Mariah Carey reveals she has Bipolar Disorder

HOUSTON -- Singer Mariah Carey is opening up about her 17-year battle with bipolar disorder.

"Bipolar disorder is a mood disorder and there are different kinds of mood disorders this one is where some individuals have periods of time where they have maniac episodes, and they have other periods of time where they are really depressed and that may last from weeks to months,” said Dr. George Santos.

The Multi-Grammy winner was diagnosed in 2001 after being hospitalized for a physical and mental breakdown, but says she didn't want to believe it. In her interview with People Magazine, Carey says, "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.”

Carey is not alone; This is a very common disorder.

"Four point five percent (4.5%) of the population in their lifetime might have a bipolar disorder any given year. The peak age of onset is in the mid 20's, it's evenly distributed between men and women,” said Santos.

If your parents carry the gene, you are more likely to have the disorder.

"There is a higher risk of bipolar disorder if you have a parent that has bipolar disorder. It's an even higher risk if you have two parents that have bipolar disorder. It's not absolute, but you are more likely to have bipolar disorder when you've had parents who had similar conditions,” Santos added.

Carey is now in therapy and taking medication for bipolar two disorder, which involves periods of depression. She hopes coming forward can help other people who have bipolar disorder.

"When someone comes forward and is public and you see that bipolar disorder or depression is something that people can live with treat and be very successful that is very helpful,” said Santos.