Article continues below advertisementLady Gaga opened up about filming an Oscar-nominated film on lithium and the "really scary" challenges that followed."I did A Star Is Born on lithium," Gaga, 39, revealed in a cover interview with a news outlet published on Thursday, November 13.Although Gaga, whose real name is Stefani Joanne Angelina Germanotta, didn't disclose a diagnosis, lithium is "used to treat mania that is part of bipolar disorder (manic-depressive illness)," per the Mayo Clinic.