Hikikomori, which means ‘pulling inwards’ in Japanese, is a condition in which those affected withdraw from society, often not leaving their homes for days on end. It was first identified in Japan in the late 1990s but current research suggests that the condition is much more widespread than previously thought.


Alan Teo, an associate professor at Oregon Health and Science University, has been researching hikikomori for more than a decade. He says it’s time the condition was given a clearer definition to enable more effective treatments worldwide.

What is your new thinking on the definition of hikikomori?

We’re trying to revise the definition of hikikomori based on new information, new knowledge, new science and the combined experience that I’ve had interacting with individuals who have it, as well as my Japanese collaborator.

In a nutshell, the core feature of hikikomori is the sense of physical isolation in the home, whatever that home is.

I think a misunderstanding that has happened among the lay population is to think of hikikomori only as being the most extreme. I’ve talked with hikikomori who haven’t left their room, or who haven’t been out of their home for many, many years. But, they are much more extreme examples.

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One of the messages here is that the definition also includes milder forms of social withdrawal.

Specifically, we’re saying that if you only leave the home three days a week or less, we’re proposing that figure to be the threshold for social withdrawal. In other words, the threshold to meet the definition of hikikomori.

Obviously the name’s Japanese, and that’s where hikikomori was first identified, but there’s more research coming out that it’s not a uniquely Japanese problem, is it?

No, it isn’t [uniquely Japanese]. That’s one of the reasons why I think it’s important that we’ve put out this new definition. There are clearly many reports of hikikomori from all over the world.

In addition, there’s more and more energy and excitement among scientists and researchers surrounding the subject. I’m getting contacted on a regular basis by researchers in France, Turkey and many other countries, who would like to study it.

One of the first steps in research is having a definition that you can operationalise. What that means is that we take a definition, and then we turn that definition into criteria that we can eaily measure.

So, using that example of physical isolation that I brought up as being the core criteria, it is relatively easy to measure how often a person leaves their home. And this is one of the reasons I’ve included this measure in the new definition. This is something that scientists across countries and in different cultures can use and apply the definition consistently.

Are there any common features among people who are affected by hikikomori?

I think each person is an individual, and of course, there’s lots of variation even within a culture. That said, when I listened to stories of hikikomori, there are some common threads.

Usually, hikikomori develops over an extended period of time. It isn’t like a switch that just suddenly turns on. People with hikikomori often have had major stressors early in their life, such as bullying or academic difficulties in school. They may even have faced problems with attending school in the first place.

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And that can fester and build up over time, turning into this prolonged social withdrawal that we see.

It’s likely they may also have challenges within their family relationships. So, let’s say that the 16-year-old son is hikikomori. He may be having difficulties with his parents, or his parents may be having difficulty in how they communicate and relate to their son. So, things like that.

Conflict within the family, difficulty with school or other early traumatic experiences – it all builds up over time until it reaches this syndrome of social withdrawal.

How would you research something like this? it seems that there may be difficulties in even contacting these people in the first place…

You’re hitting the nail on the head there. This has been one of the biggest impediments to moving research forward regarding hikikomori.

But there are also other impediments to moving research forward – funding, for example. But certainly, the difficulty of reaching out and getting individuals with hikikomori to participate in research has been a major barrier.

There’s a couple of thoughts that we have had in terms of trying to get around this. One of my interests is to do more research with family members because they are usually the first people to reach out for help.

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I regularly get emails out of the blue, but they’re almost always from a brother, from a mother, from an aunt. Someone who says: “It is really tearing our family apart. Can you help us?” So, the family is the first point of contact, and they could be really helpful with regards to early identification.


We know that there’s a significant delay in terms of how long it actually takes for us to identify a case, and if family members are more engaged and can identify signs of hikikomori early on, then maybe we can intervene earlier and do better at treating the condition.


Jason Goodyer
Jason GoodyerCommissioning editor, BBC Science Focus

Jason is the commissioning editor for BBC Science Focus. He holds an MSc in physics and was named Section Editor of the Year by the British Society of Magazine Editors in 2019. He has been reporting on science and technology for more than a decade. During this time, he's walked the tunnels of the Large Hadron Collider, watched Stephen Hawking deliver his Reith Lecture on Black Holes and reported on everything from simulation universes to dancing cockatoos. He looks after the magazine’s and website’s news sections and makes regular appearances on the Instant Genius Podcast.