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Smartphone distraction (SD) is closely related to depression, and the prevalence of SD among nursing students is gradually increasing. However, the potential mechanism of the effect of SD on nursing students' depression is unclear. A total of 574 nursing students were assessed using Smartphone Distraction Scale, Ruminative Response Scale, Hikikomori Questionnaire, and Patient Health Questionnaire-9. The results indicated that SD among nursing students had an impact on depression through four pathways: (1) SD was positively associated with depression (β = 0.353, P < 0.001); (2) Rumination (β = 0.199, 95% CI: 0.081 to 0.162) and social withdrawal (β = 0.061, 95% CI: 0.034 to 0.091) mediated the effects of SD on depression, respectively; and (3) Rumination and social withdrawal played a chain mediating role in the effect of SD on nursing students' depression (β = 0.027, 95% CI: 0.015 to 0.042). The negative impact of SD on nursing students' mental health should not be taken lightly. Schools and hospitals should guide nursing students to use smartphones correctly, including providing mental health education and professional psychological counselling; families could play a supervisory role and communicate regularly to understand the psychological state and learning of nursing students. These measures can help nursing students cope with stress and reduce the risk of depression., (© 2024. The Author(s).)

Objectives: The 25-item Hikikomori Questionnaire (HQ-25) is an instrument developed to measure a condition characterized by extreme social withdrawal that was first described in Japan. This study aimed to translate the HQ-25 into German and validate the German version (HQ-25-G)., Methods: Translation was conducted according to established guidelines. Validation was based on data from a quota sample of individuals living in Germany, ranging from 18 to 74 years old (representing the distribution of age, sex and federal state, n = 5000). Data collection occurred during August and September 2023. We tested reliability, construct validity and concurrent validity. Moreover, HQ-25 scores for key sociodemographic group were reported., Results: Internal reliability for the HQ-25-G was excellent (Cronbach's alpha = 0.93). We confirmed the original three-factor model. Moreover, higher hikikomori levels were significantly associated with more depressive symptoms (r = 0.50), more anxiety symptoms (r = 0.45), higher loneliness levels (r = 0.56), higher levels of objective social isolation (r = -0.47), higher levels of perceived social isolation (r = 0.59) and a higher preference for solitude (r = 0.45)., Conclusions: In a large population-based sample (including younger adults, middle-aged adults and older adults), the HQ-25-G version proves to be a psychometrically robust instrument, which is useful for further exploring the phenomenon of hikikomori within the German-speaking population., (© 2024 The Author(s). International Journal of Methods in Psychiatric Research published by John Wiley & Sons Ltd.)

The Japanese term hikikomori was first used to describe prolonged social withdrawal in the 1990s. Since then, research across the world have reported similar prolonged social withdrawal in many countries outside Japan. This study systematically analyses the evolution of literature on hikikomori in the past 20 years to gain a better understanding of the development of the knowledge base on hikikomori since it garnered attention in Japan. Findings from the scientometric review indicate many perspectives on the etiology of hikikomori including cultural, attachment, family systems and sociological approaches. However, similarities with modern type depression, a novel psychiatric syndrome, have been proposed and there are signs of a recent paradigm shift of hikikomori as a society-bound syndrome rather than a cultural-bound syndrome unique to Japan. As research into hikikomori continues to grow, results from the review also highlight the need for a more universally shared definition of hikikomori in order to better consolidate cross-cultural research for meaningful and valid cross-cultural comparisons which can help to promote evidence-based therapeutic interventions for hikikomori .

The term "hikikomori" was recognized by society between 1980 and 2000, when the term "NEET" also appeared and it was regarded as a problem of irresponsible youth. However, accumulation of surveys and research both in Japan and abroad, including those conducted by the Cabinet Office, has revealed that the reasons behind social withdrawal are not only limited to mental illness. There are many people who exhibit withdrawal because they are unable to establish relationships with the community and other people owing to various factors such as social systems, attachment formation, family background, and education. In other words, withdrawal is better described as a "symptom" or "condition" than a disease. Therefore, it is necessary to understand and analyze the diverse backgrounds and needs of individuals with withdrawal and confront them about their state. Currently, many hikikomori people with prolonged withdrawal are now in their 40s and 50s. With their parents' aging, there are cases where people with hikikomori and their families become socially isolated and are unable to make ends meet. It is undeniable that, until now, the society we live in as a whole has little interest in or understanding of hikikomori. In contrast, withdrawal among older adults (tojikomori), which has become a problem in the super-aging society. Tojikomori is defined as "going out less than once a week and not requiring nursing care", which is not equivalent with hikikomori. Owing to the decline in the frequency of going out among the elderly in the recent coronary crisis, the number of pre-frailty in older adults has become a nationwide problem.　Thus, both hikikomori and tojikomori are reversible conditions, and can be alleviated by providing necessary support. This paper summarizes the findings of the symposium "Challenges, Prevention, and Countermeasures for Social Withdrawal (Hikikomori) by Age Group" organized by the Committee on Mental Health and Suicide Prevention of the Japanese Society of Public Health at the 79th Annual Meeting of the Japanese Society of Public Health. This article is a compilation of findings that can benefit public health practitioners and researchers.

Objective: This review, which was registered with PROSPERO (CRD42021237988), aimed to systematically extract common elements in the hikikomori definition or criteria applied by researchers and examine cultural differences and chronological changes in the demographic characteristics of hikikomori individuals such as age, gender and hikikomori duration., Method: For inclusion in the review, the hikikomori criteria, age and gender of the hikikomori individuals had to be specified, and the article had to be peer-reviewed and written in Japanese or English, focusing on hikikomori individuals or their families. Case studies, reviews and qualitative studies were excluded., Results: The total sample size for the 52 studies included in the review was 4744. Over 80% of the studies included the elements 'not working or attending school', 'not socializing outside one's home' and 'duration of hikikomori' in their hikikomori criteria, and many studies included the element 'staying at home on most days except solitary outings'. A cross-temporal meta-analysis showed the possibility that the age of hikikomori individuals increased chronologically (β = 0.44, B = 0.50, 95% confidence interval = [0.16, 0.84]). Comparisons weighted by sample size between Japan and other countries showed the possibility that the age of hikikomori individuals was higher ( d  = 0.32), the percentage of males was lower ( d  = 0.91) and the hikikomori duration was shorter ( d  = 2.06) in studies conducted in countries other than Japan. However, many of the included studies had a high risk of selection bias, and this bias may have influenced the results obtained. Thus, the results of this study may represent the researcher's perception of hikikomori rather than accurately representing the actual condition of hikikomori., Conclusion: Researchers should specifically identify similarities and differences in the clinical picture of hikikomori and compare the studies to organize the findings derived from studies focusing on hikikomori.

