The neural bases of placebo effects

Citation: Wager, T. D. (2005). The neural bases of placebo effects. Current Directions in Psychological Science, 14(4), 175-179.

Full Text


Placebo effects are beneficial effects of treatment
caused not by the biological action of the treatment
but by one?s response to the treatment process itself. One
possible mechanism of placebo treatments is that they
create positive expectations, which change one?s appraisal
of the situation and may thereby shape sensory and emotional
processing. Recent brain-imaging evidence suggests
that placebo-induced expectations of analgesia increase
activity in the prefrontal cortex in anticipation of pain and
decrease the brain?s response to painful stimulation. These
findings suggest that placebo treatments can alter experience,
not just alter what participants are willing to report
about pain. To the extent that they involve neural systems
mediating expectancy and appraisal, placebo effects in
pain may share common circuitry with placebo effects in
depression, Parkinson?s disease, and other disorders.