Analysis of the hikikomori phenomenon - an international infodemiology study of Twitter data in Portuguese.

BACKGROUND: Hikikomori refers to the extreme isolation of individuals in their own homes, lasting at least six months. In recent years social isolation has become an important clinical, social, and public health problem, with increased awareness of hikikomori around the globe. Portuguese is one of the six most spoken languages in the world, but no studies have analysed the content regarding this phenomenon expressed in Portuguese. OBJECTIVE: To explore the hikikomori phenomenon on Twitter in Portuguese, utilising a mixed-methods approach encompassing content analysis, emotional analysis, and correlation analysis. METHODS: A mixed methods analysis of all publicly available tweets in the Portuguese language using a specific keyword (hikikomori) between 1st January 2008 and 19th October 2022. The content analysis involved categorising tweets based on tone, content, and user types, while correlation analysis was used to investigate user engagement and geographical distribution. Statistical analysis and artificial intelligence were employed to classify and interpret the tweet data. RESULTS: Among the total of 13,915 tweets generated, in terms of tone 10,731 were classified as "negative", and 3184 as "positive". Regarding content, "curiosities" was the most posted, as well as the most retweeted and liked topic. Worldwide, most of the hikikomori related tweets in Portuguese were posted in Europe, while "individuals with hikikomori" were the users most active posting. Regarding emotion analysis, the majority of tweets were "neutral". CONCLUSIONS: These findings show the global prevalence of the discourse on hikikomori phenomenon among Portuguese speakers. It also indicates an increase in the number of tweets on this topic in certain continents over the years. These findings can contribute to developing specific interventions, support networks, and awareness-raising campaigns for affected individuals.

Predominant affective temperaments in depressive patients with severe social withdrawal.

BACKGROUND: Hikikomori (HK) is characterized by self-isolation and social refusal, being more likely also associated with affective disorders, including depression. This case-control study primarily aimed at identifying (if any) predominant affective temperaments are associated with HK in depressed versus not-depressed individuals. Secondary objectives comprise assessing which other psychopathological dimensions (e.g., boredom, anxiety) are associated with the HK specifier in depressed individuals. METHODS: From the larger SWATCH study, 687 Italian young people were screened for depression, as measured by 9 items-Patient Health Questionnaire (PHQ-9) and HK-like social withdrawal, through the Hikikomori Questionnaire-25 (HQ-25). All subjects were administered a brief-Temperament Evaluation of Memphis, Pisa, Paris and San Diego (TEMPS-M), the 7 items-Generalized Anxiety Disorder (GAD-7) and the Multidimensional State Boredom Scale (MSBS). RESULTS: Males reported significantly higher scores at HQ-25 total score than females (p = 0.026). In the total sample, HK social withdrawal is positively predicted by MSBS low arousal, disengagement, depressive levels, depressive and irritable affective temperaments, while negatively by anxiety (F(6, 680) = 82.336, p < 0.001, R2 = 0.421). By selecting only depressed sample, HQ-25 is positively predicted by MSBS total score, low arousal and depressive affective temperament, while negatively by MSBS high arousal (F(4, 383) = 48.544, p < 0.001, R2 = 0.336). The logistic regression model found that the likelihood of developing depression with the HK specifier is significantly predicted by depressive and cyclothymic affective temperaments. CONCLUSIONS: These preliminary findings could help in clinically characterizing the relationship between specific affective temperamental profiles among individuals with depression with/without HK specifier, in order to provide a more tailored and personalized therapeutic approach. Our Italian study should be extensively replicated in larger, longitudinal and multicentric pan-European studies, by specifically assessing the impact of these findings on depression clinical course, prognosis and treatment outcomes.

Hikikomori: A perspective from bibliometric analysis.