Introduction: Hikikomori is a Japanese term etymologically derived from ' hiku ' (i.e. ' to pull back ') and ' komoru ' (i.e. ' seclude oneself '), which identifies those subjects who deliberately withdraw themselves by social life, remaining confined into their own home/room. The phenomenon is widely diffused in Japan, even though it is currently spread outside the Japanese culture. However, a universally shared and cross-cultural adaptation of Hikikomori definition, phenomenological and psychopathological characterization is still missing., Methodology: An expert-guided opinion paper was here provided to clinical characterize the Hikikomori-like social withdrawal in the Italian context, by considering the transformation from a family-based society to a 'fluid' digital-structured culture, also discussing the concept of modern-type depression. This was provided deepening the principal current studies available in literature and giving an interpretation based on clinical experience in the Italian society. The work was supervised through a consensus by the most international expert of Japanese Hikikomori syndrome., Results: Current individual, family and social trajectories may potentially act as a mediator in favouring the occurrence of Hikikomori-like social withdrawal also in western countries, including Italy. Despite the differences between Japanese and Italian society and culture, the recent shaping of family structure and intra-familial dynamics, typical of the current post-modern society, may potentially influence the emergence of psychopathologies not typical of Italian culture. Unemployment and 'Not in Employment Education or Training' (NEET) conditions may represent another potential risk factor for economical/social marginalization of youngsters, together with the recent dramatic emergence of web-based psychopathologies., Conclusion: A diagnostic culturally-adapted flow-chart is proposed for clinical characterizing Hikikomori in Italian context, which may help in proposing preventive strategies, ensuring early identification and prompt therapeutic interventions, particularly among youngsters.

Background: Social withdrawal (hikikomori) has become an internationally recognized phenomenon, but its pathology and related factors are not yet fully known. We previously conducted a statistical case-control study on adolescent patients with hikikomori in Japan, which revealed the non-specificity of pathology in patients with hikikomori. Further, environmental factors, such as the lack of communication between parents and Internet overuse, were found to be significant predictors of hikikomori severity. Here, we aimed to conduct a similar preliminary case-control study in France and to compare the results with those from the study conducted in Japan., Methods: Parents of middle school students who underwent psychiatric outpatient treatment for hikikomori (n = 10) and control group parents (n = 115) completed the Child Behavior Checklist to evaluate their child's psychopathological characteristics and the Parental Assessment of Environment and Hikikomori Severity Scales, as in our previous study in Japan. We compared the descriptive statistics and intergroup differences in France with those from the previous study conducted in Japan. In the multiple regression analysis to find predictors of hikikomori severity in French and also Japanese subjects, the same dependent and independent variables were chosen for the present study (both differed from the previous study). These were used in order to make accurate intercountry comparisons., Results: The comparisons revealed no differences in the pathology of hikikomori between Japan and France. Specifically, both studies found similarly increased scores for all symptom scales, with no specific bias. However, the statistical predictors of hikikomori severity in France (lack of communication between parents and child and lack of communication with the community) differed from those in Japan (lack of communication between parents)., Conclusion: Hikikomori in Japan and France could be considered essentially the same phenomenon; moreover, our findings demonstrated the universal non-specificity and unbiasedness of the hikikomori pathology. This suggests that hikikomori is not a single clinical category with a specific psychopathology; instead, it is a common phenotype with various underlying pathologies. However, different strategies may be required in each country to prevent the onset and progression of hikikomori., (© 2022. The Author(s).)

Objectives: Hikikomori - an almost complete withdrawal from social interaction first seen in Japan - is becoming an emerging psychological syndrome worldwide. The mental health community in Japan has focused on hikikomori since the 1990s. Hikikomori was initially considered a culture-bound trait, unique to Japan; however, it has become an international concern, and cases have been reported even outside of Japan. While home visiting support for people with hikikomori has gained popularity, an effective solution remains elusive. This paper describes the process involved in effective home visiting support provided by experienced workers to help people with hikikomori., Method: Semi-structured interviews were conducted with 21 home-visiting support workers in Japan. Collected data were analysed using a constant comparative method based on Grounded Theory., Results: 'Supporting them in finding their own way to participate in society' was identified as the core category. This core category was substantiated by following three interrelated stages: preparing the involved surroundings for reaching out to a person, maintaining constant communication and expanding the range of activities and relationships. The process encouraged people with hikikomori to enhance their social connections and improved their motivation for social participation. People with hikikomori experiencing despair and isolation began to find pleasure in social participation through the three stages of support provided by home-visiting workers., Conclusion: Our study suggests that Home visiting support for people with hikikomori can be enhanced by these three interrelated methods which can help individuals integrate into society and connect with others.

Deficits in social communication and interaction are core clinical symptoms characterizing multiple neuropsychiatric conditions, including autism spectrum disorder (ASD) and schizophrenia. Interestingly, elevated anxiety levels are a common comorbid psychopathology characterizing individuals with aberrant social behavior. Despite recent progress, the underlying neurobiological mechanisms that link anxiety with social withdrawal remain poorly understood. The present study developed a zebrafish pharmacological model displaying social withdrawal behavior, following a 3-h exposure to 4 μΜ (+)-MK-801, a non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist, for 7 days. Interestingly, MK-801-treated zebrafish displayed elevated anxiety levels along with higher frequency of stereotypical behaviors, rendering this zebrafish model appropriate to unravel a possible link of catecholaminergic and ASD-like phenotypes. MK-801-treated zebrafish showed increased telencephalic protein expression of metabotropic glutamate 5 receptor (mGluR5), dopamine transporter (DAT) and β 2 -adrenergic receptors (β 2 -ARs), supporting the presence of excitation/inhibition imbalance along with altered dopaminergic and noradrenergic activity. Interestingly, β 2 -ARs expression, was differentially regulated across the Social Decision-Making (SDM) network nodes, exhibiting increased levels in ventral telencephalic area (Vv), a key-area integrating reward and social circuits but decreased expression in dorso-medial telencephalic area (Dm) and anterior tuberal nucleus (ATN). Moreover, the co-localization of β 2 -ARs with elements of GABAergic and glutamatergic systems, as well as with GAP-43, a protein indicating increased brain plasticity potential, support the key-role of β 2 -ARs in the MK-801 zebrafish social dysfunctions. Our results highlight the importance of the catecholaminergic neurotransmission in the manifestation of ASD-like behavior, representing a site of potential interventions for amelioration of ASD-like symptoms., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Hikikomori, a clinical condition widely studied in Japan, is receiving increasing attention in Western Countries., Aims: This study aimed to create a new instrument for evaluating the risk of Hikikomori in both Eastern and Western countries., Methods: Through two studies on Italian adolescents, youths, and adults ( n  = 1,285) and a study on Japanese youths and adults ( n  = 392), we analyzed the psychometric properties of the Hikikomori Risk Inventory (HRI-24)., Results: We found support, in both the Italian and Japanese samples, for the good and stable factor structure of the scale (CFI = 0.94, RMSEA = 0.057 for both the adult samples), as well as for its convergent and divergent validity., Conclusions: The HRI-24 might be used in future studies in both Western and Eastern countries to shed light on the features of this clinical disorder in different cultures. This will allow the development of culture-sensitive preventive and clinical interventions.

