It sounds like an interesting enough premise for a story: a young Japanese man is stifled by the pressure to excel in school, but scared to do noticeably better than his peers; he suffers from alienation amongst his friends, but he’s unequipped emotionally to talk about it with his family. One day, he just shuts himself in his room and stays there.

It’s the premise for the anime series Welcome to the NHK, which came out on DVD in the US in October, but the phenomenon is real. According to the New York Times, about a million Japanese people – mostly young men – are thought to suffer from hikikomori, a condition wherein the person holes up in their room and rarely or never comes out for years, or sometimes decades.

While plenty of people in other industrialized countries suffer from social anxiety and agoraphobia, according to the BBC, hikikomori is specific to Japan, probably for a number of reasons, not least of which is that parents will allow it. They’ll even bring their hikikomori (the word describes both the condition and the sufferer) three meals a day. In the States, your child’s room is still your property because it’s in your house, but that mentality doesn’t really exist in Japan. A young man (or, in rare cases, woman) has the autonomy to refuse his parents entry into his space, and to stay there in lieu of going to school, studying for the intense litany of standardized tests that determine an individual’s future in Japan, and engaging in face-to-face relationships. Parents don’t want to draw attention to the fact that there’s an anomaly in their family because conformity is a virtue in Japanese culture, so they’re frequently reluctant to seek outside help. The intense pressure to fit in is often a major component of what makes someone become a hikikomori in the first place, and the cycle can result in a guy never leaving his room for years.

NHK, based on a manga that debuted in Japan in 2002, appears to be among the first anime series to focus on the syndrome and call it by name, but hikikomori have been references in various books and films in Japan since the early 2000’s. The main character in the anime series Rozen Maiden is also a hikikomori.