The nocebo effect: indexed research register 2020–2026

Article overview

A provenance-preserving register of the peer-reviewed literature Europe PMC indexes for the nocebo effect, with publication types, journal spread and anchor records that any reader can resolve by DOI.

What this register counts

This page reports how much peer-reviewed literature is indexed on the nocebo effect, not what that literature concludes. Every headline number comes from a live query against the whole Europe PMC index for the term “nocebo effect”, restricted to a first publication date between 2020-01-01 and 2026-07-30, and each query is published as a link you can open and re-run. On 2026-07-30 the term resolved to 1,866 records. These are complete counts over the index, not estimates and not a sample. A catalogue count is still a measurement of a catalogue, and a catalogue is not the state of knowledge.

Publication types and access

Publication type comes from the index metadata rather than from any reading of the articles. Of the 1,866 records, the index types 564 as a review or meta-analysis and 183 as a randomised controlled trial. 1,377 records are flagged open access, which means their full text can be read without payment and a reader can check any statement against the source. Records may carry more than one type, and records with no type assigned are counted in the total but in neither category, so the categories do not sum to the total and were never intended to.

How the literature is distributed

Counts by publication year run 2020: 202, 2021: 276, 2022: 334, 2023: 275, 2024: 290, 2025: 322, 2026: 163, with 2022 the heaviest year in the window. Within the 201 records Metatron Health holds in its dated local snapshot of 2026-07-30, the literature spans 155 distinct journals, led by: BMJ open (5 records), PloS one (5 records), Journal of clinical medicine (5 records), Pain (4 records), Nutrients (3 records). That journal breakdown describes the captured snapshot rather than the full index, and is offered as an orientation to where this field publishes, not as a complete ranking.

What this register does not establish

A record count is not evidence of benefit, and being indexed is not endorsement by anyone, including us. This page carries no effect estimate, no comparison between treatments, no dose and no recommendation. A large literature can be large because a question is hard, commercially interesting, or repeatedly studied at low quality, and a captured subset can over-represent whichever records the index returned first. Anyone using this register to decide what to take or which practitioner to see is using it for something it was not built to do.

Anchor records and how to verify them

Each register names anchor records that a reader can resolve independently: Pain (2026); International review of neurobiology (2025); eLife (2025); BMC complementary medicine and therapies (2025). Anchors are selected deterministically, favouring reviews and trials, then open access, then citation count, with one record per journal. Records carrying a retraction or withdrawal notice in the index are excluded. Every anchor carries a DOI, its indexed grant support and its correction state as observed on 2026-07-30. Before this page was published, an independent review lane resolved every source URL listed below and recorded the hash of what it received.

Machine-readable reviewed statements

Sources and governing contracts

• SRC-EPMC-INDEX-NOCEBO-EFFECT — Europe PMC, EMBL-EBI, Europe PMC search index, records of any type: "nocebo effect" AND FIRST_PDATE:[2020-01-01 TO 2026-07-30]. Role: bibliographic index. Public literature index operated by EMBL-EBI. Metatron Health has no commercial or editorial relationship with the index operator and receives no payment connected to what it indexes. Open source
• SRC-EPMC-REVIEWS-NOCEBO-EFFECT — Europe PMC, EMBL-EBI, Europe PMC search index, records typed as a review or meta-analysis: "nocebo effect" AND FIRST_PDATE:[2020-01-01 TO 2026-07-30] AND PUB_TYPE:"Review". Role: bibliographic index. Public literature index operated by EMBL-EBI. Metatron Health has no commercial or editorial relationship with the index operator and receives no payment connected to what it indexes. Open source
• SRC-EPMC-TRIALS-NOCEBO-EFFECT — Europe PMC, EMBL-EBI, Europe PMC search index, records typed as a randomised controlled trial: "nocebo effect" AND FIRST_PDATE:[2020-01-01 TO 2026-07-30] AND PUB_TYPE:"Randomized Controlled Trial". Role: bibliographic index. Public literature index operated by EMBL-EBI. Metatron Health has no commercial or editorial relationship with the index operator and receives no payment connected to what it indexes. Open source
• SRC-EPMC-OPENACCESS-NOCEBO-EFFECT — Europe PMC, EMBL-EBI, Europe PMC search index, records whose full text is free to read: "nocebo effect" AND FIRST_PDATE:[2020-01-01 TO 2026-07-30] AND OPEN_ACCESS:y. Role: bibliographic index. Public literature index operated by EMBL-EBI. Metatron Health has no commercial or editorial relationship with the index operator and receives no payment connected to what it indexes. Open source
• SRC-EPMC-NOCEBO-EFFECT-01 — Pain, Unraveling nocebo effects in visceral pain: negative suggestion and adverse treatment experience uniquely shape visceral pain unpleasantness. Role: independent research. Independent peer-reviewed article. Metatron Health has no financial or editorial relationship with its authors, journal or funders and earns nothing from citing it. Open source
• SRC-EPMC-NOCEBO-EFFECT-02 — International review of neurobiology, Clinical neuroscience and neurobiology of placebo and nocebo effects. Role: independent research. Independent peer-reviewed article. Metatron Health has no financial or editorial relationship with its authors, journal or funders and earns nothing from citing it. Open source
• SRC-EPMC-NOCEBO-EFFECT-03 — eLife, Nocebo effects are stronger and more persistent than placebo effects in healthy individuals. Role: independent research. Independent peer-reviewed article. Metatron Health has no financial or editorial relationship with its authors, journal or funders and earns nothing from citing it. Open source
• SRC-EPMC-NOCEBO-EFFECT-04 — BMC complementary medicine and therapies, Chinese medicine (Tiao-Chang Ke-Min granules) placebo and nocebo effects for diarrhea-predominant irritable bowel syndrome: a study protocol for a randomized controlled trial based on a balanced experimental design. Role: independent research. Independent peer-reviewed article. Metatron Health has no financial or editorial relationship with its authors, journal or funders and earns nothing from citing it. Open source