Can medical conspiracies influence health behaviors?

By Naveed Saleh, MD, MS, for MDLinx
Published August 21, 2019

Key Takeaways

Medical conspiracy theories often portray medical, science, or technology-related issues as under the influence of secret societies, with these issues posing harm to the public. For example, a common medical conspiracy theory holds that water fluoridation is used to hide the existence of pollutants.

Let’s take a look at a couple of studies on medical conspiracy theories.


Physicians are trained to be grounded in the facts. So, it may be easy for doctors to dismiss conspiracy theories as a fringe delusion spread by people who are paranoid. But in a study published in JAMA Internal Medicine, researchers found that many Americans are aware of conspiracy theories and endorse them. Moreover, medical conspiracy theories are highly predictive of 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,” wrote the authors.

Medical conspiracy narratives

In this study, 1,351 adult Americans were surveyed online to determine the extent of “medical conspiracism” using a nationally representative, online survey. The participants were asked whether they had heard about six popular medical conspiracy theories, and whether they agreed with them.

Here are the theories and results:

  1. “The Food and Drug Administration is deliberately preventing the public from getting natural cures for cancer and other diseases because of pressure from drug companies.”
  • Previously heard: 63%
  • Agree with: 37%
  • Disagree with: 32%
  • Neither: 31%
  1. “Health officials know that cell phones cause cancer but are doing nothing to stop it because large corporations won’t let them.”
  • Previously heard: 57%
  • Agree with: 20%
  • Disagree with: 40%
  • Neither: 40%
  1. “The CIA deliberately infected large numbers of African Americans with HIV under the guise of a hepatitis inoculation program.”
  • Previously heard: 32%
  • Agree with: 12%
  • Disagree with: 51%
  • Neither: 37%
  1. “The global dissemination of genetically modified foods by Monsanto Inc. is part of a secret program, called Agenda 21, launched by the Rockefeller and Ford Foundations to shrink the world’s population.”
  • Previously heard: 19%
  • Agree with: 12%
  • Disagree with: 42%
  • Neither: 46%
  1. “Doctors and the government still want to vaccinate children even though they know these vaccines cause autism and other psychological disorders.”
  • Previously heard: 69%
  • Agree with: 20%
  • Disagree with: 44%
  • Neither: 36%
  1. “Public water fluoridation is really just a secret way for chemical companies to dump the dangerous byproducts of phosphate mines into the environment.”
  • Previously heard: 25%
  • Agree with: 12%
  • Disagree with: 46%
  • Neither: 41%


Health behaviors

The researchers also looked at whether the number of conspiracy theories that participants believed were related to their health behaviors. They found that people who agreed with three or more medical conspiracies (high conspiracists) were more likely to buy organic or farm stand foods and use herbal supplements, but they were less likely to use sunscreen, get flu shots, or go for annual checkups. Here’s the breakdown:

  1. Taking herbal supplements
  • Respondents who use herbal supplements: 20%
  • 0 conspiracy theories held: 13%
  • 1 or 2 conspiracy theories held: 22%
  • ≥ 3 conspiracy theories held: 35%
  1. Buying local/farm stand food
  • Respondents who buy local/farm stand food: 23%
  • 0 conspiracy theories held: 14%
  • 1 or 2 conspiracy theories held: 30%
  • ≥ 3 conspiracy theories held: 37%
  1. Prioritizing organic food consumption
  • Respondents who prioritize organic food consumption: 21%
  • 0 conspiracy theories held: 18%
  • 1 or 2 conspiracy theories held: 22%
  • ≥ 3 conspiracy theories held: 24%
  1. Taking vitamins
  • Respondents who take vitamins: 57%
  • 0 conspiracy theories held: 54%
  • 1 or 2 conspiracy theories held: 61%
  • ≥ 3 conspiracy theories held: 58%
  1. Going for annual physical examination
  • Respondents who get an annual physical exam: 45%
  • 0 conspiracy theories held: 48%
  • 1 or 2 conspiracy theories held: 46%
  • ≥ 3 conspiracy theories held: 37%
  1. Receiving influenza shot
  • Respondents who get a flu shot: 35%
  • 0 conspiracy theories held: 39%
  • 1 or 2 conspiracy theories held: 36%
  • ≥ 3 conspiracy theories held: 25%
  1. Visiting dentist
  • Respondents who go to the dentist: 41%
  • 0 conspiracy theories held: 44%
  • 1 or 2 conspiracy theories held: 39%
  • ≥ 3 conspiracy theories held: 33%
  1. Using sunscreen
  • Respondents who use sunscreen: 35%
  • 0 conspiracy theories held: 38%
  • 1 or 2 conspiracy theories held: 34%
  • ≥ 3 conspiracy theories held: 30%

Modern health worries

In a separate study in the Journal of Psychosomatic Research, investigators examined whether medical conspiracy theories plus other variables, such as demographics, ideology, and health perceptions, are linked to “modern health worries,” which refer to “perceived risk to personal health from technological changes and features of modern life.”

In total, 335 British participants were surveyed online. The investigators found that elderly people with more religious and right-wing beliefs had more modern mental health worries. Furthermore, those who engaged in complementary and alternative medicine practices, as well as people who thought their mental health was worse vs their peers, were more likely to have more modern mental health worries.

The authors concluded: “Belief in MCTs [medical conspiracy theories] has been shown to affect health behaviours and choices, eg, the choice to avoid vaccinating or use CAM [complementary alternative medicine]. Having this information would help doctors and health professionals better understand their patient’s beliefs and views about modern medicine so they can present more patient-tailored information and advice. This in turn may increase patient satisfaction as well as compliance or adherence to medical advice.”

On a final note, patient belief in medical conspiracy theories could even serve as a test. According to the authors of the JAMA Internal Medicine study, conspiracy theories could be used as a diagnostic tool for physicians because patients who believe them may be less likely to follow conventional medical advice, such as using sunscreen and vaccines, and instead be more likely to engage in complementary or alternative medicine.


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