More than half a million young people in Japan have shunned society and chosen to live isolated lives, according to a survey released by the government.

The phenomenon, called “hikikomori”, is defined by the Japanese Health, Labor and Welfare Ministry as people who have stayed in their home for six months or more without going to school, work or venturing out to socialise.

The survey found that 541,000 15 to 39-year-olds were living in isolation. The figure is actually lower than was estimated in the 2010 cabinet office survey, when 696,000 were thought to be suffering from hikikomori.

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However, those who do withdraw are doing so for longer, according to the study, as those who have shut themselves in their homes for at least seven years accounted for 35 per cent of the total. Another 29 per cent have lived as recluses for three to five years, The Japan Times reported.

There are more older recluses too – the number of those aged between 35 and 39 has doubled in six years, according to the survey.

Yet an accurate picture of who is suffering from hikikomori is difficult to determine given the reclusive nature of those suffering from it.

Having first emerged as a mass behaviour in the 1990s, the condition is not yet classified as an official disorder and there is no recommended treatment.

Doctors believe psychological and cultural influences combine to make young people feel they need to withdraw entirely.

In pictures: Japan celebrates Coming of Age Day Show all 7 1 /7 In pictures: Japan celebrates Coming of Age Day In pictures: Japan celebrates Coming of Age Day Japan Female tour guides dressed in traditional kimonos visit Tokyo's Meiji Shrine to attend a purification ceremony with a Shinto priest to celebrate Japan's Coming of Age Day. The ceremonies are held at local and prefectural offices, as well as after-parties amongst family and friends In pictures: Japan celebrates Coming of Age Day Japan Female tour guides dressed in traditional kimonos wash their mouths and hands at Tokyo's Meiji Shrine before attending a purification ceremony with a Shinto priest to celebrate Japan's Coming of Age Day In pictures: Japan celebrates Coming of Age Day Japan Since tour guides will be busy working on Japan's national holiday Coming of Age Day, the company held a ceremony In pictures: Japan celebrates Coming of Age Day Japan Female tour guides dressed in traditional kimonos are led by a colleague (R) as they visit Tokyo's Meiji Shrine to attend a purification ceremony with a Shinto priest to celebrate Japan's Coming of Age Day In pictures: Japan celebrates Coming of Age Day Japan Female tour guides dressed in traditional kimonos hang up 'ema', or votive tablets, with their written wishes at Tokyo's Meiji Shrine before attending a purification ceremony with a Shinto priest to celebrate Japan's Coming of Age Day In pictures: Japan celebrates Coming of Age Day Japan Coming of Age Day is a Japanese holiday held annually on the second Monday of January. It is held in order to congratulate and encourage all those who have reached the age of majority (20 years old) over the past year, and to help them realize that they have become adults In pictures: Japan celebrates Coming of Age Day Japan Young people turning 20 are officially recognised as adults in Japan. Coming of age ceremonies have been celebrated in Japan since at least 714 A.D. when a young prince donned new robes and a hairstyle to mark his passage into adulthood

The condition is far more common in men, who face huge pressures to succeed early in life, both at school and in their careers.

It is also more prevalent among the middle classes – those who isolate themselves are often well educated.

Sufferers of hikikomori often play video games or read comics at home, rather than interacting with others.

But psychologists say this is not caused by laziness.

Tamaki Saito, a Japanese psychologist has 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.