Shared genetics linking sociability with the brain's default mode network.

The brain's default mode network (DMN) plays a role in social cognition, with altered DMN function being associated with social impairments across various neuropsychiatric disorders. In the present study, we examined the genetic relationship between sociability and DMN-related resting-state functional magnetic resonance imaging (rs-fMRI) traits. To this end, we used genome-wide association summary statistics for sociability and 31 activity and 64 connectivity DMN-related rs-fMRI traits (N=34,691-342,461). First, we examined global and local genetic correlations between sociability and the rs-fMRI traits. Second, to assess putatively causal relationships between the traits, we conducted bi-directional Mendelian randomisation (MR) analyses. Finally, we prioritised genes influencing both sociability and rs-fMRI traits by combining three methods: gene-expression eQTL MR analyses, the CELLECT framework using single-nucleus RNA-seq data, and network propagation in the context of a protein-protein interaction network. Significant local genetic correlations were found between sociability and two rs-fMRI traits, one representing spontaneous activity within the temporal cortex, the other representing connectivity between the frontal/cingulate and angular/temporal cortices. Sociability affected 12 rs-fMRI traits when allowing for weakly correlated genetic instruments. Combing all three methods for gene prioritisation, we defined 17 highly prioritised genes, with DRD2 and LINGO1 showing the most robust evidence across all analyses. By integrating genetic and transcriptomics data, our gene prioritisation strategy may serve as a blueprint for future studies. The prioritised genes could be explored as potential biomarkers for social dysfunction in the context of neuropsychiatric disorders and as drug target genes.

Case report: hikikomori syndrome in Italy and its link with autistic traits and internet gaming disorder.

During the last few decades, a growing field of literature is focusing on hikikomori, a phenomenon described as a form of pathological social withdrawal or social isolation that lasts for more than 6 months leading to significant functional impairment and/or distress. Despite initially considered a culture-bound syndrome, hikikomori syndrome later gained a wider recognition in different countries, ranging from an attempt to take refuge in an idealistic world, when society success' standards are not reached, to a maladaptive coping strategy complicating several psychiatric illnesses such as anxiety disorders, major depression, internet addiction, internet gaming disorder (IGD) and autism spectrum disorder (ASD). In this framework, difficulties in social interaction, in problem solving strategies and socio-emotional reciprocity, may lead to social withdrawal and hikikomori-like behaviors. In this work, we described two cases of patients where the presence of underlying autism spectrum may have represented a sign of vulnerability towards the development of a possible full-blown case of hikikomori with IGD.

Validation of the German version of the 25-item hikikomori questionnaire 25.

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.

Forensic Characteristics of Body Abandonment by Housemates in Japan.

INTRODUCTION:  In Japan, many cases occur wherein housemates fail to report dead bodies found in their homes. However, only individual cases are reported through press and court records, and analysis including unreported cases has not been conducted. In this study, we evaluated cases handled by our Forensic Science Department in which housemates did not immediately report a dead body found in their home. We analyzed the overall picture and forensic characteristics of such cases, stratifying whether the abandoners were estimated hikikomori. METHODS:  Of the 1,179 legal autopsy cases handled by the Department of Forensic Medicine of Tokai University from January 1, 2017, to July 1, 2023, we evaluated 45 cases in which housemates did not immediately report dead bodies. The characteristics analyzed were body age, cause of death, autopsy findings, duration from the body's discovery by the abandoner to the police report, the reason for the lack of report in the first body discovery by the abandoner, and the reason for the report. In this study, the criteria for estimating whether a hikikomori abandoned the body were (1) the police provided the information that the person was a hikikomori or (2) the person met the following four criteria: 20-64 years old, unemployed, not in school, and living with parents. RESULTS:  Positive significant differences were found in the body's decomposition and the time from the body's discovery to the report to the police when the abandoner was suspected to be a hikikomori for more than one, four, or eight days. No significant differences were found in the cause of death. Regarding the reported characteristics, when the abandoner was an estimated hikikomori, positive and significant differences were found for recognizing the body and did not report immediately due to shock. Conversely, negative and significant differences were found for the person who reported as the abandoner. CONCLUSION:  This is the first study that reports on body abandonment by housemates and elaborates on its complications to forensic doctors. The incidence rate of abandonment is higher than expected. This study suggests that hikikomori are more likely to hide the bodies for longer, which hinders the death cause investigation.

