The 48-year-old singer told PEOPLE exclusively that she was diagnosed with the condition in 2001, after being hospitalised for a 'physical and mental breakdown.'
'I didn’t want to believe it,' she told the publication.
Carey reveals she only sought treatment after the 'hard couple of years' she's been through.
'Until recently I lived in denial and isolation and in constant fear someone would expose me,' Carey adds. '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.'
Carey tells the publication that despite living in denial, she is now seeking therapy and taking medication for bipolar II disorder.
'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,' she said.
Carey, who co-parents her 6-year-old twins Monroe and Moroccan with ex-husband Nick Cannon, says she decided to come forward 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.'