Originally Posted by
tormentedmirror 
Is this true, or are there those who have thought they were alchoholics, who may have discovered at some point that they are able to drink responsibly?
If an individual has been "deemed" an alcoholic, than yes, always an alcoholic.
To quote the Big Book:
"The idea that somehow, someday he will control and enjoy his drinking is the great obsession of every abnormal drinker. The persistence of this illusion is astonishing. Many pursue it into the gates of insanity or death."
The book also tells a story of a man who quit drinking to start a business. He knew in order to be successful, he had to fully focus on the endeavor so he quit drinking.
He retired after running a successful business for a number of years (25?) and then began drinking again. His drinking started to quickly take over his life. Within 4 years and after several hospital stays related to alcohol, he passed away.