The Internet has become an integral part of many people's work and personal lives. The number of people online daily has nearly doubled over the past decade, according to research conducted by the Pew Internet and American Life Project. While internet addiction as a specific disorder was being debated for inclusion in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders as of 2010, treatment centers already exist throughout the U.S. and abroad, including China, Taiwan and Korea.
Internet overuse can lead to sedentary lifestyles, weight gain and a decline in physical fitness. Other symptoms can include carpal tunnel syndrome, dry eyes, migraine headaches, a decline in personal hygiene and back aches, according to Maressa Hecht, founder of Computer Addiction Services and a member of the Harvard Medical School.
Depression has also been linked to Internet overuse by researchers at the Institute of Psychological Sciences in Leeds, UK. Researchers found that study participants who exhibited signs of Internet overuse engaged disproportionately than the normal population in sites devoted to pornography, gaming, social networking and chat rooms. They theorized that Internet addicts' use of these sites as replacements for real-life socializing was resulting in depression. However, there is debate as to whether depression results from, or is a cause, or internet overuse. A study published in the "Archives of Pediatrics and Adolescent Medicine" found depression, as well as ADHD and social phobia, to increase the chances of excessive Internet use in adolescents.
Evidence also suggests that internet overuse can contribute to sleep disturbances. Studies of Chinese and American children, published in the "Journal of Sleep" and the "Journal of the American Academy of Pediatrics," found that computer use among adolescents was associated with later bed times, later waking times, less restful sleep and an overall decrease in sleep. The use of computers before bedtime has also raised concerns among sleep experts, including Phyllis Zee, a neuroscience professor at Northwestern University, that the light from screens is affecting circadian rhythms and possibly contributing to insomnia.