In my opinion gambling is an addiction and not disease, because you cannot quit gambling and when your disease accedes it will not leave you till death. One you cannot leave and the other does not leave you. This is the difference between addiction and disease. Therefore I can say that gambling is an addiction because you cannot leave it until it destroys you.
It is actually a disease if we really want to look at it in the literal sense and in this case, I would say it is a disease of the brain and mind. Disease can be referred to as someone who is actually in a disorder, have specific symptoms that affects a specific location which in this case is the mind of the addict as well as the brain. As long as something is adversely affecting someone and the person is finding it hard to get rid of it, my brother, which is a disease and a very crazy one that can lead to someone's destruction actually if care is not taken. It all has to do with how ready you are actually, but to get rid of an addiction; you really need to be able to talk to your sense of reasoning.
Honestly, Symphonized was right because anything that causes disorders or malfunction in human system or habit can be called disease and don't believe it everyone who is addicted to gambling have the history of addiction in their family cause the gang or friend that ones mingle with will determine ones addiction.
Honestly, looking at the fact that something is hurting someone, they know it is hurting them and they still let it be anyway is a typical way of looking at a disease. Literally, disease according to the dictionary can actually be defined as a particular quality or disposition regarded as adversely affecting a person or group of people and in that case and with that definition, that obviously makes gambling addiction or whatever form of addiction a disease. I guess with such a definition, I do not think we should even be debating whether it is a disease or not.