They can't sleep, can't concentrate and are wracked by bouts of anxiety or depression, and like anyone with a destructive bad habit, China's increasing number of Internet addicts need help, and need it fast.
The world's most populous country also has the world's largest Internet population, with 298 million users at the end of 2008 — an increase of nearly 42 percent from the previous year, according to the China Internet Network Information Center.
Problems caused by Internet over-indulgence are also on the rise, especially among the young, who comprise the majority of Chinese "netizens."
Many Chinese youth are single children who bear the heavy expectations of parents alone. Internet cafes offer an escape route, and some find it hard to leave, leading to overuse.
About an hour's drive from Beijing lies China's largest center for weaning them off-line, the Beijing Taoran Internet Addiction Treatment Center, which recently had to move 60 patients to a new facility as its old buildings can no longer house new addicts arriving from all over the country.
Treatment consists of medical and psychological therapy, and doesn't come cheap: each patient pays about $1,500 a month and if the results are not satisfying, they extend their stay for a second or even a third month.
A large number of Internet addicts are also referred to psychiatric hospitals where they are treated for various conditions including obsessive compulsive disorder.
Cracking under criticism
Chen Kehan, one of the doctors at the facility, said new patients are becoming less and less sociable — and thus more difficult to help. Some appear to have lost many of the social skills needed to function outside the virtual world.
"In the past year, there have been a lot more people calling or writing for information about our center. The condition of patients we take in has also become more serious than in previous years," she said.
The center is the brainchild of Tao Ran, a former doctor at the Beijing Military Hospital who spent several years in Canada studying addictions.
Tao then returned to Beijing, hoping to change attitudes in his home country, where Internet addiction is not formally considered a mental health disorder.
"There are more than 200 organizations offering treatment for Internet addiction in China now. If it weren't for the fast increase in the number of these hospitals, we would have many more people coming here for help," he said.
Parents are also encouraged to take part in the therapy, as Tao said they are often to blame for their children's addiction because they subject them to too much criticism.
To help prevent patients falling back into bad habits under parental pressure, fathers and mothers are required to sit in a classroom to be "scolded" by therapists. Sometimes their children are invited to attend and share their feelings.
Also for therapy, patients are required to arrange toy figurines in a sandpit in a scene of their choice. Many patients create violent battle scenes when they first arrive, but with treatment, these often turn more peaceful and orderly.
Teenager Cheng Jiawei has spent two and a half months at the center, and is due to be released soon. Her family sent her to the center when she started spending about 15 hours online every day after she failed to get into a school or find a job.
"When I played video games, I believed that I was a character in the games. I made friends playing video games that I couldn't make in real life," Cheng said.
Her final exercise involved arranging the figurines. The result? A house, a few pigs and several unnatural looking people.