This week, singer Mariah Carey [VIDEO] revealed for the first time that she has been suffering from Bipolar Disorder since 2011 after she had a breakdown and was hospitalized.

More than 5 million Americans suffer from some form of mental illness. Here are just a few well-known celebrities who have a mental health condition that includes bipolar disorder.

Most of the celebrities have become advocates for mental health issues.

1. Demi Lovato

Demi Lovato [VIDEO] was diagnosed with bipolar disorder when she entered rehab three years ago.

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Before her diagnosis, she had struggled with bulimia, drug addiction, and cutting. The 25-year-old singer is now an advocate to help others affected by mental health conditions.

2. Dwayne 'The Rock' Johnson

To look at the successful actor, most people would think Dwayne "The Rock" Johnson was in perfect health. However, the former professional wrestler shared in an interview that he has suffered from severe cases of depression.

3. Russell Brand

Russell Brand has been transparent about his mental health condition. The 42-year-old actor admits he has been diagnosed with attention deficit hyperactivity disorder (ADHD) and bipolar disorder. He has overcome bulimia, pornography addiction, drugs, alcohol, and a period of self-harming. He is now a sponsor to help others.

4. Catherine Zeta-Jones

Catherine Zeta-Jones has bipolar II disorder like what Mariah Carey just admitted that she has.

The wife of Michael Douglas has been public about being bipolar and has been an advocate so she can inspire people to seek treatment.

5. Mel Gibson

Actor and producer Mel Gibson shared in a 2008 documentary that he had bipolar disorder. Gibson made headlines for erratic and drunken behavior in the past. In recent years, he has been directing blockbuster movies and seems to have the condition under control.

6. Mike Tyson

Former champion boxer Mike Tyson has been diagnosed with bipolar disorder. For many years, he struggled with drug and alcohol addiction. He has been sober for a number of years and manages his mental health condition.

7. Ginger Zee

Ginger Zee, the "Good Morning America" chief meteorologist, opened up on the ABC morning talk show about her battle with depression and her suicide attempt when she was 21 years old. She recently published a memoir about her struggle with mental health issues.

8. Gabourey Sidibe

Actress Gabourey Sidibe says she has battled depression and panic attacks over many years until she decided to see a therapist and a doctor.

She takes an antidepressant to manger her depression. She advises others to do the same if they become depressed.

9. Elizabeth Vargas

ABC News anchor Elizabeth Vargas shared on "20/20" how she struggled with anxiety and panic attacks that led her to drink excessively. Today, she is sober and works with children who have mental health and learning disorders.

10. Other celebrities

There are many other celebrities who have voiced that they take medication for depression, bipolar disorder or some other form of mental health issues. The list included Bella Hadid, Kendall Jenner, Emma Stone, Lady Gaga, Chris Brown, and Jean-Claude Van Damme. When you see these people, it is hard to tell that they are dealing with mental health issues like millions of other people.