When Glenn Close was researching her role as Alex Forrest in 1987’s “Fatal Attraction,” no one told her that perhaps a mental illness would motivate her character to hurt herself and stalk her married lover’s family — not to mention boil his daughter’s pet rabbit.

“I talked to psychiatrists, and mental illness didn’t come up once!” Close, 71, told Moneyish, adding that if she were playing that part today, “I would talk about her differently. She clearly suffers from a mental disorder, and she is in need of help and empathy.”

The lack of compassion and frank discussion about mental issues is a problem offscreen, as well. Although one in four adults (61.5 million Americans) experiences mental illness in a given year, more than half of these mental, behavioral or emotional disorders go untreated due to stigma, embarrassment and poverty. Untreated mental illnesses in the U.S. cost more than $100 billion a year in lost productivity, according to the National Alliance on Mental Illness (NAMI). And this can lead to a downward spiral of worsening health conditions; substance abuse to self-medicate; unemployment; homelessness; incarceration and suicide. Most suicides (90%) are directly attributable to untreated mental illness, Psychology Today reports.

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That’s why the “Damages” star, who was diagnosed with depression herself in 2008, has devoted the past several years to sparking conversation about mental illness. Close co-founded Bring Change to Mind in 2010 to fight the stigma and discrimination surrounding mental illness. And she’s joining fellow activists Logic, Brandon Marshall and the Steven Schwartzberg Foundation this week in a series of “Who Can Relate?” mental health events at the University of Michigan, including a roundtable on Thursday and a concert with Logic (whose song “1-800-273-8255” is the number for the National Suicide Prevention Hotline) on Friday.

“The worst thing that a human can endure is to be so marginalized, to be left out, to not have connection … and those with mental illness are the people that fall through the cracks,” said Close. “And stigma is the reason. It’s OK to talk about mental illness, and I like to. And I really want to have a country where people understand that this is just an illness, and people can recover from it — but we need funding to make that happen.”

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She credits her depression, which she treats with a low dose of antidepressant, and her family’s mental health history (her sister Jessie has bipolar disorder, and her nephew Calen lives with schizoaffective disorder) with making her “much more empathetic and tolerant to what people deal with.”

For example, she said she used to notice many people with mental health issues would have a “kind of scary look in their eyes,” but her nephew told her that he wears the same expression because he is the one who is actually terrified. “That was a huge revelation for me,” she said. “Someone living with a mental illness is really saying, ‘I’m terrified of you, and I’m trying to figure out how to negotiate life.’”

And most of the stigma around mental illness stems from fear; people assume someone with a mental illness is unstable, violent or dangerous, the Mayo Clinic reports, or the person with a diagnosis judges his or herself that way. A 2010 study found that 35% of adolescents with mental health problems described teachers and school staff treating them with fear, dislike, avoidance and underestimation of their abilities, while 62% of these affected teens lost friends and felt social rejection from their peers.

More than half of workers (58%) in a recent survey on mental health revealed they weren’t comfortable telling their boss if they were diagnosed with a mental health issue, and just 20% believed their manager would be supportive.

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And the complex connection between mental health issues and mass shootings has made the conversation even more weighted today. “I think people who perpetrate these terrible tragedies have fallen through the cracks in a tragic way,” said Close. “And if we were more vigilant, if we were more conversant about different types of behavior, if we cared enough to not just cut people out or off, but to persevere to a point where we know they are getting help … that has to be all of our responsibility, with friends, with family, with whoever is in your circle. You can’t ignore what other people are struggling with, because we’re all connected.”

So how do you support friends, family or colleagues with mental illness? The exact same way you should support them through any other illness, Close said.

“If I say, ‘My mom had cancer,’ you would go, ‘That’s terrible.’ So if I say, ‘My mom has bipolar disorder,’ you should react the same way: ‘I’m so sorry. How is she doing?’” said Close. “[My sister] Jessie said something that really was incredibly moving: ‘If I’d had cancer and was in the hospital, I would get flowers from all of my friends. But when you’re in the hospital with mental illness, nobody sends you anything.’ If you want to know how to make a friend who is dealing with these issues feel loved and accepted, send them flowers. Send a card. Just acknowledge what they’re going through. Say ‘You are a brave person. I’m proud of you.’”

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Harris Schwartzberg, the mastermind behind the University of Michigan’s mental health campaign, told Moneyish, “We’re trying to make people feel comfortable about talking about mental health. We’re doing that by filling a venue with people ‘Who Can Relate’” — including Close and Marshall, who are “mental health warriors” who “understand the seriousness of stigma and getting help.”

And Close believes it’s the students who will make lasting change. “I think us Baby Boomers majorly messed things up. Right now our culture is one where it’s ‘bigger, better’ all of the time, and that is bound to leave people behind,” she said. “College kids are gonna make the change — it was colleges and the kids that were letting their voices be heard down in Washington [at the March for Our Lives] this past week. And I’m sure we are going to hear more this weekend at UM. They feel strongly about things, and they know the kind of world they want to live in.”