What type of psychology do I need to study in college if I want to specialize in drug addiction problems?

SAP. Substance abuse professional is a course offered by department of transportation by various companies - here is a list which you can call get info from - http://www.Dot.Gov/odapc/testingpubs/sapexamsources_200602_alpha.Pdf.
It depends. On whether you want to do research or work with patients. Clinical psychology is the type of psychology that allows you to work with patients.
Substance Abuse. Why not get a general education in psychology first? This way, you will have a foundation for learning the specialties. You'll need more than college, too, like a doctoral degree. Then you can go on and specialize in drug addiction issues.
Clinical psychology. Clinical psychologists help people with addictions. In my opinion however, there is no such thing as someone with an alcohol or drug problem. People do, on the other hand, have emotional problems and they use drugs or alcohol to deal with them. Clinical psychologists deal with those kinds of emotional imbalances.