Does the Catholic Church consider alcoholism a sin such as adultery?
Yes, and no. The Catholic Church considers alcoholism as in drinking to excessive over a period of time a serious sin. Alcoholism, the condition where the body has become acclimated to a large consumption of alcohol would no longer be considered a serious sin, in and of itself, but the drinking that got you to that point would be considered a serious sin. To be considered a serious sin, free will must be involved, and a free decision. When you get to the point where there is little free will involved and little to no decision then you are looking at other sins perhaps, but no longer the original serious sin of just drinking to excess. Which is not to say that no sin is involved.