The word hikikomori was recently added to the Oxford Dictionary of English [1
] where it joins other words of Japanese origin such as otaku (person with obsessive interests) and karoshi (death from overwork). It is defined as ‘the abnormal avoidance of social contact, typically by adolescent males’. Hikikomori was first introduced to the public when a Japanese psychiatrist, Tamaki Saito, published a book with this word in its title in 1998 [2
]. In his book “Social Withdrawal (shakaiteki hikikomori
): A Neverending Adolescence”, Saito defined hikikomori provisionally as ‘those who withdraw entirely from society and stay in their own homes for more than six months, with onset by the latter half of their twenties, and for whom other psychiatric disorders do not better explain the primary causes of this condition’. Since then, the word hikikomori has been used widely in Japan and has more recently been reported in the foreign media and discussed in medical journals by psychiatrists from other countries [3
]. Much of this attention occurred without a thorough discussion of its precise definition [14
In May 2010, a research group supported by the Japanese government published guidelines for the assessment and treatment of hikikomori [18
]. The guidelines defined hikikomori as the following: ‘A phenomenon in which persons become recluses in their own homes, avoiding various social situations (e.g. attending school, working, having social interactions outside of the home etc.) for at least six months. They may go out without any social contact with others. In principle, hikikomori is considered a non-psychotic condition distinguished from social withdrawal due to positive or negative symptoms of schizophrenia. However, there is a possibility of underlying prodromal schizophrenia’.
These guidelines were based on a number of studies including the analysis of 184 consecutive hikikomori cases at five different mental health centers (Kondo’s survey cited in the guidelines [18
]; unpublished), the investigation of hikikomori youths referred to psychiatric emergency services (Nakashima’s survey cited in the guidelines [18
]; unpublished), and a nationwide survey conducted as a part of the WHO World Mental Health Initiatives (WMH-J) [19
]. The WMH-J survey selected subjects from voter registration lists in various parts of Japan, interviewed a total of 4,134 respondents aged 20–49 (response rate: 55.1%) and demonstrated that a total of 1.2% had experienced hikikomori. They estimated that there are 232,000 ongoing hikikomori cases in Japan. Furthermore, in September 2010, the Cabinet Office of the Japanese government published results of their study on hikikomori and reported that the number of hikikomori was estimated to be 236,000 [20
]. These results demonstrate that hikikomori is a common problem in Japan.
In this study, we conducted a questionnaire survey of hikikomori with 1,038 subjects. Because psychiatrists and pediatricians tend to have the most clinical contact with hikikomori individuals, we included additional questions regarding potential underlying psychiatric conditions of hikikomori for the psychiatrists and pediatricians participating in the study. The overall aim of this study is to gain a better understanding of the perception of hikikomori amongst health-related students and professionals and to explore possible psychiatric conditions underlying hikikomori.