When words are misused in conversational English, it is unfortunate but hardly catastrophic. Medical terminology, however, is designed to be more precise, and misapplication of labels can have more serious consequences. For that reason it is distressing that the term "disease" is being misapplied frequently of late to refer to maladies such as alcoholism, compulsive gambling, anorexia and the like.
Stedman's Medical Dictionary is quite specific regarding the meaning of this term, defining disease as ". . . an interruption or perversion of function of any of the organs, an acquired morbid change in any tissue of an organism, or throughout an organism, with characteristic symptoms caused by specific micro-organismal alterations."
Most doctors would be careful to refer to a condition such as epilepsy not as a disease but a disorder, yet many of these same doctors will yield to fashion in speaking of "the disease of alcoholism." Alcoholism (as differentiated from results of alcoholism, which can include certain bona fide diseases) simply does not fit the definition of disease. It is much more correctly classified as a "compulsive behavior," along with other forms of chronic substance abuse, and uncontrolled gambling, eating, shopping, etc.
Some may view this as an argument over semantics, and I will admit that it is, in part. I must also insist that there is nothing frivolous about semantics.
But this is also a matter of scientific category, and just as I would correct someone who insisted to me that a whale was a fish, I must also disagree with anyone who refers to a compulsive behavior as a "disease." A disease is something you have, and a behavior is something you do. That is a fundamental difference, and one the scientific community should keep in mind.