Trial reportProceedings of the National Academy of Sciences of the United States of America2012
Nonconscious activation of placebo and nocebo pain responses.
Trial report in Proceedings of the National Academy of Sciences of the United States of America, 2012. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 129 papers, 5 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
129 citing papers in PubMed, 5 syntheses or guidelines pooled it, 308 citations in OpenAlex.
- Open label placebo for chronic low back pain: a systematic review and meta-analysis of randomized controlled trials.Pain management · 2025Pooled it
- The Nocebo Effect: A Review of Contemporary Experimental Research.International journal of behavioral medicine · 2022Pooled it
- Certainty of genuine treatment increases drug responses among intellectually disabled patients.Neurology · 2017Pooled it
- Placebo Responses in Genetically Determined Intellectual Disability: A Meta-Analysis.PloS one · 2015Pooled it
- Pooled it
- To Ask or Not to Ask: Does Inquiring About Participants' Expectations Influence the Placebo Effect? A Placebo Mechanism Study in Healthy Volunteers.European journal of pain (London, England) · 2026Trial
- Domain-General Neural Effects of Associative Learning and Expectations on Pain and Hedonic Taste Perception.The Journal of neuroscience : the official journal of the Society for Neuroscience · 2026Trial
- Trial
- The Power of a Good Word: Enhancing the Efficacy of Analgesics in Clinical Settings.Psychotherapy and psychosomatics · 2025Trial
- Nocebo expectations rather than placebo expectations affect topical pain relief: A randomized clinical trial.Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie · 2024Trial
- The impact of pharmaceutical form and simulated side effects in an open-label-placebo RCT for improving psychological distress in highly stressed students.Scientific reports · 2023Trial
- Savor the flavor: A randomized double-blind study assessing taste-enhanced placebo analgesia in healthy volunteers.Clinical and translational science · 2022Trial
- Trial
- The pain alarm response - an example of how conscious awareness shapes pain perception.Scientific reports · 2019Trial
- The Effectiveness of Leech Therapy in Chronic Low Back Pain.Deutsches Arzteblatt international · 2018Trial
- Trial
- Trial
- Trial
- Effects of subtle cognitive manipulations on placebo analgesia - An implicit priming study.European journal of pain (London, England) · 2017Trial
- Learning to experience side effects after antidepressant intake - Results from a randomized, controlled, double-blind study.Psychopharmacology · 2017Trial
69 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
9 authors at 4 institutions in 3 countries.
Funding
Abstract
The dominant theories of human placebo effects rely on a notion that consciously perceptible cues, such as verbal information or distinct stimuli in classical conditioning, provide signals that activate placebo effects. However, growing evidence suggest that behavior can be triggered by stimuli presented outside of conscious awareness. Here, we performed two experiments in which the responses to thermal pain stimuli were assessed. The first experiment assessed whether a conditioning paradigm, using clearly visible cues for high and low pain, could induce placebo and nocebo responses. The second experiment, in a separate group of subjects, assessed whether conditioned placebo and nocebo responses could be triggered in response to nonconscious (masked) exposures to the same cues. A total of 40 healthy volunteers (24 female, mean age 23 y) were investigated in a laboratory setting. Participants rated each pain stimulus on a numeric response scale, ranging from 0 = no pain to 100 = worst imaginable pain. Significant placebo and nocebo effects were found in both experiment 1 (using clearly visible stimuli) and experiment 2 (using nonconscious stimuli), indicating that the mechanisms responsible for placebo and nocebo effects can operate without conscious awareness of the triggering cues. This is a unique experimental verification of the influence of nonconscious conditioned stimuli on placebo/nocebo effects and the results challenge the exclusive role of awareness and conscious cognitions in placebo responses.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.