Effects of placebo interventions on gastric motility and general autonomic activity

Objective

The study aimed to investigate placebo effects on gastric motility and to examine possible autonomic mediating mechanisms.

Methods

Eighteen healthy volunteers received a placebo pill on three occasions together with the verbal suggestion that it would stimulate, relax, or not affect gastric activity. Electrogastrogram, electrocardiogram, and electrodermal activity recordings were conducted for 30 min prior to and following intervention.

Results

Dominant frequency of the gastric slow wave decreased in the stimulant condition, and increased in the relaxant condition, the difference among conditions being significant. No differential effects of the interventions on cardiac interbeat intervals, heart rate variability, and skin conductance levels were observed.

Conclusion

Stomach relaxant and stimulant placebo interventions modulated gastric motility independently from changes in general autonomic activity.