It's a widely accepted opinion for sure, however I've yet to see any convincing science applied to it.
"The brains of "internet-addicted" teenagers may differ significantly from those of non-addicted teens, a small
study suggests.
Internet addiction, though not officially recognized by health-care authorities, has been defined in several studies as an
impulse-control disorder. It has been characterized by an overwhelming desire to stay online and impairs an individual’s ability to function on a day-to-day basis. Going offline leads the addicted individual to experience
withdrawal symptoms similar to those of alcohol and drugs.
The researchers used a technique called fractional anisotropy (FA) to measure the organization of the brain, which is greatly influenced by the number and location of white matter fibres. Those study participants who had displayed addiction symptoms showed lower FA values in a variety of regions of the brain, such as as the orbito-frontal white matter, corpus callosum, cingulum, inferior fronto-occipital fasciculus and corona radiation. Lower FA values indicate that the nerve fibres are not functioning properly.
...findings* indicate that internet addiction disorder has abnormal white matter integrity in brain regions involved in
emotional generation and processing, executive attention, decision making and cognitive control..."
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http://www.cbc.ca/news/health/story/2012/01/12/internet-addiction-study.html*
The study of 17 adolescents apparently addicted to the internet and 16 controls was conducted by Chinese researchers and published in the Wednesday issue of the journal PLOS One. :coughsamplesizecough:(comment: "OR, people with cognitive impairment are easily addicted to things such as the internet" <-- Troll, go away! There is no place for logic on the internet!