The singer admits she was first diagnosed after a breakdown in 2001 but failed to seek treatment until recently. MARIAH Carey has said she is no longer living in “denial and isolation” after being treated for bipolar disorder. The singer has told celebrity magazine People that she “didn’t want to believe it” when she was diagnosed in 2001 after receiving hospital treatment for a physical and mental breakdown.  She said: “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.” The 48-year-old is now in therapy and taking medication for bipolar II, which involves periods…