Chances are you know someone who has been to rehab. That's how extensive the problem of substance abuse has become in the United States. Technically the term drug rehab can mean any of the various types and levels of treatment programs for substance abuse. It has, however, become synonymous with spending 30 days in a full time, residential treatment center. It's primary goal is to teach a person about the disease of addiction and what they will need to do in order to stay clean.