The Trump administration has muzzled government experts who might contradict the president’s stated belief that mental illness — not the wide availability of guns — is the chief cause of mass shootings.

“Mental illness and hatred pull the trigger. Not the gun,” Trump said immediately after the shootings early this month in El Paso TX and Dayton OH, that killed 31 people. He has since claimed that reopening mental asylums would help stop such killings.

On the Monday following the weekend shootings, the Washington Post reports, “A Health and Human Services directive … warned communication staffers not to post anything on social media related to mental health, violence and mass shootings without prior approval.

The Post quotes “an HHS employee who spoke on the condition of anonymity” as saying he had “no doubt [the directive] was meant to prevent anybody from making any statements that might contradict the president,” adding that “it’s not typical” to require that all social media posts be cleared by senior officials.

While mental illness is sometimes a factor in mass shootings, “it is rarely a predictor,” says the Post, citing researchers who “have noted that more commonly shared attributes include a strong sense of resentment, desire for notoriety, obsession with other shooters, a history of domestic violence, narcissism and access to firearms.”

The Post notes that “other countries have similar rates of mental illness but only a fraction of U.S. fatalities from shootings. The key factor that sets the United States apart from the rest of the world, epidemiologists say, is the easy availability of guns.”

As for the notion of reopening mental asylums, the Post cites a recent study by researchers at the University of Pennsylvania that “looked at other countries that shut down their psychiatric institutions as America did and compared their rates of mass shootings,” finding no relationship between the two.