Video Game Addiction: Mental Illness?

[Amadeus]

"Addiction is a dependence on a behavior or sub-stance that a person is powerless to stop. The term has been partially replaced by the word dependence for substance abuse. Addiction has been extended, however, to include mood-altering behaviors or activities. Some researchers speak of two types of addictions: substance addictions (for example, alcoholism, drug abuse, and smoking); and process addictions (for example, gambling, spending, shopping, eating, and sexual activity). There is a growing recognition that many addicts, such as polydrug abusers, are addicted to more than one sub-stance or process."

Which changes what exactly?