According to co-primary investigators, Julia W. Haas and Giulio Ongaro, recent literature has increasingly proposed that open-label placebo (OLP) is an effective treatment for several disorders based on patient-reported outcomes. However, Haas, Ongaro, and colleagues found that there were no published studies on the patients’ qualitative perceptions in OLP studies, nor any studies that compared OLP and double-blind placebo (DBP) experiences. They examined how patients experience these treatments in a study published in BMC Psychology.

The study was nested within a larger randomized controlled trial which compared OLP and DBP treatments in patients with irritable bowel syndrome (IBS). Thirty-three patients in the parent trial were interviewed about their experiences. Qualitative data from those interviews were compared to quantified IBS severity scores from the patient trial with a mixed-methods model.

Two prominent themes were recorded in the interviews: “the participants’ feelings about their treatment allocation and their reflections about the treatment.” Additionally, both OLP and DBP groups mentioned hope and curiosity as major factors in their engagement with treatment. The investigators added that, “while DBP participants tended to be more enthusiastic about their allocation, OLP participants were more ambivalent,” and that “OLP participants reflected more on their treatment, often involving noticeable cognitive and emotional processes of self-reflection.” A variety of explanations for the OLP improvements were provided by patients, and they “were significantly less likely to attribute it to the treatment itself than DBP participants (Χ2 [3] = 8.28; p = 0.041). Finally, retrospective descriptions of symptom improvement were significantly correlated with associated IBS severity scores for the DBP interviewees, but not for the OLP interviewees.

The researchers wrote of the results, “the counter-intuitive OLP prompts more self-examination, ambivalent feelings, and active engagement compared to DBP,” though they added that “OLP participants are more reluctant to attribute symptom improvement to their treatment.” They concluded that “OLP and DBP participants share feelings of hope, uncertainty and curiosity but differ in the extent of conscious reflection.”