Hikikomori is a Japanese term for social withdrawal, ranging from complete inability to venture outdoors to preferring to stay inside. The prevalence of hikikomori is high, up to 1.2% of the Japanese population, but only few studies have examined its emergence in adolescents. Therefore, we sought to identify environmental and psycho-behavioral characteristics related to hikikomori during adolescence. Parents of middle school students who underwent psychiatric outpatient treatment for hikikomori (n = 20) and control group parents (n = 88) completed the Child Behavior Checklist to evaluate their child's psycho-behavioral characteristics and novel scales to evaluate environmental characteristics and hikikomori severity. Scores for all eight Child Behavior Checklist subscales were significantly higher in the experimental group. Multiple regression analysis revealed that "anxious/depressed," "somatic complaints," "lack of communication between parents" and "overuse of the Internet" were significant predictors of hikikomori severity. These findings can help identify individuals who are at risk of developing hikikomori., (© 2020. The Author(s).)

Involvement in romantic relationships is a salient developmental task in late adolescence and early adulthood, and deviations from normative romantic development are linked to adverse outcomes. This study investigated to what extent social withdrawal contributed to deviations from normative romantic development, and vice versa, and the interplay between withdrawal and couples' relationship perceptions. The sample included 1710 young adults (55-61% female) from the Tracking Adolescents' Individual Lives Survey cohort and their romantic partners. Data were collected across 4 waves, covering romantic relationships from ages 17 to 29 years. The results showed that higher withdrawal predicted a higher likelihood of romantic non-involvement by adulthood, consistently being single at subsequent waves, and entering one's first relationship when older. Withdrawal moderately decreased when youth entered their first relationship. Male's withdrawal in particular affected romantic relationship qualities and dynamics. These results provide new insights into the developmental sequelae of withdrawn young adults' romantic relationship development., (© 2021. The Author(s).)

Background: Although several surveys have suggested that socioeconomic factors function as background variables for the incidence of hikikomori (prolonged social withdrawal), no research has directly examined whether socioeconomic indicators increase the incidence of hikikomori. This study aimed to examine the relationship between socioeconomic factors and the incidence of hikikomori using data from eight cross-sectional studies conducted by our group between 2010 and 2019., Methods: We used socio-economic data from national surveys and collected the demographic data of members of a multi-branch Japanese association for family members of hikikomori patients for the period of 2010-2019., Results: The results of the partial correlation analysis showed that the incidence probability of hikikomori increased in tandem with unemployment rates and household income. Further, the associations were positively strong in the 2010-2015 research period; however, they were absent, weak, or medium in the 2016-2019 research period., Conclusions: The findings suggest that socioeconomic factors relate to the increase in hikikomori, and that these factors should be considered when identifying the individual or cultural factors that cause hikikomori., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

Adolescence is a developmental period when spending time alone becomes particularly important. The aim of this study was to explore adolescents' experiences of solitude, with a focus on the implications of both spending too much time alone-as well as not enough time alone. Participants were N = 869 adolescents (15-19 years of age, M = 16.14, SD = 0.50), who completed a series of self report measures assessing time spent alone, activities while alone, social motivations (shyness, sociability), affect, and the recently introduced construct of aloneliness (i.e., negative feeling that arise from the perception that one is not getting enough time in solitude). Among the results, person-oriented analyses provided evidence of distinct subgroups of socially withdrawn adolescents (e.g., shy-withdrawn, unsociable, socially avoidant) as well as an alonely group (high aloneliness, low time alone). There was also preliminary support for the notion that solitary activity activities that are intrinsically motivated may be particularly effective at satisfying the need for solitude (and thereby reducing feelings of aloneliness). Taken together, these results highlight the importance of considering the implications of getting both too much-as well as not enough solitude for adolescents' well-being.

Objective: Hikikomori, from the Japanese words 'hiku' (to pull) and 'komoru' (to withdraw), is a clinical condition in which a subject locks himself/herself into his/her own house for more than 6 months. This condition is becoming relevant in Japan and other Asian countries, with new cases emerging in Europe and a steep increase in its incidence., Methods: In this article, the various psychopathological and diagnostic hypothesis and the different criteria proposed by the various authors have been analysed and compared, paying attention also to the new studies conducted in Europe and to therapeutic perspectives that are opening up for its treatment., Results: Numerous hypothesis have been put forward for the genesis of hikikomori, in particular, the hypothesis of a behaviour seen as a dysfuncion of the family system or as a result of our current modern society. Furthermore, this behaviour has been compared to other conditions such as internet addiction and a specific form of depression called Modern Type Depression (MTD)., Conclusions: Hikikomori could represent the clinical answer to a social evolution, similarly to other phenomena such as binge behaviours and use of psychoactive substances. Further studies are needed to clarify diffusion, diagnosticassessment and differential diagnosis.Key pointsHikikomori is now considered a contemporary society-bound syndrome linked to modern society changes.Hikikomori might be a coping strategy to avoid relationships, social judgement and possible failures.Hikikomori might represent an extreme suffering that needs to be identified early: it is linked to severe form of modern type depression and it is a risk factor for suicidal behaviours.It is important to inform and sensitise communities about hikikomori to assure early interventions.More clinical studies are needed to define a unitary and specific model of hikikomori and to structure focussed interventions.

The term hikikomori, or social withdrawal, was first coined in the late 1980s in Japan to describe adolescents and young adults who isolated themselves at home, withdrew from most social engagement, such as work or school, and had almost no relationships with others (except family members and online contacts) for longer than 6 months. Hikikomori often results from emotional injuries such as rejection, or failures that have not been addressed or even noticed. In the current case illustration, the problem of hikikomori is depicted through a client named Ken, a 40-year-old single man who, following graduation from university, became lodged in a 15-year cycle of repeatedly finding employment, quitting within the first year, and going into reclusive isolation. Ken underwent affect-oriented integrative psychotherapy for 4 years. The importance of processing emotional pain and highlighting positive emotional experiences to build a positive sense of self in working with hikikomori will also be discussed., (© 2021 Wiley Periodicals LLC.)

