Imagine confining yourself to your bedroom every moment of your waking life.
You don't interact with the outside world - neither for school and work, nor to socialise on weekends.
Your life is pretty much centred around eating, sleeping, and partaking only in indoor solo activities like reading, watching TV, surfing the internet. How long could you handle this lifestyle before it drove you insane?
For a lot of people in Japan, that time period is indefinite. It's a huge social problem in the country, and it's becoming an economic concern too.
A survey released by the Japanese government this month found that 541,000 young people aged between 15 and 39 have completely disengaged from the outside world.
The real number is probably higher than that, given the reclusive nature of those experiencing it.
They refuse to engage in social contact and shut themselves in their homes - sometimes for several years at a time.
It's an ongoing phenomenon known as 'hikikomori', and over the past two decades it's emerged as one of the country's biggest social problems. Now, it's creating a generation referred to as Japan's "missing youth" or the "missing million".
WHAT IS 'HIKIKOMORI'?
The Health, Labor and Welfare Ministry defines 'hikikomori' as a phenomenon affecting people who have stayed at home for at least six months.
This means they don't go to school or work, they don't go out to interact with other people, and they barely - if ever - step outside of the walls of their homes.
They'll literally spend their waking hours trawling the internet, reading comics and eating in their bedrooms, without actually engaging with the real world.
Tamaki Saito, a Japanese psychologist and critic, described living with the condition as being "tormented in the mind".
"They want to go out in the world, they want to make friends or lovers, but they can't," he told the BBC.
They've also been described as apathetic, bored and nihilistic. They're seen as estranged from school and broader society, unable or unwilling to express their feelings and interests.
According to the government's survey on the subject, the main reasons for this were school truancy and difficulties adjusting to a working environment.
There is no treatment, although doctors believe it's caused by a mixture of psychological and societal factors.
WHO IS MAINLY AFFECTED BY HIKIKOMORI?
According to a review published in Research and Advances in Psychiatry last year, the typical 'hikikomori' patient is a 20-something male who's part of a family with a good socio-economic background.
Traditionally, the study explains, the first son or the only child is given the most social responsibility within the family; they're given the most pressure in an already hypercompetitive educational environment, and may exhibit a reduced ability to deal with the "dishonour" of low academic results or failure.
The researchers say the problem is predominantly based in Japan due to overwhelming cultural pressures there.
"Historically, Japan is a democracy in which society is presented as cohesive and protective for each citizen, and is based on two major criteria: inclusion and mainstreaming, which predominate over individuality expression," they write.
In other words, there's a lot of pressure to conform to social norms.
This same social pressure is often linked to Japan's notoriously high suicide rate - an endemic which mostly affects men. But the study also notes the suicide rate among 'hikikomoris' is relatively low.
The study says bullying plays a key part in the hikikomori phenomenon.
"Among the main causes of school withdrawal, ijime has to be mentioned," the study says, referring to bullying in Japan.
"Ijime is in most cases a form of psychological intimidation perpetrated by classmates or other peers to mentally weaker, or just "different" victims: name calling, teasing, and even extreme forms of social isolation are commonly acted."
But the problem isn't just limited to Japan. The researchers say the "social reclusion" phenomenon occurs across the globe, even within Australia.
But each different country frames the condition differently in according with its context.
In South Korea, for example, it's associated with the country's increasing problem with internet addiction, rather than conformity pressure.
A SOLUTION TO THE PROBLEM?
In an effort to help combat the problem, Japanese companies have begun developing virtual education facilities.
A virtual high school is effectively a digital classroom where almost every facet of learning is done online.
Students can attend commemoration ceremonies and lectures using virtual reality headsets, while their teacher or headmaster speaks from hundreds of kilometres away.
They can even get a 360-degree augmented reality tour of the campus.
Like an advanced form of Open University program, lessons are streamed to students via a smartphone app.
Students watch the lessons and take tests after each one, and submit reports and test results by sending photos of their work to their teachers.
A representative of The N High School, a fully-accredited school in Japan, said 73 of its 1482 freshmen attended via virtual reality, with their physical campuses over 1400km away.
N High School's founding principal Hirokazu Okuhira told the Japan Times it was about challenging the conventional education system.
"Rather than teaching what they know, a teacher's role today should be to act as a co-ordinator who instructs students on how to search websites and compile information into something they can express by themselves," Okuhira said.
He said online schooling presented the additional advantage of giving students spare time to work on topics that interested them without confining them by timing and location.
"There is no particular reason to attend a fulltime school; people just never question that it's the right choice. They just assume it is.
"We no longer live in an era where graduating students (start work doing) exactly the same thing," Okuhira said.
"But people are still afraid to be different."