Hikikomori: experience in Japan and international relevance
Authors: Takahiro A. Kato, Shigenobu Kanba, Alan R. Teo
Journal: World Psychiatry (2018)

The appearance of people in Japan, especially young men, who stopped going to school or the workplace and spent most of the time withdrawn into their homes for months or years, came to be seen as an increasing social phenomenon called Shakaiteki hikikomori (social withdrawal) by the late 1990s1. A community-based survey published in 2010 reported that the prevalence of hikikomori was approximately 1.2% of the Japanese population2, and in 2016 a Japanese cabinet report estimated people with hikikomori to be about 541,000 within the age range of 15-39 years. Early epidemiological studies were limited by not being based on strict diagnostic standards. In 2010, Japan's Ministry of Health, Labour and Welfare announced a guideline for hikikomori which included a definition ("a situation where a person without psychosis is withdrawn into his/her home for more than six months and does not participate in society such as attending school and/or work")3. More recently, in order not only to diagnose but also to assess the severity of the condition, we proposed even more precise diagnostic criteria based on the levels of physical isolation at home, avoidance of social interactions, and functional impairment or distress, as well as a sustained duration of six months or more4. The Japanese sociocultural background has been traditionally permeated by "amae" (accepting overdependent behaviors) and shame, which may underlie the culture-bound syndrome called Taijin Kyofusho (a severe form of social phobia) as well as hikikomori5, 6. Parent-child relationships in Japan have long been considered less oedipal than in Western societies and marked by an absent father and an extremely prolonged and close bond to the mother, which may result in difficulty to become independent7. Especially in hikikomori, the development of basic interpersonal skills during the early stages of life seems to be insufficient, which can induce vulnerability to stress in later school/workplace environments and lead to escape from social situations7. On the other hand, hikikomori-like cases have recently been reported in other countries of varying sociocultural and economic backgrounds such as Hong Kong, Oman and Spain, and our studies based on structured interviews have revealed the existence of hikikomori in India, South Korea and the US4. Thus, hikikomori has now crossed the limits of a culture-bound phenomenon to become an increasingly prevalent international condition. A major contributing factor may be the evolution of communication from direct to increasingly indirect and physically isolating8. This is especially the case for social interactions which hitherto required face-to-face contacts in a mutual physical space but can now occur, at least partially, in a virtual world. Through our recent study using the Structured Clinical Interview for DSM-IV Axis I Disorders, we have found that hikikomori may be comorbid with various psychiatric disorders, including avoidant personality, social anxiety disorder and major depression9. In addition, autistic spectrum disorders and latent or prodromal states of schizophrenia may have some overlapping symptomatology with hikikomori. Thus, hikikomori is now understood to have links to several mental illnesses, and we hypothesize that some common psychopathological mechanisms may exist in the act of "shutting-in" regardless of psychiatric diagnosis. Currently, there are more than fifty government-funded community support centers for hikikomori located throughout the prefectures of Japan, providing services such as telephone consultations for family members, the creation of "meeting spaces" for affected people, and job placement support. In addition, various private institutions provide treatment for hikikomori sufferers. However, there is yet to be a unified evidence-based method for these public/private interventions. A 4-step intervention is recommended by the government guideline for hikikomori, including family support and first contact with the individual and his/her evaluation; individual support; training through an intermediate-transient group situation (such as group therapy); and social participation trial3. We have recently established a hikikomori clinical research unit in a university hospital to develop evidence-based therapeutic approaches in collaboration with public/private hikikomori support centers. As a first step, we are trying to establish an evidence-based educational program for parents of individuals with hikikomori, because in the majority of cases the first consultation is made by them. Due to prejudice and lack of knowledge, in many cases family members cannot respond directly to individuals with this problem, are unable to intervene at all, and tend to turn a blind eye for many years without seeking help. Thus, we believe that education of parents to deal with hikikomori sufferers is essential for early intervention. Within decades, following further advances in Internet society, more and more people may come to live a hikikomori-like existence, which may or may not be seen as a pathological condition at that time. Hikikomori is still a hidden epidemic in many countries and, to grasp its worldwide relevance, diagnostic criteria should be included in ICD-11 and future DSM systems. In addition, evidence-based evaluation tools such as structured diagnostic interviews, screening instruments and online systems should be developed for international and population-level epidemiological surveys. Such tools will also help to evaluate risk factors and effectiveness of interventions. Takahiro A. Kato1, Shigenobu Kanba1, Alan R. Teo2 1Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; 2Department of Psychiatry, Oregon Health and Science University, Portland, OR, USA