mean symptom intensity at MC3 was lower for OLP+ compared to TAU (b=–9.97, SE=2.85, t(412)=3.50, p<0.001, d=0.90) and to OLP– (b=–6.10, SE=2.89, t(411)=2.11, p=0.036, d=0.55), but OLP– and TAU did not differ (b=–3.87, SE=2.87, t(411)=1.35, p=0.177, d=0.35). Mean interference at MC3 was lower for OLP+ compared to TAU (b=–1.23, SE=0.54, t(443)=2.30, p=0.022, d=0.55) and to OLP– (b=–1.10, SE=0.54, t(442)=2.02, p=0.044, d=0.48), but OLP– and TAU did not differ (b=–0.14, SE=0.54, t(442)=0.26, p=0.799, d=0.06). Four non-serious adverse events were reported in OLP– (n=1) and OLP+ (n=3). Improvement in psychological and somatic symptom intensity was comparable to primary outcomes. Adherence to the OLP intervention was high (93.18±18.95%), with no difference between groups.Conclusions The results of our clinical trial indicate that OLP provided with a treatment rationale is an effective, safe, and acceptable treatment for PMS.Trial registration ClinicalTrials.gov NCT03547661 (submitted 2 May 2018).",
  "authors": [
    {
      "affiliations": [
        "Division of Clinical Psychology and Psychotherapy, Faculty of Psychology, University of Basel, Basel, Switzerland"
      ],
      "name": "Antje Frey Nascimento"
    },
    {
      "affiliations": [
        "Division of Clinical Psychology and Psychotherapy, Faculty of Psychology, University of Basel, Basel, Switzerland"
      ],
      "name": "Jens Gaab"
    },
    {
      "affiliations": [
        "Division of Clinical Psychology and Psychotherapy, Faculty of Psychology, University of Basel, Basel, Switzerland"
      ],
      "name": "Bojana Degen"
    },
    {
      "affiliations": [
        "Division of Clinical Psychology and Psychotherapy, Faculty of Psychology, University of Basel, Basel, Switzerland"
      ],
      "name": "Mareike Rytz"
    },
    {
      "affiliations": [
        "Division of Clinical Psychology and Psychotherapy, Faculty of Psychology, University of Basel, Basel, Switzerland"
      ],
      "name": "Anja Holder"
    },
    {
      "affiliations": [
        "Division of Clinical Psychology and Psychotherapy, Faculty of Psychology, University of Basel, Basel, Switzerland",
        "Nephrology, University Hospital Basel, Basel, Switzerland"
      ],
      "name": "Dilan Sezer"
    },
    {
      "affiliations": [
        "Division of Clinical Psychology and Psychotherapy, Faculty of Psychology, University of Basel, Basel, Switzerland"
      ],
      "name": "Sarah Buergler"
    },
    {
      "affiliations": [
        "Division of Clinical Psychology & Epidemiology, University of Basel, Basel, Switzerland"
      ],
      "name": "Andrea H Meyer"
    },
    {
      "affiliations": [
        "Program in Placebo Studies, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA"
      ],
      "name": "Irving Kirsch"
    },
    {
      "affiliations": [
        "Department of Anesthesiology, Critical Care & Pain Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA"
      ],
      "name": "Joe Kossowsky"
    },
    {
      "affiliations": [
        "Department of Consultation-Liaison Psychiatry and Psychosomatic Medicine, University Hospital Zurich, University of Zurich, Zurich, Switzerland",
        "Clinical Psychology and Psychosomatics, Faculty of Psychology, University of Basel, Basel, Switzerland"
      ],
      "name": "Cosima Locher"
    }
  ],
  "title": "Efficacy of open-label placebos for premenstrual syndrome: a randomised controlled trial",
  "uid": "4e5e03c4-884b-54c1-a98a-dabd084b910f"
}