Hi, I am an alcoholic and had a thiamine deficiency when I first sobered up, which who knows how long it had been going on. But anyways, I was checked after being sober for about 3 months, and everything was back to normal.
Here is an article the does a good job explaining thiamine deficiency and alcoholism.
http://pubs.niaaa.nih.gov/publications/arh27-2/134-142.htm
Randy