M. Night Shyamalan’s upcoming film is about a man with 23 different personalities who abducts a group of girls and proceeds to torment them. Mental health advocates have expressed outrage at the trailer’s violent stereotypes of mental illness and its potential to stigmatize conditions like dissociative identity disorder. A petition that requests actors from the film release a public service announcement about mental health has now gathered over 15,000 signatures.

Mental illness has long been a staple of American cinema. From hallucinations to depression to mania, the characteristics of mental disorders lend to storytelling, often far more than other medical conditions. With millions of viewers every year, movies have the power to shape public understanding of mental illness. As a mental health provider, I often grapple with these cinematic depictions—and the implications for my patients.

One Flew Over the Cuckoo’s Nest is a classic example. Based on a novel, this 1975 film tells the story of a man who feigns mental illness to get out of prison and joins a group of patients in a psychiatric facility.

In some regards, the film does well in portraying the shortcomings of mental health care during the era of institutionalization. Patients often lived under strict paternalism, locked up for months to years with little expectation of returning to normal life. Few effective psychiatric treatments existed at this time. The movie raised a key question: was the role of psychiatry to control those at the fringes of society?

Still, despite winning the Academy Award for Best Picture, the movie has left lasting stigma towards mental health care.

Decades later, we still haven’t shaken the images of wicked Nurse Ratched torturing innocent patients. Terrifying scenes of Jack Nicholson’s character receiving electroconvulsive therapy forever tarnished the procedure. While lobotomies had largely disappeared by the 1970s, his character is forced to undergo this surgery and turned into something of a zombie. A study published in 1983 of college students found those who watched the film developed considerably more negative attitudes towards people with mental health issues.

Around that time, an entire genre of horror films based on mental illness was emerging. After Hitchcock’s Psycho (1960) introduced us to the terrors of mentally unstable motel owners, the stereotype of violent mental patients exploded in movies. In Halloween (1978), Michael Myers escapes an asylum and goes on a killing spree. Since the 1980s, serial killer Freddy Krueger has terrified audiences of the Nightmare on Elm Street franchise—Krueger’s mother was said to have been gang-raped in a mental hospital, dubbing Freddy the “bastard son of a hundred maniacs.”

Today, we still see damaging stereotypes of mental illness all the time in mainstream cinema. Leonardo DiCaprio’s character investigates a frightening asylum for the “criminally insane” in Shutter Island (2010). In The Ward (2010), Amber Heard’s character and others struggle to escape straitjackets, electroconvulsive therapy, and the vengeance of a former patient. As we’ve seen, mental health advocates fear Shyamalan’s Split will soon join this group.

Research suggests the portrayal of mental illness in films is overwhelmingly negative—and may leave lasting impressions on audiences.  In a 2001 survey of community college students, more than 90 percent of respondents reported learning about mental illness from movies. A 2004 study found 85 percent of animated Disney films included references to mental illness, most often in a denigrating manner.

Fortunately, not all films perpetuate stereotypes against people with mental health conditions. Some help us better understand the experience of mental illness, fostering awareness and empathy towards those in need.

In 2001, A Beautiful Mind captivated the country with the biography of legendary mathematician John Nash. Nash, who was diagnosed with schizophrenia, won a Nobel Prize for his work in economics, and the film showed us how even the most influential leaders can grapple with mental illness. Many in the mental health community praised the film’s depiction of schizophrenia, calling it “compassionate” and “historic.”

Another movie that realistically portrays mental illness is Michael Clayton (2007). In the film, Tom Wilkinson plays a senior partner at a prestigious law firm who suffers from bipolar disorder. His opening monologue is an eerily accurate depiction of mania, reminding me of patients I’ve cared for. The film takes on issues like medication non-adherence and the legal framework of involuntary commitment.

Perhaps my favorite film that addresses mental illness is Take Shelter (2011). Michael Shannon plays a rural father with a family history of schizophrenia who slowly descends into madness. The film touches on key issues in mental health care, such as the difficulties in maintaining family life, stigma in the community, and limited access to providers.

Bob Carolla, a spokesman for the National Alliance on Mental Illness, summed the film up best: “Too often when a movie company contacts NAMI to say they have released a film about schizophrenia, I cringe. More often than not, the film involves stereotypes and violence. But Take Shelter isn’t one of those films.”

The medical community is recognizing the impact of movies on public attitudes towards mental illness. Psychiatry departments at Baylor, Drexel, and Harvard, among others, have founded movie clubs that examine mental health themes in cinema. Medical school faculty have promoted film viewings as a way of teaching doctors-in-training about topics in mental health.

In the meantime, mental illness seems to be playing a starring role in more and more movies. Whether it’s Silver Linings Playbook (2012) or Side Effects (2013), Touched With Fire (2015) or now Split (2016), filmmakers walk a fine line between entertainment and reality when their stories hinge on mental health issues. These portraits influence public attitudes towards illnesses shared by millions of Americans, shifting the landscape of mental health care in this country.

At a time when mental health needs have never been greater, yet people remain afraid to speak up, we could sure use a helping hand from Hollywood.