Placebo prevents rumination: An experimental study

Abstract

BackgroundRumination is a risk factor for the development and maintenance of depressive symptoms and represents an important target for the treatment of depression. In the present study, we aimed to examine whether rumination can be reduced when participants are led to believe that they would receive medication that would prevent them from ruminating. MethodsIn healthy participants (N= 91), an initial dysphoric state was induced via mood-suggestive music and autobiographic recall. Subsequently, participants were randomly assigned to one of two groups: an experimental group that received a deceptive active placebo via intranasal application accompanied by expectancy-enhancing instructions vs. a no-treatment control group. Then, rumination was induced via a rumination-activating task. The primary outcome was current rumination; experienced sadness was considered a secondary outcome. ResultsConsistent with the hypothesis, participants receiving the placebo reported a significantly lower increase in current rumination (d= 0.57) and a higher decrease in sadness (d= 0.69) after the experimental induction than the control group. LimitationsThe external validity of this study might be limited due to the highly educated student sample. ConclusionsThe results suggest that rumination processes as well as experienced sadness can be positively influenced by placebo treatment. To evaluate its clinical potential, placebo-induced expectancy effects in rumination research should be further examined, particularly with clinically depressed patients. Also, the results imply that clinicians might consider the effects of expectations on patients’ rumination tendencies, for example by explicitly addressing patients’ expectations about rumination, mood, and the treatment in general.