The relationship between social withdrawal and problematic social media use in Chinese college students: a chain mediation of alexithymia and negative body image.

This study explores the relationship between social withdrawal and problematic social media use among college students, with a focus on the mediating roles of alexithymia and negative body image. Using the University Student Social Withdrawal Questionnaire, Social Media Addiction Scale, Toronto Alexithymia Scale, and Negative Body Image Scale, 2582 college students (33.46% male, average age = 19.46 years, SD = 2.23) were surveyed. Social withdrawal, alexithymia, negative body image, and problematic social media use were significantly correlated with each other. Social withdrawal positively predicted problematic social media use, and both alexithymia and negative body image played a chain mediating role between social withdrawal and problematic social media use. The findings indicate that individual social withdrawal is associated with college students' problematic use of social media. The results suggest that alexithymia and negative body image may mediate this association, highlighting a potential pathway through which social withdrawal influences social media use patterns.

Corrigendum: Reevaluating hikikomori and challenging loneliness assumptions in Japan: A cross-sectional analysis of a nationwide internet sample.

[This corrects the article DOI: 10.3389/fpsyt.2024.1323846.].

Aggressive and Withdrawn Behaviour at School through the Lens of Teachers and Peers: A Qualitative Study.

We explored teachers' understanding of children with aggressive or socially withdrawn behaviour in their classes and we associated our findings with a status of rejected, neglected, or popular, as provided by peer nominations. Five kindergarten and elementary school teachers scored their 143 pupils with the Child Behaviour Checklist for Withdrawal and Aggression. Subsequently, only those children whose scores were 1 standard deviation above the mean for withdrawal or for aggression were included in the final sample (n = 46; Mage = 6.5 years, SD = 1.7; age range = 4-9 years). The final sample included 31 children (21.67%; females = 16) who were assessed as displaying withdrawn behaviour, and 15 (10.48%; females = 5) displaying aggressive behaviour. An open-ended semi-structured interview was administered to teachers, who described children with socially withdrawn behaviour as introverted and untalkative, children with aggressive behaviour as hostile, rule-breaking and highly active, and children with socially withdrawn or aggressive behaviour as isolated, even though different reasons were provided. The results of the sociometric status in children with socially withdrawn or aggressive behaviour are discussed.

Social skill and social withdrawal outcomes in children following pediatric stroke.

Pediatric stroke can result in long-term impairments across attention, functional communication and motor domains. The current paper utilized parent reports of the Behavioral Assessment System for Children 2nd Edition and the Pediatric Stroke Outcome Measure to examine children's social skills and withdrawal behavior within a pediatric stroke population. Using the Canadian Pediatric Stroke Registry at The Hospital for Sick Children, data were analyzed for 312 children with ischemic stroke. Children with ischemic stroke demonstrated elevated parent-reported social skills problems (observed = 20.51%, expected = 14.00%) and clinically elevated social withdrawal (observed = 11.21%, expected = 2.00%). Attentional problems significantly contributed to reduced social skills, F (3,164) = 30.68, p < 0.01, while attentional problems and neurological impairments accounted for increased withdrawal behavior, F (2, 164) = 7.47, p < 0.01. The presence of a motor impairment was associated with higher social withdrawal compared to individuals with no motor impairment diagnosis, t(307.73) = 2.25, p < .025, d = 0.25, 95% CI [0.42, 6.21]. The current study demonstrates that children with stroke who experience motor impairments, attentional problems, reduced functional communication skills, and neurological impairments can experience deficits in their social skills and withdrawal behavior.

