Yes that’s correct. Alcoholics have whats called a mental obsession with drinking caused by what is called the spiritual malady. So people basically drink because they like the affect. But it’s more pronounced with an alcoholic. When an alcoholic drinks it’s because they are restless, irritible and discontented - it’s like an emotional/spiritual problem. They want to feel good, spiritually. Basically searching for spirituality in their life. Drinking gives them an artifical spiritual experience and makes them feel “whole”. So when an alcoholic stops drinking, the mental obsession kicks in because emotionally/spiritually they feel terrible. Again, restless, irritable and discontented, and they need the ease and comfort that comes from drinking. So the mind tells them they can have a few, even though they know what can happen when they drink - and once an alcoholic starts drinking the alcoholic’s body is different then other people - a compulsion kicks in and they can’t stop drinking on many occasions. A heavy drinker can have this compulsion also when they start drinking as well but once they stop for any length of time, since they don’t have the mental obsession, with willpower they decide to not drink alcohol any more and are able to accomplish it.
This is what the program of AA says : “We hope we have made clear the distinction between the alcoholic and the non-alcoholic. If, when you honestly want to, you find you cannot quit entirely, or if when drinking, you have little control over the amount you take, you are probably alcoholic. If that be the case, you may be suffering from an illness which only a spiritual experience will conquer”. (from the Big Book of AA page 44).