On July 26, 2000 the American Academy of Pediatrics, the American Medical Association, the American Psychological Association, the American Academy of Family Physicians, and the American Academy of Child and Adolescent Psychiatry stated that "prolonged viewing of media violence can lead to emotional desensitization toward violence in real life."  However, scholars have since analyzed several statements in this release, both about the number of studies conducted, and a comparison with medical effects, and found many errors (Block & Crain, 2007; Freedman, 2002).
In any case, there is nonetheless a good deal of evidence to indicate that modafinil is producing at least a portion of its wakefulness-promoting effects by acting as a DRI, or at least via activation of the dopaminergic system. In support of modafinil acting as a dopaminergic agent, its wakefulness-promoting effects are abolished in DAT knockout mice (although it is important to note that DAT knockout mice show D 1 and D 2 receptor and norepinephrine compensatory abnormalities, which might confound this finding), reduced by both D 1 and D 2 receptor antagonists (although conflicting reports exist),  and completely blocked by simultaneous inactivation of both D 1 and D 2 receptors.  In accordance, modafinil shows full stimulus generalization to other DAT inhibitors including cocaine, methylphenidate, and vanoxerine, and discrimination is blocked by administration of both ecopipam (SCH-39166), a D 1 receptor antagonist, and haloperidol , a D 2 receptor antagonist.  Partial substitution was seen with the DRA dextroamphetamine and the D 2 receptor agonist PNU-91356A , as well as with nicotine (which indirectly elevates dopamine levels through activation of nicotinic acetylcholine receptors ). 
percent of people found it difficult to get away from the Internet for about a number of days at a time, based on the statistic given by Stanford University. An interesting fact is that males are more likely to addict to the Internet, based on a research from the University of Lowa  . Not only being lured by these above factors, many students and teenagers come to the Internet as a way to hide from the real world. The pressure from parents’ expectation, from studying or even bullying scares them severely. They feel more comfortable and safer when living in a fiction world created on the Internet. The dangerous problem of internet addiction is not only about their life tendency but also their health. A study published on March 12, 2010, has shown a positive relationship between the use of the Internet and depression  . Specifically, people who are addicted to the Internet will be more likely to get depressed than normal people. According to Hilarie Cash, an American psychotherapist recommended that 8-10% of American teenagers get addicted to the Internet. This number means that approximately 2 million teenagers become depend on this system around the United States alone. It is a true alarm for people to recognize these negative effects of Internet on students and teenagers. If you want to know more about depression, a negative impact of Internet, click at Consequences of Depression