"The most important thing I can do for my children is give them ... a chance to live in a safe and secure home," Carey tells PEOPLE exclusively

By Jess Cagle
April 11, 2018 12:30 PM

After years of living “in denial,” Mariah Carey recently began treatment for bipolar disorder.

In this week’s PEOPLE cover story, she tells editor-in-chief Jess Cagle that she was diagnosed with the disease in 2001, but “I didn’t want to believe it.” But living with the disease and keeping it hidden “was too heavy a burden to carry and I simply couldn’t do that anymore.”

In a candid, surprising interview, she’s asked if being a mother to 6-year-old twins Monroe and Moroccan influenced her decision to get treatment. “No,” she says. “They’re everything to me. They’re never going to see me sitting around crying and being an emotional wreck in front of them. That’s just never going to happen.”

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Carey co-parents the twins with their father, ex-husband Nick Cannon, and she calls her relationship with him “very positive.”

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“My children are amazing,” says the superstar songwriter. “What could be more therapeutic than spending time with my kids and laughing and watching them enjoy childhood? The most important thing I can do for my children is give them what I didn’t really have, a chance to live in a safe and secure home surrounded by people who love and support them unconditionally.”

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Fresh Air Fund/WireImage

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Carey is now in therapy and taking medication for bipolar II disorder, which involves periods of depression as well as hypomania (less severe than the mania associated with bipolar I, but can still cause irritability, sleeplessness and hyperactivity).

“For a long time I thought I had a severe sleep disorder,” says Carey, who’s now back in the studio working on an album due later this year. “But it wasn’t normal insomnia and I wasn’t lying awake counting sheep. I was working and working and working. … I was irritable and in constant fear of letting people down. It turns out that I was experiencing a form of mania. Eventually I would just hit a wall. I guess my depressive episodes were characterized by having very low energy. I would feel so lonely and sad — even guilty that I wasn’t doing what I needed to be doing for my career.”

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Carey says she decided to speak publicly about her disease because “I’m just in a really good place right now, where I’m comfortable discussing my struggles with bipolar II disorder. I’m hopeful we can get to a place where the stigma is lifted from people going through anything alone. It can be incredibly isolating. It does not have to define you and I refuse to allow it to define me or control me.”

RELATED: Mariah Carey on How She’s Treating Her Bipolar Disorder: ‘I’m in a Good Place’

For more on Mariah Carey and her battle with bipolar disorder, dealing with fame and raising twins, pick up the latest issue of PEOPLE, on newsstands Friday. For mental health support, contact the Depression and Bipolar Support Alliance at dbsalliance.org.