Madness has always had a certain appeal in artists. it reveals core passions and a certain kind of truth. I always feel like it is exploitative, but like a car accident, I sometimes gawk with the crowd. July Garland on TV in her later career, the poet Sylvia Plath throughout her career, Oscar Levant on the Jack Parr show.
Some performers carry it off better and can access their anger and sorrows and still keep their balance, like Edith Piaf or Leonard Cohen.
I saw the Saturday Night Live show when O'Connor tore up the photo of the Pope. Being from Chicago, where I almost grew up Catholic with my friends, without being Catholic, I knew what a mistake that was. Nonetheless, may she rest in peace.