That means absolutely nothing in modern medical terminology. Drug and alcohol councelors tell people they have a disease, even though they're not doctors and have no legal right to diagnose or prognose a patient. They only get away with it because the word "disease" isn't used in modern medicine to refer to a specific medical condition. "Disease of the mind" is 19th century quack speak. Addiction is really a syndrome, a collection of symptoms, but if someone with a two year degree in counceling told you you have a syndrom, you can sue them for practicing medicine without a licence.