The ‘Hikikomori’ syndrome: worldwide prevalence and co-occurring major psychiatric disorders: a systematic review and meta-analysis protocol

Abstract

IntroductionThe ‘Hikikomori’ syndrome (HS) consists of prolonged and severe social withdrawal. It has been studied first in Japan and recently has increasingly drawn the attention of researchers and clinicians all over the world. It is unclear whether it exists in other cultural contexts than Asia. The existing systematic reviews did not provide a quantitative synthesis on its prevalence. In addition, a summary of the co-occurring rates of psychiatric disorders is lacking. To provide a more comprehensive understanding of the clinical picture, it seems important to investigate which psychiatric disorders listed in the classification systems are most frequently associated with this psychological condition affecting young people. This paper describes a systematic review and meta-analysis protocol summarising worldwide prevalence of the HS in general population and clinical samples with psychiatric disorders. The review will also assess the co-occurrence between HS and each psychiatric disorder defined by any version of the Diagnostic and Statistical Manual of Mental Disorders (DSM) or International Classification of Diseases (ICD) in any clinical samples with psychiatric disorders.Methods and analysisA systematic review will be conducted according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Studies will be included if they use youth aged 12–35 years, recruited from general population or population with psychiatric disorders, if they use international criteria to diagnose HS. No restriction about design or language will be applied. The search will be conducted during the first week of November 2019 by two independent reviewers through the databases Scopus, PubMed, PsycINFO, Web of Science, by examining study references, by looking for conference proceedings/dissertations/theses, by contacting study corresponding authors. Random-effect meta-analysis will be performed by computing effect sizes as logit event rates. Study quality will be assessed through the Newcastle-Ottawa Scale.Ethics and disseminationThe current review does not require ethics approval. The results will be disseminated through conference presentations and publications in peer-reviewed journals.PROSPERO registration numberCRD 42018098747.

Quality of life and objective functional impairment in lumbar spinal stenosis: a protocol for a systematic review and meta-analysis of moderators

“…As in our previous meta-analytical works,11 45 the Newcastle-Ottawa Quality Assessment Scale (NOS) will be adopted by two independent meta-analysts to examine the methodological quality of each study 46. This checklist is based on a maximum score of nine: four points are assigned to inclusion criteria of cases and controls (definition of cases, selection of cases, definition of control subjects, selection of control subjects), two points are assigned to the comparability criteria of cases and control subjects according to study design and statistical analysis (comparability in terms of age and gender), and three points to exposure verification criteria of cases and control subjects (exposure verification, same method of verification, no response point).…”

The Hikikomori Phenomenon of Social Withdrawal: An Emerging Condition Involving Youth's Mental Health and Social Participation

“…The term hikikomori describes individuals who have withdrawn from their community. 3 The initial reports emphasized the close relation of the clinical manifestation with the local culture, as suggested by the name, which is a compound Japanese word made of 2 verbs indicating the attitude of an individual "to pull back" (hiku) and "to selfseclude" (komoru). 6 However, increasing reports from around the world provided a better understanding of this condition and suggested that hikikomori is a global health problem, which may exist as an independent primary diagnosis.…”

“…13 Hikikomori could be considered a new primary psychiatric disorder in future versions of the Diagnostic and Statistical Manual of Mental Disorders, despite the presence of some clinical overlap with other mental disorders. 3,14 Published reports have clarified the pathologic features of hikikomori, and have built a consensus regarding its clinical characteristics, complications, and management. 13 Individuals with hikikomori present a severe social isolation characterized by a marked physical self-inflicted seclusion in their home.…”

“…15,16 Therefore, the lack of consensus on diagnostic criteria, together with various sociocultural features involving a variety of cross-cultural factors, may account for the variable prevalence rates reported by the studies performed in different geographic areas. 3 The prevalence of hikikomori ranges from 0.87% to 1.2% in Japan, whereas in Hong Kong it is reported to be 1.9%, and 2.3% in Korea. 15,[17][18][19] In Italy, hikikomori is estimated to involve about 1.2% of the population between 0 and 18 years of age, and in Spain, reports show that in groups of persons affected by social withdrawal, individuals diagnosed as hikikomori are 12.6%.…”

“…A new severe and prolonged form of social withdrawal, called hikikomori from a Japanese word indicating selfseclusion, was observed typically among adolescents and youth transitioning to adulthood, living in economically advanced countries. 3,4 The objective of this editorial is to raise awareness on the burden and risks faced by adolescents developing this emerging form of social withdrawal. The hikikomori phenomenon is part of the group of new morbidities causing children and adolescents to limit their activity owing to a chronic health condition with attendant psychological problems.…”