Interventions that inform patients about nocebo effects: A systematic review of the current evidence

The disclosure of side-effect information can negatively contribute to one's health by giving rise to nocebo side-effects, in which simply learning about potential side-effects increases their occurrence. Nocebo side-effects can decrease treatment adherence, and reduce quality of life, so it is valuable to establish interventions to decrease nocebo effects. One promising method is to inform individuals about the nocebo effect, termed nocebo education.

A systematic review following the PRISMA guidelines was conducted across databases, including PubMed, Web of Science, and PsychInfo, to summarize and assess the results of research that has administered nocebo education as an intervention.

We identified 18 records with 21 studies that met the criteria of controlled experiments manipulating nocebo education. Six experiments included patient-only samples (cancer patients, depressive disorder patients), with 5 resulting in evidence for symptom and/or psychological changes induced by nocebo education. Fifteen experiments included subpatient or nonpatient samples, with 11 resulting in either significant symptom, behavioral, and/or psychological changes from nocebo education. Effect sizes were highly variable across studies.

The studies provide preliminary support that nocebo education can reduce side-effects and change possible mechanisms of action underlying nocebo effects from side effect disclosure. The main conclusion, however, is that presently, the literature is quite limited and there is a need for additional research testing the impact of nocebo education on side effect symptoms, particularly in patient samples. We close the review by discussing unanswered questions, conflicting results, and potential strategies for optimizing future interventions.