Isn’t it possible that someone could have a personality disorder or substance abuse problem AND a lousy character independent of that? Sometimes we tend to attribute everything unsavory or unappealing about a person to the thing which has been given a culturally defined, usually negative, label. All that is undesirable about someone is considered a by-product of their condition. If only they’d get help, we say.
But not every alcoholic who quits drinking becomes a delightful human being. And medication and therapy won’t instill a virtuous character in someone with a mental illness or other disorder if it was absent in the first place. I just think this gets overlooked.