Abstract

Post-market pharmaceutical surveillance or ‘pharmacovigilance’ relies on the reporting of suspected adverse drug reactions to regulatory databases. Recently, more ‘active’ methods that directly involve patients in identifying and reporting suspected adverse drug reactions have been suggested. This is different than traditional ‘passive’ methods, e.g., using databases without contacting patients directly. Though there are benefits to active pharmacovigilance, it is not without its potential risks. Here I highlight one of those risks – the nocebo effect. Nocebo effects are harms that are thought to arise by conditioning or negative expectation. If a patient engaged in active pharmacovigilance is improperly motivated to seek out and report suspected adverse drug reactions, nocebo harms can occur. Not only is this a bioethical concern about harm, but it is also an epistemic or data-quality problem. Since nocebo effects are not due to the pharmacological properties of the drugs under investigation, nocebo effects reported as suspected adverse drug reactions constitute false positives in these databases.