Characterized by continuous or periodic.... impaired control over drinking
The inclusion of "periodic" is important. When I was drinking, I didn't know that periodic impaired control was a problem; I thought it was lack of will power.
For a long time, sometimes when I drank, I got plastered, and sometimes when I drank, I had a glass or two of wine. Sometimes, even, I didn't drink, even when others around me were partying it up. So the fact that sometimes I ended up in a blackout on the floor seemed to me that I didn't know how to drink properly - maybe I should have eaten before I drank; perhaps I should have stuck with beer; etc. Or, that I just didn't try hard enough to limit myself -- that I was simply a glutton.
It wasn't until the periods between being periodically out of control started to get closer and closer together, that I began to believe I had a problem with alcohol. Only periodically being out of control did not fit the definition I knew of alcoholism.
I'm glad that the AMA recognizes this. I can't say that if I knew earlier on that periodic lack of control could indicate alcholism that I would have gotten sober sooner, but I sure think it's a good thing for young folks to be taught that.