AIMS: Hikikomori is a common phenomenon reported in Japan and many other countries. However, the broad trends of the research publications on hikikomori are unclear. Therefore, this study examined the patterns of research on hikikomori using bibliometric analysis. METHODS: Relevant publications were searched in Web of Science. Bibliometric analyses were performed with CiteSpace, R and VOSviewer. RESULTS: In total, 297 publications on hikikomori met the eligibility criteria. The International Journal of Social Psychiatry (IF = 10.461) published the most papers (K = 17, or 5.7%) on hikikomori. Takahiro A. Kato from Kyushu University (41; 13.8%; H-index = 18) was the most influential author, while Takahiro A. Kato (total link strength [TLS]: 235), Alan R. Teo (TLS: 157), and Masaru Tateno (TLS: 153) separately had the strongest research collaboration with other researchers. Of all countries that published on hikikomori, Japan had the highest number of publications (K = 91). The keywords "United States" and "psychiatric diagnosis" received the most attention between 2013 and 2015, whereas "health" and "autism spectrum disorder" received the most attention in 2021 and 2022. CONCLUSIONS: Peer-reviewed research publications on hikikomori are growing rapidly and the research trends in this field are also changing.

Prolonged Social Withdrawal During Adolescence: Transdiagnostic Syndrome or a New Psychiatric Entity?

The Japanese term Hikikomori is used to describe a clinical condition in which young people present a prolonged social withdrawal and isolation. Hikikomori syndrome represents an emergent worldwide phenomenon but is still poorly reported and often misdiagnosed. This study investigates and describes an Italian hikikomori adolescent group. Socio-demographic and psychopathological profiles and the relationship between hikikomori and psychopathological conditions were analyzed. No gender difference, a medium-high intellectual level, and no correlation with socioeconomic status were highlighted among the clinical group. The relationship between social withdrawal and social anxiety was significant while no correlation was found with depressive symptoms. The presence of Hikikomori syndrome was also significant in Italian adolescents, suggesting that hikikomori is not a culture-bound syndrome related to the Japanese cultural context, but rather a syndrome occurring in the upper-medium class.

Validation of the Italian version of the 25-item Hikikomori Questionnaire (HQ-25-I).

INTRODUCTION: The present study aimed to adapt the 25-item Hikikomori Questionnaire to the Italian context (HQ-25-I) and to test its psychometric properties in two samples, particularly a sample of residents with psychiatric conditions (n = 117) and a sample of individuals from the community (n = 209). METHODS: We tested the fit of the original three-factor structure (Socialization, Isolation, and Emotional Support) and measurement invariance across the two groups, and the reliability, convergent, and criterion (concurrent) validity of the HQ-25-I. RESULTS: The results showed that the original measurement model fitted the data well and that it was invariant across the two groups. The measure was reliable and positively correlated with some maladaptive personality trait domains (PID-5-BF), Depression (BDI-II), and Hopelessness (BHS) in both groups, with higher scores observed in the clinical sample. However, low correlations were found between the HQ-25-I and the PID-5-BF Detachment and Negative Affectivity. CONCLUSIONS: The results from the study showed that the HQ-25-I is reliable, but further examination of its validity is warranted. Implications for theory and future research are discussed.

Evolution and trends of hikikomori: a bibliometrics analysis.

Hikikomori is the Japanese term for the phenomenon of young adults isolating themselves from society and becoming reclusive. This study aims to examine the evolution and distribution of hikikomori, as well as identify the major players and institutions involved in hikikomori research. The searches, which were conducted in Scopus database identified 286 academic research works pertaining to hikikomori research. The findings indicate that hikikomori has attracted the attention of academic researchers in both the East and the West, with a consistent increase in research output since the Internet revolution over the past decade. The study highlights the potential for additional research on hikikomori and provides a benchmark for new researchers entering the field.

Preliminary study of the social withdrawal (hikikomori) spectrum in French adolescents: focusing on the differences in pathology and related factors compared with Japanese adolescents.

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.

Who are hikikomori? Demographic and clinical features of hikikomori (prolonged social withdrawal): A systematic review.

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 (ß = 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.

Examining Tweet Content and Engagement of Users With Tweets About Hikikomori in Japanese: Mixed Methods Study of Social Withdrawal.

