Health misinformation refers to false, inaccurate, or misleading information about human health, including diseases, treatments, nutrition, and environmental factors that influence health outcomes.
The spread of health misinformation can negatively impact individuals’beliefs, attitudes, and behaviors, potentially leading to poor health decisions and public health consequences. Misinformation often employs persuasive tactics to undermine scientific consensus and promote misconceptions.
Key Points
Rationale
The World Health Organization (WHO) has called misinformation a major threat to global health, spurring research into its prevalence and correlational impacts (Suarez-Lledo & Alvarez-Galvez, 2021; Luk et al., 2021).
However, the mere existence of misinformation doesn’t prove harm, andcorrelational dataprovides limited causal evidence (Ecker et al., 2022).
To address this, the authors systematically reviewedrandomized experimentson the causal impacts of health misinformation exposure.
They also classified the rhetorical tactics used in misinformation stimuli. Understanding both the impacts and features of misinformation can inform interventions to mitigate harm.
Method
The authors searched Medline, PsychInfo and Scopus databases using terms reflecting misinformation and RCT designs.
From the final 45 articles reporting 64 RCTs, the authors extracted data on publication year, sample characteristics, outcome variables, misinformation stimuli, and effect sizes.
Outcomes were coded using an extended Theory of Planned Behavior (TPB) framework. Misinformation stimuli were classified using the FLICC framework of science denial tactics.
Search Strategy and Terms
Generic search terms included variants of “misinformation”, “misleading”, “randomized controlled trial”, and terms for health and environmental topics.
Full search strings for each database are provided. Peer-reviewed filter was used when available. No date restrictions were applied.
Inclusion and Exclusion Criteria
Studies were included if they used anRCT designto compare exposure to health misinformation versus a neutral control and measured impacts on behavior or its psychological antecedents.
Studies comparing misinformation to debunking or other interventions without a neutral control were excluded.
Results
Most studies (60/64) used online adult samples, predominantly from the Americas and Europe. Vaccination, infectious diseases, and climate change were the topics studied the most.
Impact of Misinformation
Message Features of Health Misinformation
Insights
Overall, the results suggest that misinformation can negatively influence the psychological antecedents of health behaviors, but the effects are inconsistent and highly dependent on contextual factors such as audience characteristics and message content.
The limited evidence on behavioral impacts and the scarcity of research on certain key outcomes (e.g., emotions, trust) highlight the need for more comprehensive and ecologically valid research to fully understand the consequences of health misinformation.
However, the review reveals critical gaps. Impacts on trust, emotions, and norms are understudied relative to their theorized importance in science denial (Jylhä et al., 2022). Intentions, the strongest psychological predictor of behavior, were rarely measured for environmental behaviors.
Crucially, there is virtually no experimental evidence that exposure to misinformation changes health behavior, which is the ultimate concern.
The lack of diversity in health topics, samples, and methods is concerning. Most studies involved online American adults and vaccination. More research on nutrition, chronic diseases, substance use, and other globally burdensome issues is needed, using representative samples across ages, cultures, and nations.
Future experiments should isolate the impacts of different FLICC tactics and potential moderators like worldviews.
Longitudinal and behavioral research is essential to understanding real-world impacts. The planetary health perspective could increase relevance across ideological audiences.
Strengths
Limitations
Clinical Implications
This review provides health communicators and policymakers with crucial insights into the risks of health misinformation and common deceptive tactics.
It can guide the design of preemptive inoculation or reactive debunking interventions, especially those emphasizing scientific consensus and addressing logical flaws.
However, the lack of behavioral evidence means the societal harm of misinformation exposure remains unclear. The conditional nature of effects also means interventions must be carefully tailored to audiences. Persuasion is not one-size-fits-all.
Most importantly, this review is a roadmap for critical research gaps that must be filled to support evidence-based counter-misinformation efforts.
More diverse health issues, populations, settings and outcomes need rigorous study, especially using behavioral and longitudinal designs. Collaborations between health and environmental researchers could accelerate progress.
Communicators and scientists cannot avoid this challenge. Misinformation is undermining core foundations of public health. But this review shows the limits of current knowledge.
Far more research is needed to meet the “infodemic” with an evidence-based response.
References
Primary reference
Schmid, P., Altay, S., & Scherer, L. D. (2023). The Psychological Impacts and Message Features of Health Misinformation.European Psychologist, 28(3), 162–172.https://doi.org/10.1027/1016-9040/a000494
Other references
Ecker, U. K. H., Lewandowsky, S., Cook, J., Schmid, P., Fazio, L. K., Brashier, N., Kendeou, P., Vraga, E. K., & Amazeen, M. A. (2022). The psychological drivers of misinformation belief and its resistance to correction.Nature Reviews Psychology, 1(1), 13–29.https://doi.org/10.1038/s44159-021-00006-y
Jylhä, K., Stanley, S., Ojala, M., & Clarke, E. (2022). Science denial: A narrative review and recommendations for future research and practice.European Psychologist.
Luk, T. T., Zhao, S., Weng, X., Wong, J. Y.-H., Wu, Y. S., Ho, S. Y., Lam, T. H., & Wang, M. P. (2021). Exposure to health misinformation about COVID-19 and increased tobacco and alcohol use: A population-based survey in Hong Kong.Tobacco Control, 30(6), 696–699.https://doi.org/10.1136/tobaccocontrol-2020-055960
O’Keefe, D. J. (2002). Persuasion: Theory and Research. SAGE.
Suarez-Lledo, V., & Alvarez-Galvez, J. (2021). Prevalence of health misinformation on social media: Systematic review.Journal of Medical Internet Research, 23(1), Article e17187.https://doi.org/10.2196/17187
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Olivia Guy-Evans, MSc
BSc (Hons) Psychology, MSc Psychology of Education
Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.
Saul McLeod, PhD
BSc (Hons) Psychology, MRes, PhD, University of Manchester
Saul McLeod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.
