A well-known psychiatrist with bipolar disorder, Kay Jamison, published a book titled "Touched with Fire: Manic-Depressive Illness and the Artistic Temperament". In her own words:
"The main purpose of this book is to make a literary, biographical, and scientific argument for a compelling association, not to say actual overlap, between two temperaments- the artistic and the manic-depressive- and their relationship to the rhythms and cycles, or temperament, of the natural world. The emphasis will be on understanding the relationship between moods and imagination, the nature of moods- their variety, their contrary and opposition qualities, their flux, their extremes (causing, in some individuals, occasional episodes of 'madness')- and the importance of moods in igniting thought, changing perceptions, creating chaos, forcing order upon that chaos, and enabling transformation." (5)
Some of the persons mentioned: Byron, Tennyson, Melville, William and Henry James, Schumann, Coleridge, van Gogh, Hemingway, Virginia Wolf. I think she presents a compelling argument that extreme fluctuations in mood, when coupled with an enforced rational thinking process results in more interesting creative output. Granted, their lives may still suck.
I don't know man, maybe you're right. Brando had a hard life. But if you watch the film from which that quote originates, "Listen to me Marlon", he backs it up with his experiences. Like, in one of the first films he did called "The Wild One" he plays this "electrifying" role as a macho dude on a motorcycle who also has feelings too. Brando knew at the time that was gonna make bank, because of all the shit in the news about Hell's Angels.