I will have to admit, I am no psychologist or drug & alcohol assessment professional of ANY sort.  But I don't think it takes a quantum physicist to know that the cheese has slid-off Charlie Sheen's cracker.  He has repeatedly taken drug tests to prove his sobriety, but was his last bender the one that broke his brain permanently?

From personal experience in dealing with people who have crossed over the fine line of sane to mental goo for the rest of their lives due to an over abundance of drug abuse, I seriously believe I might have some insight!

Those who experimented with LSD and other powerful drugs during the 60's & 70's and stopped while still able to function normally after their "high" was over, generally are able to carry out normal, productive lives.  Then there are those who didn't know when to stop and for the rest of their lives, they are past the point of no return.  This is where I think "Good Time Charlie" fits in.

I studied up a bit on Clinical Neuropychology on the website Brain Source and found information supporting my theory.

"one seeks to understand how the brain, through structure and neural networks, produces and controls behavior and mental processes, including emotions, personality, thinking, learning and remembering, problem solving, and consciousness. Neuropsychology seeks to gain knowledge about brain and behavior relationships through the study of both healthy and damaged brain systems."

After studying what Charlie's MAJOR malfunction is, I've come to realize it's rather sad actually.  Grant it, it's a outcome of his own doing.  It's still sad to see someone who was once such a great actor.  Now I guess Charlie joins Gary Busey in the "Droopy-Eyed Armless Children" category.  Bummer!