Although Lowell’s manic depression was a great burden for him and his family, the exploration of mental illness in his verse led to some of his most important poetry, particularly as it manifested itself in Life Studies. When he was fifty, Lowell began taking lithium to treat his mental illness.
The worst thing about this is that this is not even worth stealing. It is boilerplate encyclopedia crap writing. I've never called poetry "important" in my entire life. What a disgusting case.