In the brains of adults, neural paths and connections are formed and completed their development in the general sense. Of course, we all can learn new things and can change these connections by making changes in our lives. But this process is extremely faster and easier in children.
Therefore it is easier for a child to become an internet addict rather than an adult. For the same reason, the changes caused by internet addiction on the brain is more significant in children and teenagers.
In addition to this, the natural impulse of children accelerates that plausible internet usage becoming an addiction. If you leave a child on her/his own, s/he may always want to eat candies or fast food. S/he does not think that excessive glucose consumption may cause to turn her/his stomach, to tooth decay or eating fast food all the time may cause nutrition disorders or obesity. Similarly, a child who enjoys the internet does not think that it may turn into an addiction or internet addiction can affect her/his social and academic life. That’s why the risk of internet addiction is greater in children and teenagers, and more dangerous for them as well.