Open-label placebos provided with a treatment rationale can significantly alleviate symptoms of premenstrual syndrome, according to the results of a randomized controlled trial.
Researchers assessed the efficacy and safety of open-label placebo (OLPs) in women aged 18 to 45 years with moderate to severe premenstrual syndrome (PMS) or premenstrual dysphoric disorder.
The trial, conducted from 2018 to 2020, involved 150 participants randomized into 3 groups: treatment as usual (TAU), OLP without treatment rationale (OLP–), and OLP with treatment rationale (OLP+). The intervention consisted of taking two placebo pills daily for 6 weeks, reported Antje Frey Nascimento, MD, and colleagues.
Primary outcomes included changes in PMS symptom intensity and interference over three menstrual cycles. Results revealed that the OLP+ group experienced significantly lower symptom intensity and interference compared to TAU and OLP– groups. At the conclusion of the study, mean symptom intensity in the OLP+ group was substantially reduced compared to TAU. Similar improvements were observed for interference with daily activities.
"OLPs with treatment rationale, given twice daily for 6 weeks, decreased symptom intensity and interference of PMS considerably after 3 weeks, and maintained these effects after 6 weeks in the absence of substantial side-effects," wrote Dr. Nascimento and colleagues.
Furthermore, psychological and somatic symptoms showed comparable improvements, with adherence to the OLP regimen being high (93.18%). Only four non-serious adverse events were reported, suggesting the intervention’s safety, noted Dr. Nascimento, and colleagues, in BMJ Evidence-Based Medicine.
The success of OLPs may be linked to patient expectations and transparent communication about placebo effects. The potential of OLPs as an ethical, non-pharmacological intervention for PMS, is particularly helpful for patients seeking alternatives to standard treatments with undesirable side effects.
The authors disclosed no relevant conflicts of interest.
