The evolution of understanding of hikikomori

In the mid-2000s, one of us (Y.N.) presented an introduction to the concept of internet-based psychotherapy to the Japanese parliament as a potential accessible intervention for what appeared to be an epidemic of hikikomori. Almost 20 years later, hikikomori remains a significant problem and it is now recognised and studied as a global phenomenon rather than a culturally specific condition.^{Reference Kanai, Kitamura, Zha, Tanaka, Ikeda and Sobue2–Reference Tan, Lee and Kato4}

The definition of hikikomori has evolved from Saito's original description, in consideration of the severity of the confinement, acknowledging that some individuals may leave their homes despite avoiding social interactions.^{Reference Nonaka and Sakai5} The distinction is also made between the pathological and non-pathological (no significant functional impairment and distress associated with the social isolation) expression of hikikomori.^{Reference Kato, Sartorius and Shinfuku1} Moreover, although the initial Japanese Cabinet Office's definition of hikikomori excluded individuals with physical and mental disorders, some researchers have emphasised the importance of considering co-occurring conditions.^{Reference Koyama, Miyake, Kawakami, Tsuchiya, Tachimori and Takeshima6–Reference Orsolini, Bellagamba, Volpe and Kato8} It is argued that hikikomori, as a behaviour, tends to co-occur with other diagnoses, and therefore comorbidities should not be used as exclusion criteria.^{Reference Tan, Lee and Kato4} Perhaps the most important/critical relationship is with neurodevelopmental disorders, particularly autism.^{Reference Dell'Osso, Amatori, Muti, Giovannoni, Parri and Violi9} Thus, the concept of ‘secondary hikikomori’ was proposed to define such cases, where severe social withdrawal behaviour is a manifestation or consequence of another psychiatric disorder.^{Reference Pozza, Coluccia, Kato, Gaetani and Ferretti10} However, for some conditions, it could be argued that it would be difficult to identify whether hikikomori is indeed secondary or whether it is the primary disorder. Consequently, a standardised definition is important for both clinical and research perspectives.^{Reference Tan, Lee and Kato4} One approach might be to view the expression of hikikomori as a spectrum, where the variation in severity of the condition can be manifested by level of confinement and impact on function. This approach allows identification of comorbid conditions, while appreciating that symptoms are likely to overlap and may inform about their potential effect on expression of hikikomori. Interestingly, there is also a proposal to consider hikikomori as a diagnostic specifier rather than a stand-alone condition, so that certain mental health conditions can present with or without hikikomori-like social isolation.^{Reference Orsolini, Longo, Bellagamba, Kato and Volpe11}

Transcultural view of hikikomori

There is now a consensus that the general hikikomori phenomenon is not confined to Japan; it also exists across the globe.^{Reference Kanai, Kitamura, Zha, Tanaka, Ikeda and Sobue2–Reference Tan, Lee and Kato4} This raises questions about the relevance of traditional Japanese culture as a causal link to hikikomori.

Family structure and relationships between parents and their children vary across cultures. ‘Amae’ refers to an overdependent and enmeshed parent–child relationship and is an extensively studied aspect of Japanese culture that was proposed to play a role in the development of hikikomori.^{Reference Tan, Lee and Kato4} Interestingly, the same concept may apply in Middle Eastern cultures, where extended family structure and similar acceptance of dependency are noted,^{Reference Okasha, Elkholy and El-Ghamry12} although to our knowledge only one case report from Oman^{Reference Sakamoto, Martin, Kumano, Kuboki and Al-Adawi3} has been published to date. However, it is pointed out that maladaptive and dysfunctional family behaviour regardless of cultures (the absence of effective communication and emotional interaction, coupled with a lack of empathy towards children) contributes to the formation of hikikomori.^{Reference Orsolini, Bellagamba, Longo, Volpe and Kato13}

Hikikomori is also suggested to be linked to excessive video/computer gaming, but this relationship is complex.^{Reference Kato, Sartorius and Shinfuku1} It is currently not clear whether a causal link between hikikomori and pathological computer gaming exists, and it is likely to present a chicken and egg conundrum. While some researchers consider hikikomori to be a risk factor for pathological gaming, others argued that the use of games during early hikikomori could be a coping strategy by having some social involvement in the virtual world.^{Reference Kato, Sartorius and Shinfuku1} However, it remains uncertain whether the current worldwide increases in gaming will lead to a prevalence of hikikomori in other countries that is comparable to that in Japan. This could be because hikikomori is related to other factors, including cultural ones.

Writing this article from within the UK, it should be noted that hikikomori has increasing relevance, as is likely in many other Western countries. This is particularly shaped by social and technological changes and economic crises. The coronavirus-19 (COVID-19) pandemic led to severe restrictions and social isolation, which might have contributed to the emergence of hikikomori-like behaviour in young adults. Early adulthood remains a critical window for possible onset of hikikomori,^{Reference Kato, Sartorius and Shinfuku1,Reference Kanai, Kitamura, Zha, Tanaka, Ikeda and Sobue2} and young people were disproportionately disadvantaged by COVID-19 restrictions.^{Reference Rooksby, Furuhashi and McLeod14} Now that the pandemic is largely over and individuals are re-engaging with the world, it is likely that we will witness the emergence of hikikomori or increased case numbers. It is thus of critical importance that hikikomori is recognised by Western psychiatry, as the number of cases is likely to have increased in line with related diagnoses, such as autism that features pathological demand avoidance, which have been increasingly identified over the past 20 years in the UK.^{Reference Russell, Stapley, Newlove-Delgado, Salmon, White and Warren15} Furthermore, more than a decade ago a high incidence of internet addiction and compulsive internet use (63%) was found in an adult British sample.^{Reference Quiñones-García and Korak-Kakabadse16} These disorders are recognised comorbidities with hikikomori, which poses the question whether hikikomori numbers are unknowingly growing. Research into hikikomori is still limited in the UK and the term itself is not widely recognised among Western psychiatrists. Even though social withdrawal appears to be a cardinal presentation of psychological distress among young adults in Japan, it may not be the primary manifestation in the other countries, where different mental health presentations may be more evident.^{Reference Bor, Dean, Najman and Hayatbakhsh17}

Future perspectives

Over the past 20 years, global awareness of hikikomori has grown significantly, reflecting an increasing number of young individuals of working age withdrawing from society. The normalisation of staying at home and its perceived acceptability during the COVID-19 pandemic is likely to have further encouraged this pattern of coping behaviour, with social media use serving as a compensatory mechanism for mental health problems.^{Reference Orsolini, Volpe, Albert, Carmassi, Carrà and Cirulli18} Since ‘hikikomori’ is not yet a recognised diagnostic term in DSM-5 or ICD-11, extreme cases of withdrawal outside of Japan are likely to be classified among other mental health conditions, including depression, anxiety disorders or agoraphobia. Although the globalisation of the concept of hikikomori highlights concerns about the mental health of young people, the causation of social withdrawal and its presentation and treatment options are still likely to reflect cultural differences. A key global recognition is that the rise in hikikomori cases, combined with a declining birth rate in affected countries, will significantly influence social demographics. The resulting decrease in the workforce will have a profound impact on future social care systems. In Western societies, including the UK, a systematic investigation of the prevalence of severe social withdrawal of young adults is necessary, and increasing the awareness of hikikomori and recognition of its risk factors in different societal and cultural contexts will aid understanding and available treatment options for many people currently distant from care.