For me, anything that has mind-altering properties could be a possible addiction for me. In my 20's, I was addicted to Vicodin and had no problem getting them due to a back injury. After nearly overdosing on them, I was detoxed in the hospital and never went back to them. However, I did end up becoming an alcoholic about 15 years later.
I feel I am in danger of becoming addicted to anything that alters my state of mind and/or behavior, which is why nowadays I don't accept prescriptions for painkillers from my doctor unless I am in agony ... and even then, I make sure it is a very small script with no refills.
I don't know if it's the same for you, but it does seem to be a fairly common occurrence.