Definition: "Addiction"

"Addiction is a primary, chronic disease of brain reward, motivation, memory and related circuitry. Dysfunction in these circuits leads to characteristic biological, psychological, social and spiritual manifestations. This is reflected in an individual pathologically pursuing reward and/or relief by substance use and other behaviors." - American Society of Addiction Medicine. 

The Disease Model of medicine says, there is a specific organ/body part affected...ie broken or dysfunctional.  This leads to specific symptoms.  It is able to be diagnosed, "this is the problem, these are the symptoms." 

Second, it has a prognosis if treated vs non-treated. "This is a treatment course, and the predictable outcome."

Dr. Kevin T. McCauley is a great resource for Addiction a Disease.

It's A Brain Disease.