(CNN) Ever since mass shootings turned the national focus to gun violence two weeks ago, President Donald Trump has sought to blame anything but guns. He's pointed the finger at Hollywood for violent movies and video games and, even more, he's made the argument that people who commit mass shootings are unwell.

"It's the people that pull the trigger, not the gun that pulls the trigger so we have a very, very big mental health problem, and Congress is working on various things and I will be looking at it," Trump said Sunday in New Jersey.

His comments seemed to signal a backtrack from his openness to a new, more universal background-check system and a new focus on putting people with mental health problems into institutions.

But even mental health experts who agree that the move to eliminate psychiatric beds has gone too far say that putting people back in institutions would do nothing to curb gun violence.

Dominic Sisti is a professor at the University of Pennsylvania who co-wrote a paper titled "Bring Back the Asylum" in the Journal of the American Medical Association in 2015, but he said on Monday that the President was "proposing an idea without any actual evidence or background knowledge."

Sisti has argued that the so-called "deinstitutionalization" movement has gone too far but said reversing it isn't the answer to America's mass shootings.

"We do need more mental health beds to help people with mental illnesses," said Sisti in an email. "However, the dearth of such beds is not the cause of mass shootings, nor will increases in beds be the solution."

He pointed to research he published in June with Isabel Perera, also at Penn, on institutionalization in other countries.

"We show that many other countries closed psychiatric institutions during the period of deinstitutionalization. None even come close to the US in mass shooting frequency."

Trump has repeatedly spoken positively about the system of institutions, which was dismantled in part because of terrible abuse of patients as well as advances in treatment.

"These are people that have to be in institutions for help -- I'm not talking about as a form of a prison, I'm saying for help -- and I think it's something we have to really look at, the whole concept of mental institutions," Trump said. "I remember growing up we had mental institutions, then they were closed -- in New York, I'm talking about -- they were, many of them, closed. A lot of them were closed and all of those people were put out on the street."

But mental health advocates see deinstitutionalization in the US very differently than Trump. The reason the institutions were closed was because they didn't work, according to Chuck Ingoglia, the president and CEO of the National Council for Behavioral Health.

"Let's be perfectly clear," he said in a statement . "The president is suggesting we return to an era of forcibly warehousing people with serious mental illness. The nation tried that approach and, rightfully abandoned it decades ago because it did not work."

There has been a long-term effort to deinstitutionalize mental health treatment in the US and rely more on community-based treatment rather than long stays at psychiatric hospitals.

"It did not work because it was applying a criminal solution to a health problem," Ingoglia said. "And it did not work because it robbed people of their dignity. People living with serious mental illness need and deserve quality mental health treatment."

He said people with mental illness shouldn't be turned into scapegoats for the problem of mass violence. And he's lobbying for more funding for community behavioral health clinics

There has certainly been a decline in the number of beds at mental institutions. But the problem for Trump is that despite his rhetoric in favor of more mental health treatment, he's tried to slash funding for Medicaid , which provides mental health treatment to a large percentage of Americans who need it.

And often, people with severe mental health issues end up in prison or homeless.

After the shootings earlier this month in El Paso, Texas, and Dayton, Ohio, the American Psychiatric Association issued a statement calling the gun violence a public health crisis that needs attention. But the statement warned about the effects of stigmatizing people with mental illness.

The association, too, called for additional funding for mental health programs.