Social withdrawal is an early and common feature of psychiatric disorders. Hypothalamic-pituitary-adrenal (HPA)-axis activation through increased salivary cortisol (sC) and sympathetic activation through increased salivary alpha-amylase (sAA) may play a role. We aimed to study whether the link between increased sC and sAA on the one hand and depression on the other hand is mediated by social withdrawal. In this cross-sectional, observational study, sC and sAA measures were measured in seven saliva samples in 843 participants (231 psychiatric patients and 612 healthy controls). Social withdrawal was assessed through the Brief Symptom Inventory (BSI)-, the Short Form 36-, and the Dutch Dimensional Assessment of Personality Pathology social withdrawal subscales, and analyzed using linear regression and mediation analyses. On average, participants were 44.0 years old (SD = 12.8; 64.1% female). Basal and diurnal sAA were unrelated to any social withdrawal scale and depression. Certain sC measures were positively associated with the BSI social withdrawal subscale (i.e., area under the curve with respect to the increase, beta = 0.082, p = 0.02; evening sC value: beta = 0.110, p = 0.003; and mean sC value: beta = 0.097; p = 0.01). We found limited support for statistical mediation by social withdrawal (measured using a composite social withdrawal score) on the relationship between evening sC and depression. Thus, although we found no support for a role of basal and diurnal sAA in social withdrawal, HPA-axis activation may partly aggravate social withdrawal in depressive disorders., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Exposure to prolonged stress in critical developmental periods induces heightened vulnerability to psychiatric disorders, which may have sex-specific consequences. Here we investigate the neuronal circuits mediating behavioral changes in mice after chronic adolescent social isolation stress. Escalated aggression is exhibited in stressed males, while social withdrawal is shown in stressed females. In vivo multichannel recordings of free-moving animals indicate that pyramidal neurons in prefrontal cortex (PFC) from stressed males exhibit the significantly decreased spike activity during aggressive attacks, while PFC pyramidal neurons from stressed females show a blunted increase of discharge rates during sociability tests. Chemogenetic and electrophysiological evidence shows that PFC hypofunctioning and BLA principal neuron hyperactivity contribute to the elevated aggression in stressed males, while PFC hypofunctioning and VTA dopamine neuron hypoactivity contribute to the diminished sociability in stressed females. These results establish a framework for understanding the circuit and physiological mechanisms underlying sex-specific divergent effects of stress., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021. Published by Elsevier Inc.)

Aim: Hikikomori, a form of pathological social withdrawal, has been suggested to have comorbidity with autism spectrum disorder (ASD). This study aimed to clarify how characteristics of hikikomori are associated with ASD, including undiagnosed autism spectrum conditions (ASC), in clinical settings., Methods: A total of 416 clinical patients were recruited through the Mood Disorder/Hikikomori Clinic at Kyushu University Hospital. A total of 103 hikikomori cases and 221 clinical controls without hikikomori conditions were extracted using a semi-structured interview, and completed a series of self-rated scales, including the Japanese version of the Autism-Spectrum Quotient (AQ-J)., Results: Compared to non-hikikomori controls, hikikomori cases were more likely to have higher autistic tendency based on the AQ-J. The cases showed more severe subjective depressive symptoms based on the self-rated Beck Depression Inventory II, whereas no significant difference was found on interview-based severity evaluation using the Hamilton Depression Rating Scale. Comparison within hikikomori cases based on the AQ-J cut-off score revealed that hikikomori cases with high ASC were significantly more likely to have higher traits of modern-type depression, smaller social networks, and less social support., Conclusion: The present data suggest that hikikomori sufferers are more likely to have autistic tendency, and that hikikomori sufferers with high ASC may have much more difficulty in social communication and social interaction. In addition, those with high ASC may also have lower self-esteem and higher complaint tendencies as aspects of modern-type depression traits, which may relate to the occurrence of hikikomori. Thus, evaluating autistic tendencies is important for appropriate interventions in hikikomori. Further investigations should be conducted to validate our pilot findings using structured diagnostic systems of ASD., (© 2020 The Authors Psychiatry and Clinical Neurosciences published by John Wiley & Sons Australia, Ltd on behalf of Japanese Society of Psychiatry and Neurology.)

It is often assumed that oral hypofunction is associated with social withdrawal in older adults because decreased motor function is related to decreased oral function. However, few studies have examined the relationship between social withdrawal in older adults and oral function. This longitudinal study aimed to clarify the relationship between changes in the level of social withdrawal and oral function in independent older adults. Participants were 427 older adults aged 65 years or older who took part in a self-administered questionnaire from 2016 to 2017 (baseline), and again two years later (follow-up). At baseline, 17 items related to oral function and confounding factors related to withdrawal, physical condition, physical function, and cognitive function were evaluated. A Cox proportional hazard model was used to examine the oral functions that negatively impact social withdrawal. The following factors were significantly associated with the worsening of social withdrawal: the number of remaining teeth, gingival condition, occlusal force, masticatory efficiency, and items related to swallowing and dry mouth. Older adults with cognitive issues who walk slowly and have a weak knee extension muscle were also significantly more likely to have oral frailty. Those who were found to have oral frailty at baseline were 1.8 times more likely to develop withdrawal compared to those with robust oral function. The results indicated that the worsening of withdrawal was associated with oral hypofunction at baseline. Since oral hypofunction was associated with the worsening of social withdrawal in older adults, it is important to maintain older adults' oral function.

Defined by psychologist Tamaki Saito as a period of social isolation in the absence of any other clear mental health issues for a period of six months or longer, hikikomori (social withdrawal) emerged as a condition among Japanese youth in the late 1980s. Used as both a noun to identify those afflicted, as well as describe their condition, the word immediately captured the attention of the Japanese and international public. According to various government and third-party surveys, hikikomori number from approximately 500,000 to two million people. Thus, while hikikomori are understood to struggle with long bouts of loneliness and isolation from their peers and parents, due to constant anxiety over their inability to perform among Japan's competitive capitalist-oriented social expectations, both academics and professionals continue to struggle to comprehend exactly who hikikomori are and how to help them. Based on fieldwork at New Start, a non-profit organization located just outside the city limits of Tokyo that helps hikikomori recover, this article examines the ways residents at New Start navigate this uncertainty and gain moral agency. Drawing from over a dozen interviews with parents, clients, and staff conducted while working as a volunteer at New Start, I focus on three representative trajectories that demonstrate how residents navigate the competing discourses surrounding the clinical and social categories of hikikomori and NEET (Not in Education, Employment, or Training), through which they embark on a journey from economically unproductive recluses, to productive capitalist citizens pursuing their own version of a "nearly normal" life. I argue that the various accomplishments of hikikomori , as individuals and as a social category, which both support existing social relations and provide an alternative mode of fitting within them, is "the work of hikikomori ."

