I would bet at least another third are brimming with resentment because of the third that is cheating. This is unfortunately one more reason that so many bright students become bitter and cynical.
When it is stated that internet addiction has similar symptoms to serious addictions to powerful drugs, what comes most quickly to mind are drug addiction symptoms such as potentially lethal tremors, loss of normal bodily functions, irreversible organ damage, sharply increased cancer risks, heart disease, serious criminality, violence, and toxic overdoses. These are real and not unusual symptoms of addictions to drugs like alcohol, nicotine, amphetamines, heroine, cocaine, and prescription meds. I think it is a big overstatement to observe symptoms of forming a habit, which could be found alongside anything people do with regularity, and conflate it with the enormous health risks of drugs that account for a significant portion of human mortality. Aside from fairly isolated incidents of internet related deaths and cellphone car accidents, media is nearly the safest method people have invented to aimlessly fixate on something. I would even go so far as to be suspicious of what seems like a recent trend in concern over "internet addiction". It seems like a budding seed of justification planted to undermine the broad channels of communication and information many old media empires and governments would like to restrict, if only there were a good reason. This ridiculous reasoning certainly capitalizes off of the anxieties of an older generation that is confused and frightened by the immense change in media and the perspective from which such media functions.