Mariah Carey has revealed that she has been battling bipolar disorder all her life.

In a new cover story for People, the multi-platinum-selling singer opens up about her struggle with the disorder.

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“I didn’t want to believe it,” Carey says of her 2001 diagnosis after being hospitalized for a mental and physical breakdown.

The 48-year-old also reveals that she didn’t seek treatment until relatively recently after enduring “the hardest couple of years I’ve been through.

“Until recently I lived in denial and isolation and in constant fear someone would expose me,” she explains. “It was too heavy a burden to carry and I simply couldn’t do that anymore. I sought and received treatment, I put positive people around me and I got back to doing what I love — writing songs and making music.

“I’m actually taking medication that seems to be pretty good. It’s not making me feel too tired or sluggish or anything like that. Finding the proper balance is what is most important,” Carey says.

The singer adds that she is also now in therapy. Her specific condition, bipolar II disorder, is characterized by depression and hypomania, which is less severe than that of bipolar I disorder, and can cause sleeplessness, irritability, and hyperactivity.

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“For a long time I thought I had a severe sleep disorder,” Carey says, “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,” she admits. “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.”

On her decision to reveal her diagnosis publicly, Carey says, “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,” she adds. “It can be incredibly isolating. It does not have to define you and I refuse to allow it to define me or control me.”

For mental health support, contact the Depression and Bipolar Support Alliance at dbsalliance.org.