Here's one of the first results on Pubmed about gambling and withdrawal:
"Despite clinical reports of other withdrawal-like symptoms, the DSM-IV considers only restlessness/irritability as a withdrawal-like criterion comprising pathological gambling disorder (PGD). We explored whether this criterion should be broadened to include other gambling withdrawal-like symptoms.Community-recruited adult gamblers (n = 312) participated in telephone interviews about gambling and related behaviors as a part of a larger psychometric study. Frequency and chi-square analyses described the association of gambling withdrawal-like symptoms by gambling disorder status. Multinomial forward selection logistic regression obtained a multivariate model describing the simultaneous relationship between these symptoms and gambling disorder status.
One-quarter of the sample experienced the DSM-IV PGD criterion of restlessness/irritability. However, 41% experienced additional gambling withdrawal-like symptoms when attempting to quit or control gambling. A model including restlessness/irritability and three additional non-DSM-IV withdrawal-like symptoms (i.e. feelings of anger, guilt, and disappointment) is a stronger model of gambling disorder (chi(2) = 217.488; df = 8, p < 0.0001; R(2) = 0.5428; p < 0.0001) than restlessness/irritability alone (chi(2) = 151.278; df = 2, p < 0.0001; R(2) = 0.4133). The overlap of gambling withdrawal-like symptoms with substance use withdrawal (11%) and depressive symptoms (34%) failed to fully account for these associations with gambling disorder status.Future PGD conceptualization and potential criteria revisions for DSM-V may warrant a broader inclusion of gambling withdrawal-like symptoms."
Cunningham-Williams, et al. 2009
After being crit by that text wall the TL;DR version is that people experience withdrawal from attempting/quitting gambling, and they are making the argument more criteria should be included.
Yes people over use the term, "i'm addicted to them," but people can become legitimately addicted to things like this, It has to do the the reward-schedule and the response your brain has to them. For example, the most addictive reward-schedule is a completely random one (surprise surprise like gambling). Your brain does release it's on chemicals in response to these rewards and hence, you can become physically dependent on them - another example is people who are addicted to sex/masturbation.
Oh, and to the point about disease here are some of the definitions from a google search:
an impairment of health or a condition of abnormal functioning
A disease or medical condition is an abnormal condition of an organism that impairs bodily functions, associated with specific symptoms and signs. It may be caused by external factors, such as invading organisms, or it may be caused by internal dysfunctions, such as autoimmune diseases.
hmmm - by those definitions addiction would fall into the category of disease, because it certainly falls under the abnormal functioning, but hey, i'm sure you're better qualified to determine the definition, and whether addiction falls under it.