Perception of unfamiliar caregivers during sickness - Using the new Caregiver Perception Task (CgPT) during experimental endotoxemia.

Social withdrawal is a well-established part of sickness behavior, but in some contexts sick animals might gain from keeping close instead of keeping away. For instance, sick individuals are more willing to be near known individuals who can provide care and safety (close others) compared to when healthy. Yet, interactions with some strangers might also be beneficial (i.e., healthcare professionals), but it is not known how sickness interplay with social behavior towards such individuals. Here, we assessed if sickness affects perception of caregivers, and developed a new task, the Caregiver Perception Task (CgPT). Twenty-six participants performed the CgPT, once after an injection of lipopolysaccharide (LPS, 0.8 ng/kg body weight, n = 24), and once after an injection of saline (n = 25), one hour and forty-five minutes post-injection. During the task, participants watched short video clips of three types of caregivers: a healthcare professional taking care of a sick individual, a healthcare professional not taking care of a sick individual, and a non-healthcare professional taking care of their sick adult child or partner. After each video clip, the likability, trustworthiness, professionalism, and willingness to interact with and receive care from the caregiver were rated on visual analogue scales. Results showed that participants injected with saline rated healthcare professionals who did not take care of a sick individual less positively on all aspects compared to healthcare professionals who took care of a sick individual. Moreover, compared to saline, LPS increased the participants' willingness to receive care from healthcare professionals and non-healthcare professionals providing care, but not from healthcare professionals not providing care. Thus, our results indicate that sick individuals may approach unknown individuals with potential to provide care and support.

Social withdrawal behaviour in Nepalese infants and the relationship with future neurodevelopment; a longitudinal cohort study.

BACKGROUND: Social withdrawal in infants may be a signal of distress and a precursor for non-optimal development. OBJECTIVE: To examine the relationship between infant social withdrawal and neurodevelopment up to 4 years in Nepalese children. METHODS: A total of 597 Nepalese infants 6-11 months old were assessed with the modified Alarm Distress Baby Scale (m-ADBB), and of these, 527 with the Bayley Scales of Infant and Toddler Development 3rd edition (Bayley-III) during early childhood, and the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-IV) and NEPSY-II subtests at 4 years. We examined whether social withdrawal defined by the m-ADBB was associated with neurodevelopmental scores in regression models. RESULTS: Children socially withdrawn in infancy had lower Bayley-III language scores (-2.6 (95% CI -4.5, -0.7)) in early childhood. This association seems to be driven by the expressive communication subscale (-0.7 (95% CI -1.0, -0.3)), but not the receptive communication subscale (-0.2 (95% CI -0.6, 0.1)). There were no differences in the other Bayley-III scores or the WPPSI-IV and NEPSY-II scores at 4 years in children who were socially withdrawn or not. CONCLUSION: Social withdrawal in infancy was reflected in early language development but not cognitive functioning at 4 years.

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.

Reevaluating hikikomori and challenging loneliness assumptions in Japan: A cross-sectional analysis of a nationwide internet sample.

Introduction: Loneliness in Japan, accentuated by demographic challenges and the hikikomori phenomenon (extreme social withdrawal), has raised concerns. This study critically examines loneliness dynamics, questioning assumptions embedded in hikikomori classifications. The term "hikikomori," originally signifying prolonged home stay, requires nuanced exploration, especially regarding outgoing behaviors' relationship with loneliness. Objectives: Investigating the intricate connection between outgoing behaviors and loneliness, this study questions the effectiveness of existing hikikomori classifications. Aiming to understand if these classifications accurately represent the loneliness spectrum across age groups, the research emphasizes the significance of comprehending loneliness dynamics amid societal challenges. The study explores an array of factors influencing loneliness, including demographics, mental health, and outgoing behaviors, advocating for a reassessment of assumptions linked to hikikomori classifications. Methods: This secondary analysis employed data from a nationwide Internet addiction survey conducted in July 2012. A sample of 623 participants, representative of Japanese internet users aged 16 and above, underwent factor analysis. Loneliness was assessed using the UCLA Loneliness Scale, and exposure variables included demographic, mental health, outgoing behaviors, and lifestyle factors. Statistical analyses encompassed descriptive statistics, one-way ANOVA, chi-square tests, and logistic regression. Results: Significant differences were observed in loneliness scores based on sex, age, marital status, employment, and outgoing behaviors. Mental health factors, including dissatisfaction with life and romance, life stress, and psychological distress, emerged as strong contributors to loneliness. The study challenges existing hikikomori classifications, suggesting they may not fully encapsulate the loneliness experiences of individuals engaged in routine school or work activities. Conclusion: Findings underscore the need for a reevaluation of hikikomori, emphasizing loneliness as a complex and multifaceted issue in Japan. The study advocates for nuanced strategies to address loneliness, considering diverse demographic vulnerabilities. Limitations include the pre-pandemic sample and potential unmeasured confounding factors.

