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Research Letter
May 2014

Medical Conspiracy Theories and Health Behaviors in the United States

Author Affiliations
  • 1Department of Political Science, University of Chicago, Chicago, Illinois
JAMA Intern Med. 2014;174(5):817-818. doi:10.1001/jamainternmed.2014.190

Over the past 50 years, numerous conspiracy theories have materialized around public health matters such as water fluoridation, vaccines, cell phones, and alternative medicine. What remains unclear is whether the American public supports these conspiracy theories or whether they correlate with actual health behaviors.


To determine the extent of “medical conspiracism” in the American public, a nationally representative, online-survey sample of 1351 adults was collected in August and September of 2013 by Internet market research company YouGov. The survey results were then weighted to provide a representative sample of the population and have the same degree of accuracy as in-person or telephone surveys.1 This research was approved by the institutional review board of the University of Chicago. Respondents who took part in the survey gave their written consent.


Table 1 lists the proportions of Americans who report having heard of 6 popular medical conspiracy theories (the full wording is in the table) and their levels of agreement with each. Conspiracy theories about cancer cures, vaccines, and cell phones are familiar to at least half of the sample. These theories also enjoy relatively large levels of support: 37% of the sample agreed that the Food and Drug Administration is intentionally suppressing natural cures for cancer because of drug company pressure; 20% agreed either that corporations were preventing public health officials from releasing data linking cell phones to cancer or that physicians still want to vaccinate children even though they know such vaccines to be dangerous. Conspiracy theories about water fluoridation, genetically modified foods, and the link between the human immunodeficiency virus and the US Central Intelligence Agency were less well known: less than one-third of the sample said that they had heard of these conspiracy narratives and only 12% of respondents agreed with each. In sum, 49% of Americans agree with at least 1 medical conspiracy theory and 18% agree with 3 or more. These percentages are largely consistent with those found by surveys about political conspiracy theories.2

These conspiracist beliefs, in turn, are correlated with a variety of health behaviors. Table 2 list the proportion of respondents engaging in various health activities by the number of medical conspiracies they believe in, either none, 1 or 2 (“low conspiracists”), or 3 or more (“high conspiracists”). The survey indicates that conspiracism correlates with greater use of alternative medicine and the avoidance of traditional medicine. High conspiracists were more likely to buy farm stand or organic foods and use herbal supplements; conversely, they were less likely to use sunscreen or get influenza shots or annual checkups. For example, whereas 20% of the total sample reported using herbal supplements, 35% of high conspiracists do. And whereas 45% of the total sample reported getting annual physical examinations, only 37% of the high conspiracists do. Subsequent multivariate analysis that controls for socioeconomic status, paranoia, and general social estrangement indicates that medical conspiracism remains a robust predictor of these health behaviors.


Although it is common to disparage adherents of conspiracy theories as a delusional fringe of paranoid cranks, our data suggest that medical conspiracy theories are widely known, broadly endorsed, and highly predictive of many common health behaviors. Rather than viewing medical conspiracism as indicative of a psychopathological condition, we can recognize that most individuals who endorse these narratives are otherwise “normal” and that conspiracism arises from common attribution processes.2 Medical conspiracism may also be a diagnostic tool for health practitioners because conspiracists are less willing to follow traditional medical advice, such as using sunscreens or vaccines, and are more likely to use alternative treatments.

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Article Information

Corresponding Author: J. Eric Oliver, PhD, Department of Political Science, University of Chicago, 518 Pick Hall, 5828 S University Ave, Chicago, IL 60637 (eoliver@uchicago.edu).

Published Online: March 17, 2014. doi:10.1001/jamainternmed.2014.190.

Author Contributions: Dr Oliver had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: Both authors.

Acquisition of data: Oliver.

Analysis and interpretation of data: Both authors.

Drafting of the manuscript: Oliver.

Critical revision of the manuscript for important intellectual content: Both authors.

Statistical analysis: Both authors.

Obtained funding: Oliver.

Conflict of Interest Disclosures: None reported.

Ansolabehere  S, Schaffner  BF.  Does survey mode still matter? findings from a 2010 multi-mode comparison. Social Science Research Network website. http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1868229. Published 2011. Accessed February 6, 2014.
Oliver  JE, Wood  T.  Conspiracy theories and the paranoid style(s) of mass opinion.  Am J Pol Sci. In press.