"If sharing her story helps one person, if it saves one life – it's comforting"
Credit: Marie-Dominique Verdier

The last time Doris Fuller saw her daughter Natalie was the night before she left for a business trip. The close mother and daughter had planned a fun evening together, just the two of them. They went out to dinner, where Doris says her daughter was her usual charismatic self, and Doris flew out early the next morning.

Ten days later, on March 14, Natalie was dead. She had thrown herself in front of a train in Baltimore just a couple weeks shy of her 29th birthday. It was the tragic end to an almost eight-year battle with psychosis and bipolar disorder.

“Her voices told her to hurt herself,” Fuller tells PEOPLE. “And this time, nobody was able to stop her.”

Fuller penned a moving tribute to her daughter in The Washington Post, and now she’s sharing her story with PEOPLE in the hopes of educating others about the misconceptions of mental illness.

Fuller and her daughter always had a special relationship, but their bond grew even closer in 2004 when they wrote the bestselling parenting book: Promise You Won’t Freak Out: A Teenager Tells Her Mother the Truth About Boys, Booze, Body Piercing, and Other Touchy Topics (and Mom Responds).

A few years later, Natalie went off to college, and her first symptoms of mental illness appeared. What ensued was the rollercoaster almost 10 million adult Americans who suffer from bipolar disorder face, until her final spiral down.

“It’s indescribable,” Fuller says of being a parent to someone with mental illness. “This is the child that you’ve given birth to and you’ve loved with your whole heart. She’s a piece of myself and she’s lost her mind. It’s just devastating.”

A Close Bond

As a little girl, Natalie was full of life and joy. Creative and original, she liked to express herself through clothes and makeup, dreaming of becoming a theater makeup artist.

“From about the age of three, she would choose her clothes every day, and she would choose the wildest combinations,” says Fuller, a 64-year-old communications expert who lives in Washington, D.C. “For proms, all the girls came to our house and she’d do everybody’s makeup, there’d be a line. She even did my makeup when we did public appearances for our book.”

When Natalie was just 16, she and her mother found unexpected fame with their successful parenting book. They toured the country together on a book tour.

“I think because we did this really grown up thing when she was still a teenager, she became my best friend and we shared life in a way I didn’t share with anybody else,” Fuller says.

A Young Woman’s Struggle

Natalie first showed symptoms of mental illness during winter break of her junior year of college during a family trip to Europe.

“She was just kind of high – giddy and giggly and talked too fast and too much – she was just not herself,” Fuller says. “We all thought it was just jet lag and coffee.”

It was exactly one year later when Natalie had her first psychotic break.

“All the sudden she was laughing and screaming and saying nonsensical things. We thought she was high. Her brother and I went through her room looking for drugs, which we couldn’t find. We disabled the battery on her car so she couldn’t drive and kept her inside waiting for her to calm down, and she never did,” Fuller says.

Over the next several years, Natalie went through a series of highs and lows, but found periods of stability when she was on medication. At the time of her death, Natalie was off her medication, something she frequently did.

“Natalie was very frank about admitting she had a mental illness, but she hated it,” Fuller says. “She periodically would go off meds because that was her way of shaking her fist at the universe and saying, ‘You’re wrong, there’s nothing wrong with me,’ and then things would always go south.”

The Bravest Person I Knew

Although Fuller wasn’t with her daughter at the time of her death, she believes that she was psychotic at the time and the voices told her to harm herself.

“She was the bravest person I ever knew, and her suicide didn’t change that. It was not a logical choice; she was psychotic when she did it. I’m sure she was told by the voices to do it, but she had been saying for a long time, ‘I don’t want to live a life of psychosis.’ Of course, if she stayed on her meds, we wouldn’t be having this conversation.”

Fuller says she and her daughter would have candid conversations about her struggle to deal with her mental illness.

“She would say, ‘Mom, it’s not worth staying alive if I have to be psychotic all the time.’ She wasn’t suicidal, but she was quite frank about the fact that if she had to be psychotic, it was just too horrible, she was too tortured. She didn’t want to be tortured.”

A Mother’s Grief

“When she was stable, Natalie used to say, ‘I feel so sorry for you, Mom. This is much worse for you than me because when I’m really sick like that I’m having fun, but you know what’s going on and it’s not fun for you,” Fuller says.

Fuller was very open about her daughter’s diagnosis from the very beginning, and both she and Natalie found comfort in the support they received from friends and family by keeping an open dialogue.

“We’re never going to end the stigma until we stop acting like it’s something to be stigmatized. It’s just another disease. We have to stop treating mental illness like a secret and treat it for what it is – it’s a disease and it’s treatable and people shouldn’t be afraid of something they didn’t choose. We all know the symptoms of a heart attack, but we don’t know what psychotic symptoms look like, so we need to be better educated as a society.”

Advocating for Change

Like so many people who don’t have anyone in their own family with mental illness, Fuller didn’t know where to turn when her daughter became sick.

Through her research, she stumbled upon the Treatment Advocacy Center, an Arlington, Virginia-based nonprofit dedicated to eliminating barriers to treatment for people with severe mental illness. Fuller is now the executive director for the organization – a job that made her daughter very proud.

“She always retained a sense of humor, and she used to say that the one good thing about her getting mental illness was that it put me to work saving other people with mental illness. She could always find the bright side of things,” she says.

Fuller plans to keep her daughter’s legacy alive through her work with TAC and continue to advocate for those who suffer from mental illness.

“The world feels very quiet without her. It just blows a hole that nothing else will ever fill,” she says. “If sharing her story helps one person, if it saves one life – it’s comforting.”

For more information on mental illness, go to the National Institute of Mental Health (NIMH).