Does the nocebo effect mean the symptoms are imagined?

Question

Researchers say EHS symptoms are a nocebo effect — does that mean they aren't real?

Answer

No. Nocebo describes a mechanism, not a verdict on whether someone is suffering: expecting harm can produce measurable physiological symptoms, and those symptoms are as real as any other. The review evidence — 46 blinded provocation experiments with 1175 volunteers — is that symptoms did not track whether the field was actually on, while they did track what participants believed, and the same reviews are explicit that this does not make the illness imaginary. It does change what helps: if the trigger is not the field, then shielding and moving house are unlikely to resolve the symptoms, whereas clinical care of the symptoms themselves may.

Related records

• Rubin et al. 2010 — updated systematic review of EHS provocation studies

  46 blind or double-blind provocation experiments with 1175 self-reported sensitive volunteers: no robust evidence that field exposure triggered their symptoms, and support for a nocebo mechanism instead.

  Research record

• Nocebo effect

  Genuine symptoms produced by the expectation of harm rather than by the exposure itself — the inverse of the placebo effect.

  Glossary

• Is EMF sensitivity (EHS) real?

  Symptoms are recognised as genuine; blinded studies have not linked them to field exposure. WHO recommends evaluating the symptoms clinically.

  Direct answers

Sources

1. rubin-2010 Idiopathic environmental intolerance attributed to electromagnetic fields (formerly 'electromagnetic hypersensitivity'): an updated systematic review of provocation studies — Rubin GJ, Nieto-Hernandez R, Wessely S — Bioelectromagnetics 31(1):1–11, 2010. peer-reviewed, link checked 2026-08-12.
2. who-ehs Electromagnetic hypersensitivity (WHO backgrounder, December 2005; formerly Fact sheet 296) — World Health Organization, 2005. government, link checked 2026-08-12.