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.

Autism traits, social withdrawal, and behavioral and emotional problems in a Norwegian cohort of adolescents with rare genetic disorders.

BACKGROUND: Adolescents with rare genetic disorders represent a population that can be at risk in psychosocial terms. Despite its importance, the association of autism traits and social withdrawal in behavioral and emotional problems in adolescents with rare genetic disorders remains understudied. AIM: The study aimed to empirically examine the clinical characteristics of adolescents with rare genetic disorders with a behavior theory-driven approach. METHOD: We investigated the behavioral and emotional problems and current and lifetime autistic traits in a sample of 93 Norwegian adolescents (Mage = 13.2 years, SDage = 2.4, rangeage 10-17, 62.4% females, 37.6% males) with various rare genetic disorders. The adolescents were investigated cross-sectionally utilizing standardized psychometric questionnaires rated by their parents. RESULTS: More current and lifetime autistic traits and social withdrawal were all associated with more internalizing problems. Further analyses demonstrated that social withdrawal partially mediated the positive association between current autistic traits and internalizing problems. In contrast, social withdrawal fully mediated the positive association between lifetime autistic traits and internalizing problems. CONCLUSION AND IMPLICATIONS: Our results demonstrate important characteristics of adolescents with rare genetic disorders that may guide clinicians and future interventions. Social withdrawal may be prodromal to internalizing problems such as anxiety and depression. Thus, clinically addressing social withdrawal can represent a means to prevent internalizing problems in adolescents with rare genetic disorders and autistic traits.

Reciprocal longitudinal effects among Korean young adolescent' negative peer relationships, social withdrawal, and smartphone dependence.

The research should consider the complex dynamics of social interaction to better understand smartphone dependence among adolescents. In social situations, adolescents can choose to interact with their peers or use their smartphones, and smartphone dependence can drive adolescents far away from interaction with their peers. Adolescents, conversely, may use smartphones to avoid peer interaction because they have experienced social withdrawal or negative peer relationships. Previous research has not discussed enough what precedes or follows in longitudinal relationships. This study aims to examine the reciprocal longitudinal effects between adolescents' negative peer relationships, social withdrawal, and smartphone dependence. The analysis used longitudinal panel data collected yearly between 2018 and 2020 from the Korean Children and Youth Panel Survey (KCYPS) sampled from adolescents in the Republic of Korea and employed autoregressive cross-lagged modeling on 2230 participants. The reciprocal longitudinal relationships differed depending on the sub-factors of smartphone dependence. For instance, the sub-factor of smartphone dependence, including virtual life orientation and withdrawal, had reciprocal longitudinal relationships with negative peer relationships. The other sub-factor of smartphone dependence, including daily life disturbance and tolerance, influenced negative peer relationships consistently, but the converse path did not. In addition, social withdrawal longitudinally affected negative peer relationships the following year. However, the reciprocal longitudinal relationships between social withdrawal and smartphone dependence were not significant in any path in this research. This research provides practical implications for intervention to reduce smartphone dependence among young adolescents.

