The compound — part boot camp, part rehab center — resembles programs around the world for troubled youths. Drill instructors drive young men through military-style obstacle courses, counselors lead group sessions, and there are even therapeutic workshops on pottery and drumming.

But these young people are not battling alcohol or drugs. Rather, they have severe cases of what many in this country believe is a new and potentially deadly addiction: cyberspace.

They come here, to the Jump Up Internet Rescue School, the first camp of its kind in South Korea and possibly the world, to be cured.

South Korea boasts of being the most wired nation on earth. In fact, perhaps no other country has so fully embraced the Internet. Ninety percent of homes connect to cheap, high-speed broadband, online gaming is a professional sport, and social life for the young revolves around the “PC bang,” dim Internet parlors that sit on practically every street corner.

But such ready access to the Web has come at a price as legions of obsessed users find that they cannot tear themselves away from their computer screens.

Compulsive Internet use has been identified as a mental health issue in other countries, including the United States. However, it may be a particularly acute problem in South Korea because of the country’s nearly universal Internet access.

It has become a national issue here in recent years, as users started dropping dead from exhaustion after playing online games for days on end. A growing number of students have skipped school to stay online, shockingly self-destructive behavior in this intensely competitive society.

Up to 30 percent of South Koreans under 18, or about 2.4 million people, are at risk of Internet addiction, said Ahn Dong-hyun, a child psychiatrist at Hanyang University in Seoul who just completed a three-year government-financed survey of the problem.

They spend at least two hours a day online, usually playing games or chatting. Of those, up to a quarter million probably show signs of actual addiction, like an inability to stop themselves from using computers, rising levels of tolerance that drive them to seek ever longer sessions online, and withdrawal symptoms like anger and craving when prevented from logging on.

To address the problem, the government has built a network of 140 Internet-addiction counseling centers, in addition to treatment programs at almost 100 hospitals and, most recently, the Internet Rescue camp, which started this summer. Researchers have developed a checklist for diagnosing the addiction and determining its severity, the K-Scale. (The K is for Korea.)

In September, South Korea held the first international symposium on Internet addiction.

“Korea has been most aggressive in embracing the Internet,” said Koh Young-sam, head of the government-run Internet Addiction Counseling Center. “Now we have to lead in dealing with its consequences.”

Though some health experts here and abroad question whether overuse of the Internet or computers in general is an addiction in the strict medical sense, many agree that obsessive computer use has become a growing problem in many countries.

Doctors in China and Taiwan have begun reporting similar disorders in their youth. In the United States, Dr. Jerald J. Block, a psychiatrist at Oregon Health and Science University, estimates that up to nine million Americans may be at risk for the disorder, which he calls pathological computer use. Only a handful of clinics in the United States specialize in treating it, he said.

“Korea is on the leading edge,” Dr. Block said. “They are ahead in defining and researching the problem, and recognize as a society that they have a major issue.”

The rescue camp, in a forested area about an hour south of Seoul, was created to treat the most severe cases. This year, the camp held its first two 12-day sessions, with 16 to 18 male participants each time. (South Korean researchers say an overwhelming majority of compulsive computer users are male.)

The camp is entirely paid for by the government, making it tuition-free. While it is too early to know whether the camp can wean youths from the Internet, it has been receiving four to five applications for each spot. To meet demand, camp administrators say they will double the number of sessions next year.

During a session, participants live at the camp, where they are denied computer use and allowed only one hour of cellphone calls a day, to prevent them from playing online games via the phone. They also follow a rigorous regimen of physical exercise and group activities, like horseback riding, aimed at building emotional connections to the real world and weakening those with the virtual one.

“It is most important to provide them experience of a lifestyle without the Internet,” said Lee Yun-hee, a counselor. “Young Koreans don’t know what this is like.”

Initially, the camp had problems with participants sneaking away to go online, even during a 10-minute break before lunch, Ms. Lee said. Now, the campers are under constant surveillance, including while asleep, and are kept busy with chores, like washing their clothes and cleaning their rooms.

One participant, Lee Chang-hoon, 15, began using the computer to pass the time while his parents were working and he was home alone. He said he quickly came to prefer the virtual world, where he seemed to enjoy more success and popularity than in the real one.

He spent 17 hours a day online, mostly looking at Japanese comics and playing a combat role-playing game called Sudden Attack. He played all night, and skipped school two or three times a week to catch up on sleep.

When his parents told him he had to go to school, he reacted violently. Desperate, his mother, Kim Soon-yeol, sent him to the camp.

“He didn’t seem to be able to control himself,” said Mrs. Kim, a hairdresser. “He used to be so passionate about his favorite subjects” at school. “Now, he gives up easily and gets even more absorbed in his games.”

Her son was reluctant at first to give up his pastime.

“I don’t have a problem,” Chang-hoon said in an interview three days after starting the camp. “Seventeen hours a day online is fine.” But later that day, he seemed to start changing his mind, if only slightly.

As a drill instructor barked orders, Chang-hoon and 17 other boys marched through a cold autumn rain to the obstacle course. Wet and shivering, Chang-hoon began climbing the first obstacle, a telephone pole with small metal rungs. At the top, he slowly stood up, legs quaking, arms outstretched for balance. Below, the other boys held a safety rope attached to a harness on his chest.

“Do you have anything to tell your mother?” the drill instructor shouted from below.

“No!” he yelled back.

“Tell your mother you love her!” ordered the instructor.

“I love you, my parents!” he replied.

“Then jump!” ordered the instructor. Chang-hoon squatted and leapt to a nearby trapeze, catching it in his hands.

“Fighting!” yelled the other boys, using the English word that in South Korea means the rough equivalent of “Don’t give up!”

After Chang-hoon descended, he said, “That was better than games!”

Was it thrilling enough to wean him from the Internet?

“I’m not thinking about games now, so maybe this will help,” he replied. “From now on, maybe I’ll just spend five hours a day online.”

NYTimes.com