Background: Pathological social withdrawal, named "Hikikomori," is a Japanese culture-bound syndrome and a serious social problem in Japan. The number of Hikikomori cases in Japan was estimated at about 563,000 in 2016 according to governmental surveys. However, no studies have reported how many people with Hikikomori have access to community-based psychiatry clinics, and how different they are from non-Hikikomori patients regarding their baseline characteristics and outcomes. The aim of the present study is to evaluate the baseline characteristics, clinical attendance, and social functioning of community psychiatric clinic patients treated for social withdrawal at one-year follow-up., Method: Participants (n = 304) were all patients (aged under 65) of a psychiatric clinic in a one-year period. Baseline patient characteristics were compared among "current" Hikikomori patients, "past" Hikikomori," and "other" patients. Logistic regression analysis of clinic attendance status and social functioning at one-year follow-up was used to assess patient outcomes. Independent variables were age, gender, Hikikomori status, and support from clinical staff., Results: Numbers of "current", "past" Hikikomori, and "other" patients were 60 (19.7%), 81 (26.6%), and 163 (53.6%), respectively. The percentage of "current" Hikikomori who attended in person (56.7%) was significantly smaller than for "past" (92.6%) and "other" (92.6) (p < .001). The age distribution of "current" Hikikomori patients was bimodal, peaking at 20 and 40-45 years. The "current" state predicted significantly fewer regular visits (OR = 0.43; 95% CI = 0.22-0.83; p = .012); support from psychiatric social workers increased visits (OR = 2.35; 95% CI = 1.14-4.86; p = .021). Among the "current" Hikikomori patients, first visit attendance in person predicted regular attendance; no factor consistently predicted working/schooling status., Conclusion: A sizable percentage of community clinic patients experienced Hikikomori. The "current" Hikikomori state corresponded with low clinic attendance and social function; "support from clinical staff" may increase visit regularity; no factors consistently improved social functioning. Further multi-site study is warranted to examine the generalizability of the findings from the current single-center study.

Introduction: Social withdrawal can be problematic for adolescents, increasing the risk of poor self-efficacy, self-esteem, and academic achievement, and increased levels of depression and anxiety. This prospective study follows students across adolescence, investigating links between social withdrawal and two types of parenting hypothesized to impact or be reactive to changes in social withdrawal., Methods: Adolescent social withdrawal and parenting were assessed across seven years in a U.S. sample, beginning when students were in 6th grade and ending in 12th grade. The sample consisted of 534 adolescents (260 girls and 274 boys, 82% Euro- and 16% African-American). Social withdrawal was assessed in four grades using at least two informants (teachers, mothers, and/or adolescents). Mothers' and fathers' psychological control and monitoring-related knowledge were assessed by adolescents at two time points. A developmental cascade analysis was conducted using structural equation modeling to assess how withdrawal and control-related parenting impact each other transactionally over time. Analyses included a test for gender differences in the model., Results: The cascade model revealed that, controlling for previous levels of social withdrawal and parenting, earlier social withdrawal positively predicted psychological control and negatively predicted monitoring knowledge, and earlier parental psychological control-but not monitoring knowledge-predicted later social withdrawal. No adolescent gender differences were identified in the associations between social withdrawal and parental knowledge., Conclusions: This study offers insight into the mechanisms by which adolescents become more or less withdrawn over time, and suggests psychological control as a point of psychoeducation or intervention for parents., (Copyright © 2020 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.)

Oligodendrocyte (OL) and myelin development are crucial for network integration and are associated with higher brain functions. Accumulating evidence has demonstrated structural and functional impairment of OLs and myelin in serious mental illnesses. However, whether these deficits contribute to the brain dysfunction or pathogenesis of such diseases still lacks direct evidence. In this study, we conditionally deleted Olig2 in oligodendroglial lineage cells (Olig2 cKO) and screened the behavioral changes in adult mice. We found that Olig2 ablation impaired myelin development, which further resulted in severe hypomyelination in the anterior cingulate cortex. Strikingly, Olig2 cKO mice exhibited an anxious phenotype, aberrant responses to stress, and cognitive deficits. Moreover, Olig2 cKO mice showed increased vulnerability to social avoidance under the mild stress of social isolation. Together, these results indicate that developmental deficits in OL and myelin lead to cognitive impairment and increase the risk of phenotypes reminiscent of mental illnesses.

Objective: We compared clinic-referred youth with ADHD + sluggish cognitive tempo (SCT; n = 34), ADHD Only ( n = 108), and SCT Only ( n = 22) on demographics, co-occurring symptomatology, comorbid diagnoses, and social functioning. Method: In total, 164 youth (age = 6-17 years, M = 9.97) and their parent(s) presented to an outpatient clinic for a psychoeducational assessment. Between-group analyses and regressions were used to examine study variables. Results: SCT groups were older and exhibited more parent-reported internalizing problems, externalizing problems, sleep problems, and social withdrawal on the Child Behavior Checklist. No significant differences emerged between groups on the Teacher Report Form. Regression analyses involving multiple covariates revealed that SCT symptoms were uniquely related to social withdrawal but not general social problems. Conclusion: Based on parent report, SCT symptoms have a unique relationship with internalizing problems, sleep problems, and social withdrawal. Future research should explore correlates of SCT in youth using multiple informants.

Generalized anxiety disorder (GAD) sometimes exists in the background of social withdrawal and school refusal. Although clinical evidence suggests that selective serotonin reuptake inhibitors (SSRIs) are an effective treatment for GAD, they are not officially approved for GAD in Japan. In addition, it has been established that the use of SSRIs increases the risk for suicide and activation syndrome among young individuals. As such, there is currently little domestic clinical experience in prescribing SSRIs to young patients with GAD. The authors report two cases involving 10-year-old patients with GAD who were treated successfully with escitalopram and experienced subsequent improvement in social withdrawal and school refusal. One patient had autistic spectrum disorder and exhibited self-harm associated with anxiety symptoms, requiring careful use of SSRIs under hospitalization. The other patient was treated at an outpatient clinic without any side effects. In each case, improvement of anxiety symptoms with the use of SSRIs facilitated the introduction of psychoeducation and psychotherapy. It is important to accurately diagnose GAD, which may exist in the background of patients exhibiting social withdrawal and school refusal, and to treat the disorder appropriately. J. Med. Invest. 67 : 355-357, August, 2020.

Hikikomori (social withdrawal that lasts six months or longer) is a growing problem among Japanese adolescents and young adults, with recent estimates that approximately 1% of Japanese youths will suffer from an episode of hikikomori in their lifetimes. What remains unclear is whether hikikomori is a culture-bound syndrome or a condition impacting youths around the globe. Hence, the self-reported prevalence and psychosocial correlates of past experiences with hikikomori were examined in cross-sectional samples of university students from Singapore ( n  = 147), Nigeria ( n  = 151), and the United States ( n  = 301). Following tests of measurement invariance, comparisons showed that past experiences with hikikomori were related to elevated levels of current loneliness and depressive symptoms in each sample. However, analyses also revealed evidence of cultural variation in both the prevalence and the psychosocial correlates associated with past experiences of hikikomori, which taken together, provide preliminary evidence that the culture-bound characterization of hikikomori may not be appropriate.

