Vambheim SM, et al. – In this review, the clinicians aimed to examine whether there were systematic sex differences in the placebo and the nocebo effect. They demonstrated that in the placebo and nocebo effects, there were sex differences, probably caused by sex differences in stress, anxiety, and the endogenous opioid system.

• The clinicians conducted a literature search in multiple electronic databases.
• They included studies if the study compared a group or condition where a placebo was administered to a natural history group or similar cohort.

• The clinicians identified 18 studies - 12 on placebo effects and 6 on nocebo effects.
• Chi-square tests demonstrated that :
  • Males responded more strongly to placebo treatment, and females responded more strongly to nocebo treatment
  • Males responded with larger placebo effects induced by verbal information, and females responded with larger nocebo effects induced by conditioning procedures.