Note, from Mosher's summary in the Scientific American:
...the self-assessment test, created in 1998 by psychiatrist Kimberly Young of Saint Bonaventure University in New York State, is an unofficial standard among Internet addiction researchers, and it consists of eight yes-or-no questions designed to separate online addicts from those who can manage their Internet use. (Questions range from, "Do you use the Internet as a way of escaping from problems or of relieving an anxious mood?" to "Have you taken the risk of losing a significant relationship, job, educational or career opportunity because of the Internet?".Some further clips from that summary:
...another part of the new study on Internet addiction...zeroed in on white matter tissue deep in the brain which links together various regions. The scans showed increased white matter density in the right parahippocampal gyrus, a spot also tied to memory formation and retrieval. In the left posterior limb of the internal capsule, which is linked to cognitive and executive functions, white matter density dropped relative to the rest of the brain...The abnormality in white matter in the right parahippocampal gyrus may make it harder for Internet addicts to temporarily store and retrieve information, if a recent study is correct. Meanwhile, the white matter reduction in the left posterior limb could impair decision-making abilities—including those to trump the desire to stay online and return to the real world.