In this season of ‘Stranger Things,’ an SCSU professor is paying close attention to the asylum imagery. So should you.

The Netflix hit “Stranger Things” returned for a fourth season this month. As always, it is jam-packed with tropes and cliches drawn from ’80s movies. One recurring reference this season is the use of mental hospitals and asylums.

This fascinates Troy Rondinone, a professor of history at Southern Connecticut State University who wrote a book on this phenomenon: “Nightmare Factories: The Asylum in the American Imagination” (Johns Hopkins University Press, 2019).

Rondinone calls himself “a historian of culture” who has watched “literally hundreds of movies with asylums in them.” “Nightmare Factories” was his third book; his others are about popular culture visions of labor issues and boxing. He writes a blog, “The Asylum,” for Psychology Today magazine’s website, which has recently covered representations of mental health in “Frankenstein” and the recent movie “The Batman.”

“Asylum used to be a good word. It meant a safe haven,” Rondinone explains. “But it gained negative connotations, so by the 1800s, they started calling them hospitals.

“In the 1930s and ’40s there was a reform movement, and that was generally a good thing. New hospitals would be opened, with better ventilation, more restful environments. What they didn’t talk about was recidivism. By the late 1800s, the system wasn’t working. Hospitals were filling up and people were staying longer. This is when ‘the living dead’ become a metaphor for the patients and ‘heroic therapies’ like injecting serum or lobotomies were happening. They put people into a stupor but figured a stupor was good enough.”

Rondinone’s interest in cinematic presentations of asylums is American-centric, distinct from the many British, European and other perspectives. “Stranger Things” didn’t make it into his “Nightmare Factories” book (which concentrates on film, not TV), but Rondinone has followed the show faithfully and notes that it pays homage to iconic asylum scenes that he does discuss in the book.

He’s particularly struck this season by the characters Nancy and Robin visiting Pennherst Mental Hospital to talk to Victor Creel, one of the film’s evil presences. Nancy and Robin’s walk down the dark corridor and their confrontation with Creel evokes the 1991 film “Silence of the Lambs.” Creel is played by Robert Englund, who played Freddy Krueger in the “Nightmare on Elm Street” series.

“Walking down that corridor, learning from a madman, Freddy Krueger ...” Rondinone says. “It’s a movie referencing a movie referencing a movie. So meta.”

The other major mental-hospital reference in the fourth season of “Stranger Things” is when the show’s lead character Eleven is trapped in a mysterious clinic for children with extraordinary mental powers.

“It’s troped as a mental hospital,” Rondinone says. “The patients are not mentally ill, but they’re outsiders who are too difficult for society to understand. These are highly exceptional children who are being imprisoned and infantilized. It’s a colorful concept on the part of the producers — they know they’re dealing with kids, but are using all the authoritarian asylum tropes. They’re conducting experiments. And they keep them in those hospital johnnys all the time, which is ridiculous if you know how long-term health facilities operate.”

Other tropes seized upon by “Stranger Things,” according to Rondinone: “The concept of a dictatorship factory. Dungeons. Victorian era asylums. Also the ideas of breaking into and breaking out of an asylum. The asylum escape is fantastic.”

He says Eleven’s incarceration echoes “a hugely common theme that the person inside the asylum is the normal one.”

In earlier seasons of the series, Rondinone calls Eleven a “woman in white” presence, part of a legacy of ghostly and mentally disturbed figures appearing in novels and legends.

“Stranger Things” has also dealt with electroshock therapy, and there’s a recurring character of an “evil psychiatrist,” as Rondinone puts it, played by Paul Reiser, one of whose key 1980s roles was as a villain in “Aliens.”

But the dramatizations of mental health are often negative.

“I understand it’s entertainment, and I’m a big fan of the First Amendment, but these movies and images can enforce stigmas that may keep people from getting treatment.”

The professor relates to “Stranger Things” in ways beyond his historical studies of mental health.

“I was playing Dungeons & Dragons in the 1980s,” he says. “I was the kid in the basement. Even the bad hairdos, I had those, too.”

Christopher Arnott can be reached at carnott@courant.com.