Too much time spent on the internet can damage a teenager's brain as much as taking alcohol or cocaine, researchers found.
Nerve fibres in the brains of teens addicted to the internet were less healthy than normal.
These nerves were in the white matter in the brain and spinal cord that helps the brain to communicate with the rest of the body.
Professor Lei Hao, of the Wuhan Institute of Physics and Mathematics of the Chinese Academy of Sciences, said last week that the study showed that too much internet use was related to brain damage.
Yet he said scientists still needed to measure how close the link was.
High-resolution brain images of the teens diagnosed with internet addiction disorder gave scientists clues as to where and how the damage took place.