Hammer, thanks for the post.
Cazza, yes, alcohol can cause or exacerbate mental illness (see photo at link below). Alcohol eats the brain, and it can take the prefrontal cortex (responsible for good judgment and morals) much longer to recover; thus, it's reasonable to assume dry drunks may still have damaged brains/judgment.
http://2.bp.blogspot.com/_gZijMZCWPW...ohol-brain.jpg
Even as dry drunks, alcoholics can still be terribly negligent with children.