http://en.wikipedia.org/wiki/Addiction#Varied_forms_of_addiction http://en.wikipedia.org/wiki/Addiction#Varied_forms_of_addic... Essentially the difference is

http://en.wikipedia.org/wiki/Addiction#Varied_forms_of_addiction http://en.wikipedia.org/wiki/Addiction#Varied_forms_of_addic... Essentially the difference is physical withdrawal symptoms versus mental ones (cravings, irritability, sleep issues, etc..). The line can definitely be fuzzy, and many addictions span both categories. In the case of pot versus physically addictive substances, such as alcohol or heroin, a heavy pot user forced into cold turkey withdrawal would not get the shakes, diarrhea, sweating, nausea, seizures, or death, that can happen with withdrawal of physically addictive substances.