Background: Hikikomori is a severe form of social withdrawal, originally described in Japan but recently reported in other countries. Debate exists as to what extent hikikomori is viewed as a problem outside of the Japanese context., Objective: We aimed to explore perceptions about hikikomori outside Japan by analyzing Western language content from the popular social media platform, Twitter., Methods: We conducted a mixed methods analysis of all publicly available tweets using the hashtag #hikikomori between February 1 and August 16, 2018, in 5 Western languages (Catalan, English, French, Italian, and Spanish). Tweets were first classified as to whether they described hikikomori as a problem or a nonproblematic phenomenon. Tweets regarding hikikomori as a problem were then subclassified in terms of the type of problem (medical, social, or anecdotal) they referred to, and we marked if they referenced scientific publications or the presence of hikikomori in countries other than Japan. We also examined measures of interest in content related to hikikomori, including retweets, likes, and associated hashtags., Results: A total of 1042 tweets used #hikikomori, and 656 (62.3%) were included in the content analysis. Most of the included tweets were written in English (44.20%) and Italian (34.16%), and a majority (56.70%) discussed hikikomori as a problem. Tweets referencing scientific publications (3.96%) and hikikomori as present in countries other than Japan (13.57%) were less common. Tweets mentioning hikikomori outside Japan were statistically more likely to be retweeted (P=.01) and liked (P=.01) than those not mentioning it, whereas tweets with explicit scientific references were statistically more retweeted (P=.01) but not liked (P=.10) than those without that reference. Retweet and like figures were not statistically significantly different among other categories and subcategories. The most associated hashtags included references to Japan, mental health, and the youth., Conclusions: Hikikomori is a repeated word in non-Japanese Western languages on Twitter, suggesting the presence of hikikomori in countries outside Japan. Most tweets treat hikikomori as a problem, but the ways they post about it are highly heterogeneous., (©Victor Pereira-Sanchez, Miguel Angel Alvarez-Mon, Angel Asunsolo del Barco, Melchor Alvarez-Mon, Alan Teo. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 29.05.2019.)

Shyness has been well established as a hindrance to social adjustment and may be problematic for emerging adults attending university, given the high social expectations placed upon students. Previous studies suggest emerging adults high in shyness recruit their friends to act as social surrogates in order to help reduce the stress of entering social interactions; yet, whether other less studied forms of social withdrawal (i.e., avoidance, unsociability) are associated with social surrogacy remains uninvestigated. The goal of the present study was to examine differences between subtypes of withdrawal as related to social surrogacy, while considering the roles of social anxiety and social self-efficacy. Participants were 961 emerging adults (76% female; 67% Caucasian) between the ages of 18 and 25 (M = 20.15, SD = 1.71). The results indicated that patterns of social surrogacy varied between withdrawal subtypes, such that social surrogacy was positively related to shyness, and negatively related to unsociability, whereas avoidance yielded mixed results. The findings highlight the importance of considering withdrawal motivations in understanding social surrogacy.

The human social brain is complex. Current knowledge fails to define the neurobiological processes underlying social behaviour involving the (patho-) physiological mechanisms that link system-level phenomena to the multiple hierarchies of brain function. Unfortunately, such a high complexity may also be associated with a high susceptibility to several pathogenic interventions. Consistently, social deficits sometimes represent the first signs of a number of neuropsychiatric disorders including schizophrenia (SCZ), Alzheimer's disease (AD) and major depressive disorder (MDD) which leads to a progressive social dysfunction. In the present review we summarize present knowledge linking neurobiological substrates sustaining social functioning, social dysfunction and social withdrawal in major psychiatric disorders. Interestingly, AD, SCZ, and MDD affect the social brain in similar ways. Thus, social dysfunction and its most evident clinical expression (i.e., social withdrawal) may represent an innovative transdiagnostic domain, with the potential of being an independent entity in terms of biological roots, with the perspective of targeted interventions., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Trans-diagnostic, domain- or symptom-focused approaches have been heralded as advancing psychiatric research, but relatively few clinical research programmes have been undertaken to leverage their potential. In this manuscript we describe the approach and protocol for an exploratory study, PRISM (Psychiatric Ratings using Intermediate Stratified Markers), that will be conducted to explore the biomarkers in schizophrenia (SZ) and Alzheimer's Disease (AD) that may be related to a common symptom, social withdrawal. Patient participants (N = 72 SZ and N = 72 AD study completers), will complete a series of fMRI, EEG, and behavioural paradigms, as well as contributing blood-derived (e.g. epigenetic) and smartphone data related to social behaviour. Self- as well as caregiver- and researcher-reported assessments will be provided to characterise social withdrawal. Normative data will also be collected from a group of healthy controls (N = 48 study completers), half of whom will be matched in terms of age and gender distribution to the SZ and AD group, respectively. Thus we will explore both differentiation and cross-diagnostic overlap in the biomarkers associated with different levels of social withdrawal in SZ and AD. In this way we aim to provide a deeper understanding of the biological underpinnings of symptomatology common to both disorders, and provide insights into novel treatment targets and future drug development approaches., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Central nervous system diseases are not currently diagnosed based on knowledge of biological mechanisms underlying their symptoms. Greater understanding may be offered through an agnostic approach to traditional disease categories, where learning more about shared biological mechanisms across conditions could potentially reclassify sub-groups of patients to allow realisation of more effective treatments. This review represents the output of the collaborative group "PRISM", tasked with considering assay choices for assessment of attention and working memory in a transdiagnostic cohort of Alzheimer's disease and schizophrenia patients exhibiting symptomatic spectra of social withdrawal. A multidimensional analysis of this nature has not been previously attempted. Nominated assays (continuous performance test III, attention network test, digit symbol substitution, N-back, complex span, spatial navigation in a virtual environment) reflected a necessary compromise between the need for broad assessment of the neuropsychological constructs in question with several pragmatic criteria: patient burden, compatibility with neurophysiologic measures and availability of preclinical homologues., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The PRISM (Psychiatric Ratings using Intermediate Stratified Markers) project was funded under the auspices of the European Union Innovative Medicine Initiative (EU-IMI) to explore quantitative approaches to the biological and behavioral aspects of neuropsychiatric disorders. PRISM focuses specifically on social withdrawal, although its principles are applicable to a wide range of disorders. This commentary explores some of the major aspects of the PRISM design from the perspective of the Research Domain Criteria (RDoC) project initiated by the National Institute of Mental Health. PRISM represents an apt exemplar of the principles developed in the RDoC framework, with the potential to contribute palpable advances in precision diagnosis and innovative approaches to treatment development., (Copyright © 2018. Published by Elsevier Ltd.)

