I recently talked to a therapist at a rehab center and he said... that highly functioning alcoholics tend to be able to keep up appearances longer. While a construction worker who shows up after lunch smelling of beer will get kicked out on his backside pronto, lawyers can have two martini lunches and get away with it.
But, he said, that also usually means that when the high-functioning alcoholics finally get a crack in the foundation, they go downhill very fast. Because their disease has had that much longer to progress before the foundation starts crumbling.
My ex is a good example. He was brilliant and funny when we met. He always had a mean streak when he drank, and it got worse, but he was still fun to be around when he was sober.
And then there was less and less sober. And in five years he's gone from respected member of the community to being unemployed, on the verge of homelessness, and unable to follow a simple line of reasoning. He is paranoid and I'm the great satan.