I was addicted to alcohol for many years, I then stopped drinking and started to use Cocaine and then eventually Heroin. I switch addictions but, I become addicted to all of them. I heard from people that they can, however I think they are in denial. Addiction is a disease, not the drug you use. I will forever have to abstain from all drugs, as I am an addict. I believe addicts that say that they can do one substance moderatly and was addicted to another, are only justfying the fact that they do not want to get clean...excluded methadone which is given to H addicts to come off H. I don't classify this in the same way.