Social withdrawal is one of the first and common signs of early social dysfunction in a number of important neuropsychiatric disorders, likely because of the enormous amount and complexity of brain processes required to initiate and maintain social relationships (Adolphs, 2009). The Psychiatric Ratings using Intermediate Stratified Markers (PRISM) project focusses on the shared and unique neurobiological basis of social withdrawal in schizophrenia, Alzheimer and depression. In this paper, we discuss the working definition of social withdrawal for this study and the selection of objective and subjective rating scales to assess social withdrawal chosen or adapted for this project. We also discuss the MRI and EEG paradigms selected to study the systems and neural circuitry thought to underlie social functioning and more particularly to be involved in social withdrawal in humans, such as the social perception and the social affiliation networks. A number of behavioral paradigms were selected to assess complementary aspects of social cognition. Also, a digital phenotyping method (a smartphone application) was chosen to obtain real-life data., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Aim: Hikikomori, a form of severe social withdrawal, is an emerging issue in mental health, for which validated measurement tools are lacking. The object was to develop a self-report scale of hikikomori, and assess its psychometric properties and diagnostic accuracy., Methods: A sample of 399 participants from clinical and community settings completed measures. Psychometric properties were assessed with factor analysis; diagnostic accuracy was compared against a semi-structured diagnostic interview., Results: The Hikikomori Questionnaire contained 25 items across three subscales representing socialization, isolation, and emotional support. Internal consistency, test-retest reliability, and convergent validity were all satisfactory. The area under the curve was 0.86 (95% confidence interval, 0.80-0.92). A cut-off score of 42 (out of 100) was associated with a sensitivity of 94%, specificity of 61%, and positive predictive value of 17%., Conclusion: The 25-item Hikikomori Questionnaire (HQ-25) possesses robust psychometric properties and diagnostic accuracy in an initial sample of Japanese adults. Additional research on its psychometric properties and ability to support clinical assessment of hikikomori is warranted., (© 2018 The Authors. Psychiatry and Clinical Neurosciences published by John Wiley & Sons Australia, Ltd on behalf of Japanese Society of Psychiatry and Neurology.)

Introduction: Researchers have identified a variety of motivations for solitude and for social withdrawal. These motivations may differ across cultures. The purpose of this study was to explore Ugandan adolescents' descriptions of solitude and social withdrawal, with the aim of guiding future research on social withdrawal in Uganda., Methods: Ugandan adolescents' (M = 14.23 years old, SD = 1.63 years) descriptions of solitude and social withdrawal were investigated in a cross-sectional, exploratory study. The sample (N = 219 [106 girls, 90 boys, 23 missing sex data]) was drawn from two primary schools and a secondary school in Eastern Uganda. Adolescents' responses to open-ended questionnaire items about general solitude, conflicted motivations for social withdrawal, and non-conflicted motivation for social withdrawal were coded and categorized., Results: Some of the adolescents' descriptions were consistent with the literature. For example, they described shyness and internalizing emotions, externalizing and socially incompetent behaviors, and poor peer relationships. Some descriptions were unique and likely reflected Uganda's challenges, for instance, family or household factors such as being an orphan., Conclusions: Results underscored the importance of exploring contextual processes (e.g., parental loss) that might affect Ugandan adolescents' solitude. More generally, the results suggested that solitude should be researched using a broad, synergistic lens that incorporates potential determinants from adolescents and their environments at multiple levels (e.g., person, peer, household, culture)., (Copyright © 2018 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.)

A cross-sectional study was designed to understand the impacts of "hikikomori" lifestyle on physical health. A total of 104 eligible hikikomori cases were recruited from the social services network of Hong Kong with a mean age of 19.02 ± 3.62 (ranged 13-31) year-old, and had completed the set of questionnaires and a series of anthropometric and physical health measurements. Despite SF36 score of 84.0 indicated good physical functioning in general, participants were lived sedentarily with high incidence of hypertension at 15.4% and prehypertension at 31.7%. Occurrence of hypertension and prehypertension in cases living as hikikomori >6 months were 3 times and 1.5 times higher than those newly onset cases, respectively. The blood pressure levels were correlated with age and all obesity index parameters measured including waist circumference and body mass index. Results also observed a shift of body weight from underweight to overweight and obesity along the hikikomori duration. Half of the hypertensive cases involved the elevation of systolic blood pressure, which suggested higher odds of cardiovascular complications. In conclusion, the hikikomori lifestyle could be a risk behavior that may harm the younger generation physically by promoting obesity and hypertension and probably other chronic illnesses., Competing Interests: The authors declare no conflict of interest.

Background: Poor social interactions have been recognized as a symptom since the beginnings of psychiatry. As far as socially withdrawn youth (SWY) are concerned, studies were mostly conducted on patients seeking care. Our psychiatric outreach team called Psymobile was able to reach SWY patients who were not seeking mental health care., Aims: To identify the clinical and socio-demographic characteristics of SWY patients referred to our Psymobile unit., Method: We carried out a retrospective study on the records of patients aged 18-34 years, who were referred to Psymobile for 'withdrawal', between April 2012 and December 2015., Results: In total, 66 patients were included in the study. SWY are predominantly male (80%) from large families or single-parent ones. About 42% had no prior contact with a mental health professional before being referred to Psymobile. The mean duration of withdrawal is 29 months. In all, 42% of SWY use cannabis and 73% present disorders of the sleep-wake schedule. About 71% maintain relations with their families and 73% go out occasionally. They are mostly diagnosed with schizophrenia (37%) or mood disorders (23%)., Conclusion: Over one-third of Psymobile patients aged 18-34 years were referred on grounds of social withdrawal. Our data may illustrate more accurately the situation of youth social withdrawal amid the general population than data from help-seeking patients or online questionnaires.

Hikikomori, often glossed as "social withdrawal," emerged as a sociomedical condition among Japanese youth at the end of the twentieth century, and it continues to fascinate and concern the public. Explanatory frameworks for hikikomori abound, with different stakeholders attributing it to individual psychopathology, poor parenting, and/or a lack of social support structures. This article takes an interpretive approach to hikikomori by exploring parents' narrative constructions of hikikomori children in support group meetings and in-depth interviews. I argue that some parents were able to find hope in hikikomori by 'emplotting' their children's experiences into a larger narrative about onset, withdrawal, and recovery, which helped them remain invested in the present by maintaining a sense of possibility about the future. Contrary to literature that examines hikikomori as an epidemic of isolated individuals, I demonstrate how parents play a key role in hikikomori through meaning-making activities that have the potential to shape their children's experiences of withdrawal.

