Trial reportPsychopharmacology2018
The effect of dopamine on conditioned placebo analgesia in healthy individuals: a double-blind randomized trial.
Trial report in Psychopharmacology, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 9 papers, 1 of them a synthesis 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
9 citing papers in PubMed, 1 synthesis or guideline pooled it, 14 citations in OpenAlex.
- Pooled it
- Upregulation of reward mesolimbic activity and immune response to vaccination: a randomized controlled trial.Nature medicine · 2026Trial
- Dopamine has no direct causal role in the formation of treatment expectations and placebo analgesia in humans.PLoS biology · 2024Trial
- Effects of Oxytocin on Placebo and Nocebo Effects in a Pain Conditioning Paradigm: A Randomized Controlled Trial.The journal of painTrial
- Dose-extending placebo effect in a rat model of buprenorphine maintenance treatment.Psychopharmacology · 2026Article
- Generalisation of Placebo and Nocebo Effects: Current Knowledge and Future Directions.European journal of pain (London, England) · 2025Review
- [Placebo effects in analgesia : Influence of expectations on the efficacy and tolerability of analgesic treatment].Schmerz (Berlin, Germany) · 2023Review
- Acquisition learning is stronger for aversive than appetitive events.Communications biology · 2022Article
- Mesocorticolimbic Pathways Encode Cue-Based Expectancy Effects on Pain.The Journal of neuroscience : the official journal of the Society for Neuroscience · 2020Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors at 1 institution in 1 country.
Funding
Abstract
rationaleBetter means to control placebo effects are key to optimizing treatment outcomes. Dopamine-based reward and learning mechanisms have been hypothesized to drive placebo effects. Here, we tested whether dopamine augmentation can modulate learned placebo effects.
methodsWe performed a randomized, double-blind parallel group study with 70 healthy adult participants to test whether a single oral dose of the dopamine precursor levodopa/carbidopa (100/25 mg) administered before the acquisition of conditioned placebo analgesia enhances the placebo response in an established experimental placebo model using heat pain.
resultsOverall, the observed levels of placebo analgesia in our sample were low and not statistically significant. Levodopa, compared to placebo, only led to a marginal increase in placebo analgesia. Female participants tended to show larger placebo responses than male participants. Within the female subgroup, levodopa showed small-to-moderate effects on placebo analgesia; however, this effect was not statistically significant.
conclusionsIn summary, the present study could not provide evidence for a placebo augmenting effect of levodopa-enhanced dopamine levels in healthy subjects. Further studies are needed to elucidate whether placebo enhancement can be achieved through dopamine augmentation.
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.