Internetaddiction is officially a mental disorder listed in the psychiatry Bible the DSM, and Asian countries a bit ahead of us in usage are taking it very seriously.
Internetaddiction, or formally, Internet Use Disorder (IUD), may soon be included as an actual mental health disorder, although the authors do say it still needs a lot of additional study.
These cases represent the dark side of addiction, certainly, but internet addicts with a milder version of the disorder might argue that their dependence is actually beneficial, since it lets them be more productive professionally.