This study examines the relationship between negative experiences, negative emotions, and delinquent behavior among young people in a social withdrawal situation. There were 533 participants in this study and various quantitative analyses were utilized. Results showed that participants with a longer period of social withdrawal were generally less affected by negative experiences, while those with a higher level of social withdrawal were more affected by negative experiences, particularly negative relationships with other people. Also, both negative emotions and higher level of social withdrawal mediated the relationship between negative experiences and involvement in delinquent behavior, with negative emotions displaying a higher mediating effect. This reflects that the root of delinquent behavior is the negative experiences which arouse negative emotions, rather than the social withdrawal behavior itself. Results imply that practitioners should first explore the negative experiences suffered by these young people, so as to provide them the most appropriate support., (Copyright © 2016 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.)

The study of social withdrawal subtypes is no longer limited to Western societies but has extended to non-Western countries, such as China. This study considers, for the first time, social withdrawal subtypes in an African country (Nigeria) by examining emerging adults' (N = 151; 54% female; Mage = 19.92 years, SD = 2.54) perceptions, attitudes, and responses to shy, unsociable, and socially competent behaviors. Results revealed that Nigerian emerging adults perceived significant differences between shy, unsociable, and socially competent behavior in several ways incommensurate with participants of previous studies conducted in North America, Europe, and China. Findings highlight the diversity of social meanings attached to social withdrawal in non-Western societies, and point to the need for additional research on social withdrawal and its perception in Africa., (Copyright © 2015 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.)

Background: Social withdrawal behaviour is a major health problem that is becoming increasingly important, being necessary studies that investigate its psychopathology and existence in different cultures., Aims: To describe the clinical and socio-demographic characteristics of hikikomori individuals in Spain., Method: Participants were 200 subjects referred to the Crisis Resolution Home Treatment (CRHT) because of social isolation. The definition of hikikomori was the state of avoiding social engagement with generally persistent withdrawal into one's residence for at least 6 months. Socio-demographic and clinical data were analysed, including Severity of Psychiatric Illness (SPI), Global Assessment of Functioning (GAF), Clinical Global Impression (CGI) and World Health Organization Disability Assessment (WHODAS) scales., Results: A total of 164 cases were evaluated. Hikikomori were predominantly young male, with the mean age at onset of hikikomori of 40 years old and a mean socially withdrawn period of 3 years. Only three people had no symptoms suggestive of mental disorder. Psychotic and anxiety were the most common comorbid disorders. The scales administered describe the presence of serious symptoms and impairment in social functioning, with a high prevalence of poor collaboration with treatment., Conclusion: This study shows the existence of hikikomori in Spain. Its difficult detection and treatment highlights the need for specialized domiciliary teams. The high comorbidity leads us to conclude that it may not be a new diagnosis, but rather a severe syndrome associated with multiple mental illnesses. Primary hikikomori also exist, but less commonly. Future cross-national studies are needed in order to describe its definition and psychopathology., (© The Author(s) 2014.)

Ding et al. (Brit. J. Dev. Psychol., 2015; 33, 159-173) demonstrated that Chinese children discriminate between the three subtypes of social withdrawal: Shyness, unsociability, and social avoidance. This commentary on the Ding et al.'s paper highlights the need to further explore the following: (1) children's understanding of the implications of being shy, unsociable, or socially avoidant, including assessing these which we know are associated with outcomes for socially withdrawn children; (2) what additional subtypes might exist naturally within the Chinese culture; and (3) consider the implications of social withdrawal on children's developing social skills., (© 2015 The British Psychological Society.)

The goal of this study was to examine young Chinese children's beliefs about the implications of different subtypes of social withdrawal (e.g., shyness, unsociability), including for the first time, social avoidance. Participants were 133 children in kindergarten (n = 58, Mage  = 70.85 months) and grade 1 (n = 75, Mage  = 83.49 months). Children were presented with vignettes describing hypothetical peers displaying shy, unsociable, avoidant, and socially competent behaviours and were then asked a series of questions to assess their beliefs about the implications of these different behaviours. Young children made distinctions between social withdrawal subtypes in terms of underlying motivations and emotions. Children also appeared to hold differential beliefs about the implications of different forms of social withdrawal: Of note, they anticipated that socially avoidant peers would experience the most negative outcomes. These findings provide some of the first evidence to suggest that social avoidance represents a distinct form of social withdrawal among young Chinese children. Results are discussed in terms of the importance of distinguishing between different subtypes of social withdrawal in Chinese culture., (© 2015 The British Psychological Society.)

In this commentary on Ding et al. (Brit. J. Dev. Psychol., 2015; 33, 159-173), we focus on the following: (1) the authors' use of vignettes portraying various prototypes of withdrawn children and (2) the cultural interpretation of their findings. We end with some suggestions for future research., (© 2015 The British Psychological Society.)

In this reply to the commentaries by Xinyin Chen, Charissa Cheah, Yiyuan Xu, and Dawn Watling, we further discuss the conceptual and methodological challenges that arise when attempting to study beliefs about social withdrawal (1) in the unique cultural context of China and (2) in the unique developmental age period of early childhood., (© 2015 The British Psychological Society.)

Aims: Hikikomori is a new psychosociological phenomenon among youth, of almost complete withdrawal from social interaction, and it has received considerable attention in community mental health in Japan. The aims of the present study were to identify the influential factors of family difficulties of parents who use support services for children with hikikomori, and compare them between fathers and mothers., Methods: Data were collected from 110 parents (55 couples) of children with hikikomori with regard to family difficulties, quality of life, and depression variables via self-report questionnaires. To assess the influential factors of Family Difficulties for parents with children with hikikomori, hierarchical multiple linear regression analysis was carried out for gender., Results: While 94.5% of mothers received some kind of family support, only 61.9% of fathers received it. For both genders, the number of services that the fathers received was significantly correlated with marital cooperation, and the number of services that the mothers received was significantly correlated with support resource utilization., Conclusions: It is necessary for fathers to receive more support, and it is important for professionals to encourage parents to address their difficulties together., (© 2014 The Authors. Psychiatry and Clinical Neurosciences © 2014 Japanese Society of Psychiatry and Neurology.)

Background: The Japanese term hikikomori means literally 'to be confined'. Social withdrawal can be present in severe psychiatric disorders; however, in Japan, hikikomori is a defined nosologic entity. There have been only a few reported cases in occidental culture., Material: We present a case report of a Spanish man with prolonged social withdrawal lasting for 4 years., Discussion: This is a case of prolonged social withdrawal not bound to culture, as well as the second case of hikikomori reported in Spain. We propose prolonged social withdrawal disorder as a disorder not linked to culture, in contrast to hikikomori., Conclusion: Further documentation of this disorder is still needed to encompass all cases reported in Japan and around the world., (© The Author(s) 2013.)