NEW YORK (Reuters Health) - About half of American adults believe in at least one medical conspiracy theory, according to new survey results.
For example, three times as many people believe U.S. regulators prevent people from getting natural cures as believe that a U.S. spy agency infected a large number of African Americans with the human immunodeficiency virus (HIV).
J. Eric Oliver, the study's lead author from University of Chicago, said people may believe in conspiracy theories because they're easier to understand than complex medical information.
"Science in general - medicine in particular - is complicated and cognitively challenging because you have to carry around a lot of uncertainty," Oliver said.
"To talk about epidemiology and probability theories is difficult to understand as opposed to 'if you put this substance in your body, it's going to be bad,'" he said.
Like the theories about conspiracies to infect African Americans with HIV and to prevent citizens from accessing alternative medicines, the other theories on the list had mistrust of government and large organizations as themes.
They include the theory that the government knows cell phones cause cancer but does nothing about it, that genetically modified organisms are being used to shrink the world's population, that routine vaccinations cause autism and that water fluoridation is a way for companies to dump dangerous chemicals into the environment.
Some 49% of the survey participants agreed with at least one of the conspiracies.
In fact, in addition to the 37% of respondents who fully agreed that U.S. regulators are suppressing access to natural cures, less than a third were willing to say they actively disagreed with the theory.
With regard to the theory that childhood vaccines cause psychological disorders like autism and the government knows it, 69% had heard the idea, 20% agreed with it and 44% disagreed.
The survey results suggest people who believe in medical conspiracy theories may approach their own health differently, the researchers said.
For example, while 13% of people who did not believe in any conspiracies took herbal supplements, 35% of those who believed in three or more theories took supplements.
Overall, the researchers say people who believed in conspiracies were more likely to use alternative medicine and to avoid traditional medicine.
Oliver said the findings may have implications for doctors.
Instead of viewing patients who believe in conspiracy theories as crazy, he said doctors should realize those patients may be less likely to follow a prescription regimen.
Patients – and physicians – say they feel the time crunch as never before as doctors rush through appointments as if on roller skates to see more patients and perform more procedures to make up for flat or declining reimbursements. 
