Research on open-label placebos questions whether deception is a necessary characteristic of placebo effects. Yet, comparisons between open-label and deceptive placebos (DPs) are lacking. We therefore assessed effects of open-label placebos and DPs in comparison with no treatment (NT) with a standardized experimental heat pain paradigm in a randomized controlled trial in healthy participants. Participants (N = 160) were randomly assigned to NT, open-label placebo without rationale (OPR-), open-label placebo with rationale (OPR), and DP. We conducted baseline and posttreatment measurements of heat pain threshold and tolerance. Apart from the NT, all groups received an application of a placebo cream. Primary outcomes were planned comparisons of heat pain tolerance and the corresponding intensity and unpleasantness ratings. Objective posttreatment pain tolerance did not differ among groups. However, for subjective heat pain ratings at the posttreatment tolerance level, groups with a rationale (OPR and DP) reported diminished heat pain intensity (t(146) = -2.15, P = 0.033, d = 0.43) and unpleasantness ratings (t(146) = -2.43, P = 0.016, d = 0.49) compared with the OPR-group. Interestingly, the OPR and the DP groups did not significantly differ in heat pain intensity (t(146) = -1.10, P = 0.272) or unpleasantness ratings (t(146) = -0.05, P = 0.961) at the posttreatment tolerance level. Our findings reveal that placebos with a plausible rationale are more effective than without a rationale. Even more, open-label placebos did not significantly differ in their effects from DPs. Therefore, we question the ubiquitously assumed necessity of concealment in placebo administration.

Objective: Highly distressed cancer patients often do not use psycho-oncological services (POS). Research on predictors of POS uptake has mainly focused on patient-related variables and less on communication variables, so we examined the link between patient-oncologist communication (ie, talking about psychosocial distress, providing detailed information, and recommending POS) and POS uptake. Methods:We conducted a prospective, observational study in an Oncology Outpatient Clinic in Switzerland. Predictors (ie, patient-related variables and patient's reports of the patient-oncologist communication) were assessed via semistructured interviews, and information on outpatient POS uptake was assessed after 4 months.For statistical analysis, a multivariate logistic regression was performed.Results: Of 333 participants (mean age 61 years; 55% male; 54% distress thermometer ≥5), 77 (23%) had used POS during a 4-month period. Patients who reported an oncologist-recommended POS (odds ratio [OR] = 6.27, 95% confidence interval [CI] = 3.14-12.85) and those who were not sure if they had received a recommendation (OR = 4.64, 95% CI = 1.83-11.97) were more likely to attend POS than those who reported receiving no recommendation. Talking about psychosocial distress (OR = 0.74, 95% CI = 0.38-1.46) and providing detailed information about POS did not predict POS uptake (OR = 1.06, 95% CI = 0.46-2.38). Conclusions:Oncologists' expert recommendations to attend POS were strongly associated with patients' uptake of POS. The central role played by oncologists should be accounted for in stepped psycho-oncological care when POS referral pathways are defined.

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IntroductionRecent evidence suggests that for certain clinical conditions, placebos can improve clinical outcomes even without deception. These so-called open-label placebos (OLPs) bear the advantage of a significant lower risk of adverse events and comply with ethical principles. Although premenstrual syndrome (PMS) seems to be considerably susceptible to placebo effects, no study has examined open-OLP responses on PMS.Methods and analysisTo test the efficacy of OLPs in women suffering from PMS, a clinical randomised controlled trial including two OLP study groups (with and without treatment rationale) was designed to investigate on the effect on PMS. PMS symptoms are monitored on a daily basis via a symptom diary, adverse events are monitored intermittently. The study started in spring 2018 and patients will be included until a maximum of 150 participants are randomised. Besides the primary outcome PMS symptom intensity and interference, an array of further variables is assessed. Multilevel modelling will be used for data analyses.Ethics and disseminationEthics approval was obtained from the Ethics Committee Northwest and Central Switzerland. Results of the main analysis and of secondary analyses will be submitted for publication in peer-reviewed journals.Trial registration numbers(1) ClinicalTrials.gov (NCT03547661); (2) Swiss national registration (SNCTP000002809).

ObjectivesTo analyse participants’ concepts about the open-label placebo (OLP) effect; to explore their views about the discussion points that are applied in conventional OLP trials and to examine their experiences of taking part in an OLP trial.DesignA qualitative study using thematic analysis of semistructured interviews that were nested within a randomised controlled trial investigating experimental OLP analgesia (registered at ClinicalTrials.gov: NCT02578420).Participants30 healthy adults who took part in the randomised controlled trial.ResultsParticipants mostly conceptualised placebo as something that is inert and requires deception in order to be effective. Interviewees used a broad definition of placebos, going beyond a conventional notion of sugar pills. In contrast to the conventional OLP rationale, participants seldom emphasised classical conditioning as a mechanism of placebo effects, stressing a variety of other well-established components through which placebos might be therapeutic, whereas the conventional OLP disclosures state that ‘a positive attitude helps but is not necessary’, participants in our study applied other attitudes, such as ‘it’s worth a try’. When asked about their experiences during the trial, the majority emphasised that the concept of OLP was completely novel to them. Participants were rather sceptical about the efficacy of the intervention.ConclusionIntegrating lay perspectives into the scientific rationale of OLP treatments might enhance the plausibility and credibility of the rationale in ethical treatments.Trial registration numberNCT02578420.