Demi Lovato leaned into the microphone. "I tried to talk to my piano," she sang softly, stopping as she broke into tears.

It was her first performance since she suffered a drug overdose in 2018. The audience — gathered in Los Angeles' Staples Center in January for the Grammy Awards — applauded as Lovato took a deep breath and restarted "Anyone," the intensely personal ballad she wrote just days before the overdose nearly took her life. Lovato's tears returned when she finished the song.

There was no need for her to explain the emotions behind that moment. The singer has talked for years about her battles with bipolar disorder, substance abuse and eating disorders. That honesty made her a pioneer when it comes to celebrities opening up about mental health, said Katrina Gay, director of strategic partnerships for the National Alliance of Mental Illness (NAMI).

It's a space that largely didn't exist in 2012 when Lovato first shared that she had struggled for years with self-harm, anorexia, bulimia and drug and alcohol abuse, even as she courted increasing fame as one of the Disney Channel's marquee talents.

Nearly one in five U.S. adults live with a mental illness, according to a 2017 survey by the Substance Abuse and Mental Health Services Administration. Experts say talking openly about mental health can help break down stigmas that persist around depression, addiction, eating disorders and other issues.

Many sufferers are reluctant to do that — a reticence that, experts hope, celebrities can help overcome by talking about their own issues. But opening up about these serious, sometimes deadly, illnesses can come with its own set of challenges for people in the public eye.

Taylor Swift recently opened up about her history with disordered eating as part of her uncharacteristically candid Netflix documentary, "Miss Americana."

"I've learned over the years that it's not good for me to see pictures of myself every day," Swift says, noting that in the past, pictures she perceived as unflattering would sometimes lead her to "just stop eating."

"I thought I was supposed to feel like I was going to pass out after a show — or in the middle of it," Swift says as the film flashes to images of her during the world tour for "1989" — an unspoken emphasis on a frame she now says was never meant to be that thin. The juxtaposition between footage of Swift now and photos of her from several years ago made the singer's story "so much more visceral and more emotional," director Lana Wilson told Glamour.

Dangers lurk

But those scenes veer into territory that can raise concerns for those who treat eating disorders.

"With eating disorders there's so much comparison that even if your intent is a good one — to show your story and how dangerous some of this was — inadvertently people may take that as a benchmark ... to measure themselves against," said psychologist Christine Peat, an assistant professor of psychiatry at the University of North Carolina at Chapel Hill.

Swift has acknowledged her own shortcomings in discussing that part of her life.

"I'm not as articulate as I should be about this topic because there are so many people who could talk about it in a better way," the singer told Variety following the film's premiere at the Sundance Film Festival. "But all I know is my own experience."

Swift's ability to share that experience reflects changing cultural attitudes. Less than two decades ago, Gay had trouble booking a celebrity for a NAMI event. She eventually landed Patty Duke, the Oscar-winning actress who became an outspoken mental health advocate following her 1987 diagnosis with bipolar disorder.

At the time, Duke told Gay that many of her colleagues were reluctant to discuss their experiences with mental illness because they feared professional fallout — including being denied roles — should they speak publicly about their mental health.

Gay cites the 2014 suicide of Robin Williams as a major turning point, in part because "so many different people related to him across demographics and age groups." The cultural shift has been so profound that even newcomers like goth-pop sensation Billie Eilish, who has said her rapid rise to superstardom led to severe depression, can be frank about their mental health.

Over the past few years, a diverse group of stars — including Bruce Springsteen, Brad Pitt, Ben Affleck, Chrissy Teigen, Justin Bieber, Dwayne Johnson, Big Sean and more — also have spoken openly about their experiences with issues ranging from substance abuse to anxiety and depression.