Mariah Carey has revealed in an exclusive interview with People that she was diagnosed years ago with bipolar disorder. "I didn't want to believe it," the 48-year-old Carey says about receiving the diagnosis back in 2001. She adds that she only recently sought treatment for the disorder after "the hardest couples of years I've been through." Adds Carey, "Until recently, I lived in denial and isolation and in constant fear someone would expose me. It was too heavy a burden to carry and I simply couldn’t do that anymore." She is now in therapy and on medication. "I’m just in a really good place right now, where I’m comfortable discussing my struggles with bipolar II disorder," she says. "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."