Mariah Carey's Bipolar Disorder Diagnosis Sheds Light on Disease Subtypes

2015 BILLBOARD MUSIC AWARDS - Theatre - The "2015 Billboard Music Awards" broadcast airs live from Las Vegas at the MGM Grand Garden Arena on SUNDAY, MAY 17 (8:00-11:00 p.m., ET). on the ABC Television Network. (Photo by Ethan Miller/Getty Images via ABC) MARIAH CAREY

Pop culture’s spotlight has shone on legendary diva Mariah Carey for nearly three decades, but on Wednesday she revealed a secret she’s been keeping private for the past 17 years. In an interview with People, she spoke out about her long battle with bipolar disorder, a brain disorder for which she only recently started treatment.

In 2001, a critical point in her career, Carey had a mental and physical breakdown, which led to her receiving her diagnosis. However, she only recently started treatment because, as she told People, “I didn’t want to believe it.” In the interview, she explains that she thought she just had a “severe sleep disorder,” although she was also “irritable and in constant fear of letting people down.” Now, she has realized that “I was experiencing a form of mania,” which is one symptom of bipolar disorder. Carey is now being treated for bipolar II disorder, one of four subtypes of the complex disease.

According to the United States National Institute of Mental Health, all four subtypes of bipolar disorder, which is also known as manic-depressive illness, are characterized by “unusual shifts in mood, energy, activity levels, and the ability to carry out day-to-day tasks.” The shifts in mood give the disease its name: “These moods range from periods of extremely ‘up,’ elated, and energized behavior (known as manic episodes) to very sad, ‘down,’ or hopeless periods (known as depressive episodes),” the NIMH writes. Diagnosed with bipolar II disorder, Carey experiences “hypomanic episodes,” which are less severe manic periods.

Treatment usually includes a combination of medication and psychotherapy, which Carey is receiving. Medications usually include mood stabilizers, atypical antipsychotics, and antidepressants; therapy comes in a variety of forms, but all are meant to provide guidance and support for people with the lifelong illness. The causes of bipolar disorder are not clear, but recent research suggests that genetics is a big factor. In January, researchers showed in Biological Psychiatry that bipolar I and bipolar II subtypes are inherited in different familial patterns, suggesting a different genetic basis.

A person’s genetics alone, however, doesn’t determine their fate. Treatment can be very effective, just as it has been for Carey. “I’m just in a really good place right now, where I’m comfortable discussing my struggles with bipolar II disorder,” she said in her interview. “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.”

Carey’s willingness to speak out about her mental health echoes the recent efforts of celebrities like singer Zayn Malik and NBA stars DeMar DeRozan and Kevin Love to break down the sense of shame that leads people to forgo treatment. “It does not have to define you and I refuse to allow it to define me or control me,” she says.