There have been scientific studies that show that addictions frequently run in families. Now there is certainly a possibility that one's environment - for example growing up with an alcoholic parent - can strongly influence one's behavior, but there have also been studies of twins, separated at birth and raised by unrelated adoptive families, which show that identical twins (who share the same genetic material) are more likely to both develop addictions than fraternal twins who do not share identical genes. Furthermore, there have been studies which show that people who have suffered injuries to their frontal lobes, the areas of the brain that handle planning and impulse control, are at risk of developing addictions subsequent to their injuries.
I believe that addiction is a disease. There are people who have a genetic predisposition to addiction and environmental stresses could lead to the expression of those genes. We've seen it most obviously with adolescents experimenting with drugs. Some can walk away unharmed, while others are trapped by addiction. But it's not just drugs. People can become addicted to anything that stimulates the brain's reward system: food, entertainment, exercise, etc. After accepting that addiction is a disease, we now raise the question of how to treat the disease: opening up an entirely new debate.
Addiction should be treated like a disease because it is very harmful to the every day lives of some people. Similar to a mental illness, it can be a danger to others. People who have addictions will commit crimes in order to satisfy their addictions. I believe they can be considered a disease.
Addiction is a disease, as is diabetes, cancer, depression, and the list goes on. People with an addiction are not in their right mind. Be it drugs, alcohol or gambling, it takes over your life, just like a cancer. People with an addiction should be helped, not punished. Whomever started them on that addiction should be punished.
I do believe that we should consider addiction a disease. Much like a disease, addiction needs to be cured through appropriate help from outside sources like addiction counselors. Diseases also need to be cured through interventions, and since interventions can help those with addiction, I feel it is very much like a disease.
We as humans like to use denial as a means of making ourselves feel comfort about things we don't want to accept. Saying that addiction is a disease supports a victim complex and subscribes to the idea that we are not in control of our own actions. There is very little evidence to support the stance that addiction is a disease, the evidence put forth is paper thin at best. Neuroplasticity explains how our brains change with new thoughts and learning patterns, and it has been proven time and time again that people with addiction have the power to quit on their own. In most cases they do.
Brain chemical difference does not indicate a disease because you ARE your brain, you ARE your neurons, you ARE your brain chemicals. That's just the physical manifestation of how you think, feel and the results of your thoughts and how you engage your everyday life. You are responsible for it. An addiction is when something has a very strong positive emotional pull on you(which yes is expressed chemically in the brain as the brain reacting strongly with dopamine production when presented with the addiction). But we are not slaves to our emotions. A person can choose that because they are unhappy with where there life is at, unhappy with what their habit is doing to them that the displeasure, cravings, and boredom that results from cessation is worth it.