Johnny Manziel says he's been battling bipolar disorder and depression for years -- and had used alcohol as a way to "self-medicate" ... but claims he's sought professional help to work through it.
"I am taking medication for bipolar, and I am working to try to make sure I don’t fall back into any type of depression," Johnny told "Good Morning America" ... "because I know where that leads me and I know how slippery a slope that is for me."
Former NFL star @JManziel2 reflects on 'mistakes,' reveals bipolar diagnosis in an exclusive interview with @tjholmes.