One study titled "Microstructure Abnormalities in Adolescents with Internet Addiction Disorder" from PLoS One concluded that adolescents with Internet Addiction Disorder:
Had multiple structural changes in the brain. The gray matter atrophy and white matter FA changes of some brain regions were significantly correlated with the duration of internet addiction. These results may be interpreted, at least partially, as the functional impairment of cognitive control in IAD. The prefrontal cortex abnormalities were consistent with previous substance abuse studies, hence we suggested that there may exist partially overlapping mechanisms in IAD and substance use. We hoped that our results will enhance our understanding of IAD and aid in improving the diagnosis and prevention of IAD.
The following infographic also reports that individuals with IAD can experience 10% to 20% surface area brain shrinkage similar to damage found in cocaine and alcohol addicts.
According to this source there are five warning signs that indicate that someone might be afflicted by IAD. They include the deterioration of social, work and home life, feelings of anger, restlessness or depression when not online and an increase in happiness while interfacing, and lying about the amount of time that you spend on the internet.
Coupons.org put out the following infographic:
Has the internet become a drug?
Apparently it is so powerful that a sizable proportion of those surveyed said they were willing to give up vices like alcohol, coffee, and chocolate before they gave up the internet. But people still continue to eat junk food while surfing the net.
The fact remains that playing on the internet is a sedentary activity and does not lead to a healthy balanced lifestyle if carried out in excess.
A study titled "Associations of Leisure-Time Internet and Computer Use With Overweight and Obesity, Physical Activity and Sedentary Behaviors: Cross-Sectional Study" from the Journal of Medical Internet Research found that: "Adults with high leisure-time Internet and computer use were more likely to be overweight or obese even if they were highly active in their leisure time as compared to participants who did not use the Internet or computer."
Greek Sage and philosopher, Epictetus, says it best, "If one oversteps the bounds of moderation, the greatest pleasures cease to please."
If you or someone you know is suffering from IAD you can find help here.