BACKGROUND: Hikikomori is a form of severe social withdrawal that is particularly prevalent in Japan. Social media posts offer insight into public perceptions of mental health conditions and may also inform strategies to identify, engage, and support hard-to-reach patient populations such as individuals affected by hikikomori. OBJECTIVE: In this study, we seek to identify the types of content on Twitter related to hikikomori in the Japanese language and to assess Twitter users' engagement with that content. METHODS: We conducted a mixed methods analysis of a random sample of 4940 Japanese tweets from February to August 2018 using a hashtag (#hikikomori). Qualitative content analysis included examination of the text of each tweet, development of a codebook, and categorization of tweets into relevant codes. For quantitative analysis (n=4859 tweets), we used bivariate and multivariate logistic regression models, adjusted for multiple comparisons, and estimated the predicted probabilities of tweets receiving engagement (likes or retweets). RESULTS: Our content analysis identified 9 codes relevant to tweets about hikikomori: personal anecdotes, social support, marketing, advice, stigma, educational opportunities, refuge (ibasho), employment opportunities, and medicine and science. Tweets about personal anecdotes were the most common (present in 2747/4859, 56.53% of the tweets), followed by social support (902/4859, 18.56%) and marketing (624/4859, 12.84%). In the adjusted models, tweets coded as stigma had a lower predicted probability of likes (-33 percentage points, 95% CI -42 to -23 percentage points; P<.001) and retweets (-11 percentage points, 95% CI -18 to -4 percentage points; P<.001), personal anecdotes had a lower predicted probability of retweets (-8 percentage points, 95% CI -14 to -3 percentage points; P=.002), marketing had a lower predicted probability of likes (-13 percentage points, 95% CI -21 to -6 percentage points; P<.001), and social support had a higher predicted probability of retweets (+15 percentage points, 95% CI 6-24 percentage points; P=.001), compared with all tweets without each of these codes. CONCLUSIONS: Japanese tweets about hikikomori reflect a unique array of topics, many of which have not been identified in prior research and vary in their likelihood of receiving engagement. Tweets often contain personal stories of hikikomori, suggesting the potential to identify individuals with hikikomori through Twitter.

[Challenges, prevention, and countermeasures for social withdrawal (hikikomori) by age group].

　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.

Risk factors of hikikomori among office workers during the COVID-19 pandemic: A prospective online survey.

The global pandemic of COVID-19 has forced people to restrict their outings. In Japan, self-restraint behavior (SRB) has been requested by the government, and some of those decreasing their outings may shift to pathological social withdrawal; hikikomori. The purpose of this study was to examine the risk factors of hikikomori conducting an online prospective survey. An online survey was conducted in June 2020 and December 2020; (1) SRB-related indicators (degree of SRB, motivation for SRB, stigma and self-stigma toward COVID-19, anxiety and depressive feelings toward COVID-19) and (2) general mental health (hikikomori tendency, depressive symptoms, modern type depression (MTD) tendency, internet addiction) were collected. A cross-lagged effects model was performed to examine the association between these variables. Lack of emotional support and lack of socialization in June 2020 increased isolation in December 2020. Besides, MTD and hikikomori interacted with each other. Interestingly, although hikikomori tendency increased depressive tendencies, SRB itself did not have a significant path on any mental health-related variables. Poor interpersonal relationships, rather than SRB per se, are suggested to be a risk factor for increased isolation among office workers in the COVID-19 pandemic. Appropriate early interventions such as interpersonal or emotional support may prevent the transition to pathological hikikomori. The association between MTD and hikikomori seems to reveal the interesting possibility that MTD is a gateway to increased risk of hikikomori, and that hikikomori is a gateway to MTD as well. Future research is required to elucidate the relationship between hikikomori and MTD.

A correlational study of socioeconomic factors and the prevalence of hikikomori in Japan from 2010 to 2019.

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.

Identifying Social Withdrawal (Hikikomori) Factors in Adolescents: Understanding the Hikikomori Spectrum.

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.

Psychodynamic group psychotherapy for hikikomori: The case of a socially withdrawn male with schizoaffective disorder.

