Mariah Carey reveals she has bipolar disorder

'I lived in denial and isolation and in constant fear someone would expose me'

Mariah Carey has revealed she is bipolar in a new interview.

The singer - one of the world's biggest selling in history - said she was first diagnosed with the disorder in 2001 and sought treatment after what she described as “the hardest couple of years [she's] been through.“

She told PEOPLE: “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. 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, who has amassed a total of 18 number one hits in the US and sold more than 200m records worldwide, said she continued to undergo therapy and take medication for bipolar II disorder, which causes periods of depression and hypomania.

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

“For a long time I thought I had a severe sleep disorder. 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 characterised 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.”

Carey said she felt comfortable talking about her struggles with bipolar as she was “in a really good place right now,” adding: “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.”

The singer-songwriter is back in the studio working on her 15th studio album following 2014's Me. I Am Mariah... The Elusive Chanteuse. It's expected to be released later this year.

For more information on bipolar and a support line number, visit bipolaruk.org