Games, Lee perceived, were also becoming far more immersive, with elements designed to “make the user stay as long as possible.” In 1998 the South Korean gaming company Nexon had invented the “free-to-play” business model, in which games are technically free but require constant cash infusions for the player to meaningfully progress. Since then, companies had been churning out games that enticed users to spend money in ways that seemed to resemble gambling. That explained something else Lee had noticed: the debt his patients were racking up.

By 2011, Lee was convinced that gaming addiction was real and diagnosable, and that it was hindering children’s academic performance and sleep. That same year, as national panic mounted, the government proposed the Shutdown Law, a curfew that would block access to online games for those under 16 between midnight and 6 a.m. In a government-commissioned study outlining the policy’s benefits, Lee argued that gaming addiction had inflicted “mass trauma” on the nation and was to blame for suicides and homicides. The law passed by a large majority and is still in effect today.

In 2002, an unemployed 24-year-old man died after playing for 86 hours straight. It was the world’s first reported case of death by gaming.

The following year, Lee joined forces with a newly minted lawmaker named Shin Eui-jin, who had put gaming addiction at the top of her agenda. A former child psychiatrist, Shin was preparing a so-called “addiction bill” that aimed to regulate what fellow lawmakers called the four evils of South Korean society: gambling, alcohol, drugs … and video games. Gaming addiction, Shin claimed, was responsible for schoolyard bullying and violent crime. At a 2014 parliamentary hearing, Lee told lawmakers that gaming might be “an even stronger addiction than drugs,” and when asked whether he would be open to removing it from the list of addictions, he said, “I’d sooner take out drugs.” (Lee now insists the comment was taken out of context: “What I meant was that we need a legal support system to prevent and treat a problem that’s far more prevalent than drug use.”)

But whereas the Shutdown Law had passed easily enough, Shin’s bill quickly became bogged down in controversy. While medical experts like Lee said gaming addiction was real, others claimed there was no conclusive evidence that video games were inherently addictive. Critics skewered the bill and said Lee’s comments were a witch hunt. When the legislation failed to pass, it seemed the debate had reached an impasse—until it was recently reignited by an unlikely source.

Is this really a public health crisis?

On May 25, 2019, in Geneva, Switzerland, members of the 72nd assembly of the World Health Organization unanimously voted to pass the 11th revision of the International Classification of Diseases, the WHO’s official catalogue of illnesses. Among the revisions is the addition of “gaming disorder,” defined as “a pattern of persistent or recurrent gaming behavior” accompanied by a loss of control and functional impairment. It is only the second globally recognized behavioral addiction; the first was gambling, which was approved in the last revision of the ICD in 1990.

ICD-11, which goes into effect in 2022, adds thousands of new codes to more accurately capture specific injuries and diseases, as well as correcting historical mistakes. Strokes, for example, will now be classified as a neurological problem rather than a circulatory one; “gender identity disorder” is now “gender incongruence” and is no longer classified as a mental disorder.

Adding gaming disorder to the official medical lexicon marks a significant shift. Despite the years of concern and study about the effects of video games, conclusive evidence of any links to addiction or violence has been hard to come by. For many, the idea that somebody can be clinically addicted to behaviors—rather than to substances like alcohol or opioids—remains controversial. Others think the definition of gaming addiction in particular is too woolly to be useful.

“We’ve had 30-plus years of research on gaming addiction and we’re not really anywhere closer to understanding what it is that we’re actually talking about,” behavioral researcher Pete Etchells recently told MIT Technology Review.

For people like Lee, the psychiatrist, the decision is a vindication. The grounding for the WHO’s decision came out of talks among an advisory group of mental health researchers that he had been invited to join in 2014. Reports from the group’s annual meetings, which were held from 2014 to 2017, noted “the wide-ranging perceived benefits of increased government prevention” in South Korea, as well as “significant developments” in prevention, treatment, and research.

Yet some have disputed the caliber of the South Korean work. According to a recent meta-study, 91 of the 614 papers on gaming addiction published internationally from 2013 to 2017 were from that country, making it the single largest contributor by volume. The study’s author, Yonsei University media studies professor Yoon Tae-jin, argues that many of those studies are overly broad, treating gaming as a single category and failing to distinguish specific games or genres. Most of the research, according to Yoon, suffers from a confirmatory approach: assuming that gaming addiction is real from the outset, rather than trying to prove it scientifically.