It is one of the most astonishing discoveries in recent placebo research: placebos can be effective even when patients know that they are receiving a pill without any active ingredient. Many people are even open to consciously taking such so-called open-label placebos (OLPs) as their treatment.
Several members of the CRC/TRR 289 are researching whether and how OLPs could complement established therapies—especially when conventional treatments do not have the desired effect. A team led by Katarina Forkmann from Essen University Hospital has now asked patients what such an OLP therapy would need to look like in order to be as effective as possible. The responses, recently published in the Journal of Psychosomatic Research, were surprisingly nuanced:
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In general, respondents found round, white pills to be the most attractive and convincing, and attributed the greatest effect to them. However, other shapes were preferred for different symptoms.
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The respondents would prefer to take the placebo once a day. However, they expected the greatest effect from taking it twice a day.
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The participants would pay the most for placebo therapy for chronic pain, sleep disorders, or mood improvement.
The dosage form of OLPs can be optimized for individual areas of application
The responses depended largely on the participants' previous experiences and the assumed area of application of the placebos. The researchers therefore recommend optimizing the dosage form of the pills for the condition being treated when conducting trials with OLPs. For example, it may make sense for OLPs for conditions for which prominent drugs already exist (e.g., for pain or sleep disorders) to resemble existing medications. If, on the other hand, symptoms are less strongly associated with a particular type of medication (e.g., for improving cognition or treating fatigue), other factors such as attractiveness to patients could be taken into account.
However, according to the authors, it should be noted that the specific preferences and expectations of patients are likely to vary from country to country and are influenced by the usual pill shapes, previous expectations, and knowledge about the treatment.