Hikikomori, a severe form of social withdrawal, is a condition characterized by the avoidance of social participation and staying at home for more than 6 months. Hikikomori was initially reported in Japan in the 1990s and is now observed worldwide. Here, we introduce specialized psychodynamic group psychotherapy for persons with hikikomori, and illustrate the case of an adult male with schizoaffective disorder. In the present report, the patient initiated an unreasonably difficult job-hunting process, became unwell, and was hospitalized. He began to participate in group psychotherapy as a place of belonging and gradually increased his social interactions. We also consider the specific difficulties exhibited by people with hikikomori, especially focusing on the avoidance around assuming responsibility for decisions and extreme dichotomous thinking. Additionally, we discuss the benefits of dealing with these difficulties in a group structure and propose the applicability of group psychotherapy in therapeutic interventions for persons with hikikomori.

Hikikomori: psychopathology and differential diagnosis of a condition with epidemic diffusion.

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 Characteristics and Social Functioning of Pathological Social Withdrawal, "Hikikomori," in a Secondary Care Setting: a One-Year Cohort Study.

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.

Autism spectrum conditions in hikikomori: A pilot case-control study.

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.

Characteristics of and gender difference factors of hikikomori among the working-age population: A cross-sectional population study in rural Japan.

Objectives　This study aimed to assess the relevance of hikikomori to a variety of socio-demographic characteristics and socio-psychological conditions and examined these relationships by gender.Methods　The study employed a cross-sectional design. A questionnaire survey was conducted among 2,459 participants aged 15-64 years and living in Happo-cho, Akita. The outcome variable, hikikomori, was characterized by "not having participated in any social events nor interacted with others besides family members for more than six months." Exposure variables included sex, age, marital status, occupational status, outdoor frequencies, health, socio-psychological well-being, and availability of social support. Using Chi-square test of independence and multiple logistic regression, the results indicated the impact of the individual factors and the combined impact of all potential variables on the likelihood of being hikikomori in both participant groups: men and women.Results　The effective response rate was 54.5%. Those who socially withdrew for six months or more (n=164 (6.7%); 53.7% men, 46.2% women) were classified as being hikikomori; of these, 45.7% had been withdrawn for more than 10 years. Hikikomori men were more likely to have severe symptoms of mental illness, poorer overall self-rated health, feelings of distress, and passive suicidal ideation than non-hikikomori men, but not hikikomori women. Furthermore, after adjusting for all tested variables as possible confounding factors, being jobless and having fewer outdoor frequencies were associated with being a hikikomori man, and being a homemaker and having no social support were associated with being a hikikomori woman.Conclusion　Occupational status and outdoor frequencies are relevant factors for assessing the likelihood of being a hikikomori. Characteristics of hikikomori manifest differently in men and women. Having social support may help women avoid transitioning into a hikikomori. Incorporating emotional and mental health management into intervention programs may help better target potential beneficiaries among Japanese men.

Exploring the Extent of the Hikikomori Phenomenon on Twitter: Mixed Methods Study of Western Language Tweets.

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.

Hikikomori : Multidimensional understanding, assessment, and future international perspectives.

Hikikomori, a severe form of social withdrawal, has long been observed in Japan mainly among youth and adolescents since around the 1970s, and has been especially highlighted since the late 1990s. Moreover, hikikomori-like cases have recently been reported in many other countries. Hikikomori negatively influences not only the individual's mental health and social participation, but also wider education and workforce stability, and as such is a novel urgent global issue. In this review, we introduce the history, definition, diagnostic evaluation, and interventions for hikikomori and also the international prevalence of hikikomori outside Japan. We propose a hypothesis regarding the globalization of hikikomori based on domestic and international perspectives. In addition, we introduce our latest assessment system for hikikomori (including the latest version of the 'proposed diagnostic criteria of hikikomori for the future DSM/ICD diagnostic systems') and propose therapeutic strategies, including family approaches and individualized therapies. Finally, we present future challenges that may lead to solutions for an internationalized hikikomori.