Association between social withdrawal and suicidal ideation in patients with major depressive disorder: The mediational role of emotional symptoms.

BACKGROUND: The study was designed to investigate the associations between social withdrawal, emotional symptoms, and suicide ideation in patients with major depressive disorder (MDD). METHODS: This cross-sectional study included 2678 MDD patients from the National Survey on Symptomatology of Depression (NSSD). Differences in the sociodemographic factors, clinical characteristics, suicide ideation, and emotional symptoms were compared in patients with different frequencies of social withdrawal. Pearson correlation, multiple linear regression analysis, and mediation analysis were employed to assess the contribution of social withdrawal to suicide ideation. RESULTS: MDD patients with a higher frequency of social withdrawal were prone to have a higher frequency of suicide ideation (p for trend <0.001) and history of suicide behavior (p for trend <0.001). Multiple linear regression analysis showed that there was a dose-response relationship between social withdrawal and suicide ideation in MDD patients, but this association became insignificant after adjusting for emotional symptoms. Mediation analysis suggested that all of the emotional symptoms had significant mediating effects on the association between social withdrawal and suicide ideation in MDD patients (p < 0.05). The magnitude of mediation varied between 4.3 % and 64.3 %, with the largest mediating effect in the feeling of despair (64.3 %), helplessness (41.2 %), and loneliness (40.0 %). CONCLUSION: Our study provides evidence that social withdrawal was a common clinical presentation and it may increase the risk for suicide through emotional symptoms in MDD patients. LIMITATIONS: Causal conclusions could not be drawn between social withdrawal, emotional symptoms, and suicide ideation because of the cross-sectional design of the study.

Pro-social and pro-cognitive effects of LIT-001, a novel oxytocin receptor agonist in a neurodevelopmental model of schizophrenia.

Social and cognitive dysfunctions are the most persistent symptoms of schizophrenia. Since oxytocin (OXT) is known to play a role in social functions and modulates cognitive processes, we investigated the effects of a novel, nonpeptide, selective OXT receptor agonist, LIT-001, in a neurodevelopmental model of schizophrenia. Administration of methylazoxymethanol acetate (MAM; 22 mg/kg) on the 17th day of rat pregnancy is known to cause developmental disturbances of the brain, which lead to schizophrenia-like symptomatology in the offspring. Here, we examined the effects of acutely administered LIT-001 (1, 3, and 10 mg/kg) in MAM-exposed males and females on social behaviour, communication and cognition. We report that MAM-treated adult male and female rats displayed reduced social behaviour, ultrasonic communication and novel object recognition test performance. LIT-001 partially reversed these deficits, increasing the total social interaction time and the number of 'positive', highly-modulated 50 kHz ultrasonic calls in male rats. The compound ameliorated MAM-induced deficits in object discrimination in both sexes. Present results confirm the pro-social activity of LIT-001 and demonstrate its pro-cognitive effects following acute administration.

The relationship between addiction and hikikomori tendencies: a case-control study.

Aim: The present study examined the relationship between addiction and hikikomori (extreme social withdrawal) symptoms. Method: A group of clinically referred addiction patients (n = 31) and a group of age- and gender-matched non-clinical controls (n = 34) completed a self-report scale for measuring hikikomori symptoms (the Hikikomori Questionnaire-25) along with some other questionnaires assessing substance use (frequency and severity) and quality of life. Results: The results showed that addiction patients displayed significantly higher levels of hikikomori symptoms than the non-clinical control (Cohen's d = 3.41); 87.1% even showed such a high score that they were identified as being at risk for the hikikomori syndrome (vs. only 2.9% in the non-clinical control group). Correlational analyses revealed that within the addiction group, the severity of the substance use problem (as quantified by an index of craving) correlated positively with the level of hikikomori symptoms and negatively with quality of life. In other words, the more severe the addiction, the more extreme the social withdrawal tendencies and the lower the quality of life. Conclusion: Altogether, the findings provide further support for the marked social impairments of people with substance use problems and underline that this should be an important target of intervention.