Even when you know it is a placebo, you experience less sadness: First evidence from an experimental open-label placebo investigation (Open Data and Open Materials)

Open Data and Open Materials of: Even when you know it is a placebo, you experience less sadness: First evidence from an experimental open-label placebo investigation. Journal of Affective Disorders.

Background: Recent studies demonstrate substantial effects of deceptive placebo on experimentally induced sadness,
even on autonomic activity. Whether deception is necessary, remains to be elucidated. We investigated the
effect of an open-label placebo (OLP) treatment, i.e. an openly administered placebo delivered with a convincing
rationale for its sadness-protecting effect.
Methods: Eighty-four healthy females were randomized to an OLP group or a no-treatment control group. All
participants received the same detailed information about the OLP effect, only the OLP group received an OLP
nasal spray. Before and after the OLP intervention, participants underwent a sad mood induction procedure
combining self-deprecating statements (Velten's method) and sad music. Sadness was assessed by the Positive
and Negative Affect Schedule (PANAS-X). Autonomic activity was measured continuously.
Results: Participants in the OLP group reported a significantly attenuated increase in sadness upon mood induction
and less sadness after induction compared to the control group (d = 0.79). Regardless of intervention,
heart rate decreased during mood inductions with a more pronounced deceleration in the second mood induction.
Limitations: Generalizability is limited due to the selective sample and the reliance on an experimentally controlled
mood induction.
Conclusion: OLP treatment had a beneficial effect on perceived sadness, at least at the subjective level. Hence,
deception may not necessarily be required for placebos to modulate experienced sad mood. Investigating the
beneficial effects of OLP in (sub-)clinical samples would seem a promising and required next step towards a
clinical use of placebo-associated positive treatment expectations.