Mariah Carey just came out with a bombshell about her mental illness, revealing she’s been battling bipolar disorder.

“Until recently I lived in denial and isolation and in constant fear someone would expose me,” she said People. “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.”

The singer hopes her coming out will ease the stigma associated with mental illness. She suffers from bipolar II disorder, the symptoms of which include periods of both depression and hypomania, a type of mania that’s less severe than that associated with bipolar I disorder, but that can still cause insomnia, hyperactivity, irritability and feelings of elation. Periods of hypomania are typically shorter than manic periods, reports Page Six.

“For a long time I thought I had a severe sleep disorder,” she explained of her diagnosis. “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 continued. “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.”