The suitability of outing frequency as a definition of hikikomori (prolonged social withdrawal).

Recent research has employed outing frequency, referred to in this study as one's frequency of going out of the home, as a condition to define and determine the severity of hikikomori (prolonged social withdrawal). However, there is little definitive evidence on this topic. Furthermore, compared to the previous definition, it is unclear how the scope of hikikomori included in the proposed condition differs. This study aimed to clarify the relationship between hikikomori tendencies and the frequency and quality of outings to bridge this gap in research. Methods: Data included 397 self-rated online samples, 72 self-rated offline samples, and 784 parent-rated samples. Quantitative and qualitative indicators of outings and subjective social functioning impairment were used in the analysis. Results: The cut-off points supported the criteria for the number of days outside the home proposed in previous studies. The results revealed that the outing frequency condition excluded about 14.5-20.6% of those previously considered to have hikikomori. Logistic regression analysis showed that low outings with interpersonal interaction, low frequency of outings, and high subjective social functioning impairment consistently predicted hikikomori. However, outings without interpersonal interaction did not predict hikikomori. Conclusion: These results indicate that outing frequency tends to be suitable as one of the conditions for hikikomori. However, they indicate that we should also focus on the quality of outings, that is, outings with or without interpersonal interaction, to evaluate hikikomori consistently with previous findings. Further research is needed to clarify the appropriate frequency of outings to define hikikomori and determine its severity.

Measuring the Quality of Life for Individuals With Prolonged Social Withdrawal (Hikikomori).

OBJECTIVE: This study aimed to develop a quality of life scale for hikikomori (QOL-H), measuring the subjective quality of life (QOL) of individuals with hikikomori, and confirming its reliability and validity. METHODS: The characteristics of the scale were examined using item response theory. Data were collected from 99 people with hikikomori, 100 people who had experienced hikikomori in the past, and 198 people who had not experienced hikikomori, to develop the scale, examine its reliability, validity, and characteristics. For convergent validity, the correlation coefficients between QOL-H and social interaction behaviors, hikikomori characteristics, depressive symptoms, subjective happiness, and difficulty in social participation were calculated. RESULTS: Good internal consistency, test-retest reliability, and convergent validity were confirmed for the QOL-H. Furthermore, significant differences in scores among all groups confirmed adequate criterion-related validity. Total information function indicated a high measurement accuracy when QOL was average or slightly high. CONCLUSION: This study suggests that QOL-H can be an appropriate measure of QOL for individuals with 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.

3-day intervention program for family members of hikikomori sufferers: A pilot randomized controlled trial.

Backgrounds: Hikikomori, pathological social withdrawal, is becoming a crucial mental health issue in Japan and worldwide. We have developed a 3-day family intervention program for hikikomori sufferers based on Mental Health First Aid (MHFA) and Community Reinforcement and Family Training (CRAFT). This study aims to confirm the effectiveness of the 3-day program by a randomized controlled trial. Methods: This study was registered on the UMIN Clinical Trials Registry (UMIN000037289). Fifteen parents were assigned to the treat as usual (TAU) group (TAU only; Age Mean, 65.6; SD, 7.8), and 14 to the Program group (program + TAU; Age Mean, 67.9; SD, 8.6). This study was discontinued due to the COVID-19 pandemic; the recruitment rate was 36.3% of our target sample size of 80. Results: Perceived skills improved temporally and stigma temporally worsened in the TAU group. Confidence decreased and attitude showed no change in both groups. Aggressive behaviors of hikikomori sufferers were significantly worsened in the Program group; however, no serious domestic violence was reported. In the TAU group, Avoidance and irregular life patterns were improved. Activity levels were worsened in both groups. Two participants (16.7%) in the Program group and one participant (7.7%) in the TAU group reported actual behavioral changes (e.g., utilizing support). Conclusion: We could not draw general conclusions on the effectiveness of the program due to the study discontinuation. Nevertheless, this study indicates the necessity for revision of the program to improve family members' confidence in engaging with hikikomori sufferers, with safer approaching by families.

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.

Psychological Factors Associated with Social Withdrawal (Hikikomori).

OBJECTIVE: Cases of prolonged social withdrawal (hikikomori) have recently been reported in several countries. This study examined the impact of cognitive-behavioral and emotional factors on hikikomori behavior to identify intervention targets. Identifying such targets could facilitate the development of techniques to address hikikomori characteristics. METHODS: Two hundred Japanese individuals (mean age=38.73, SD=6.85) completed the Adaptive Behaviors Scale for Hikikomori and Stress Response Scale-18, along with the Japanese versions of the Self-Compassion Scale (Short Form), Acceptance and Action Questionnaire-II, and Brief Coping Orientation to Problems Experienced Inventory. Participants were divided into two groups: individuals with no experience of social withdrawal, and those with experience of social withdrawal. RESULTS: Hierarchical multiple regression analysis showed that the use of instrumental support, behavioral disengagement stress coping skills, self-compassion, and psychological stress were associated with hikikomori behaviors. Furthermore, higher instrumental support levels, associated with a decrease in hikikomori behaviors, were found in the hikikomori group. CONCLUSION: The use of instrumental support, behavioral disengagement stress coping skills, self-compassion, and psychological stress should be targeted in hikikomori prevention interventions. Moreover, encouragement for the use of instrumental support is needed for improving hikikomori.

Validation of the Japanese version of the Sleep Hygiene Practice Scale.

OBJECTIVE: This study sought to validate the Japanese version of the Sleep Hygiene Practices Scale (SHPS-J). PATIENTS/METHODS: A cross-sectional questionnaire-based study was conducted via the internet. In total, 854 participants (435 men, 419 women; mean age, 42.91 ± 11.54 years) were asked to complete all scales, and 283 of them were asked to complete the same scales two weeks later. The survey consisted of the SHPS-J, the Japanese version of the Insomnia Severity Index (ISI-J), and the Japanese version of the Pittsburgh Sleep Quality Index (PSQI-J). The SHPS-J was developed according to the International Society for Pharmacoeconomics and Outcomes Research Task Force for Translation and Cultural Adaption. For the analysis, participants were divided into three groups: insomnia syndrome, insomnia symptoms, and good sleep groups. RESULTS: The SHPS-J had good test-retest reliability (ICC: 0.55-0.76) and adequate internal consistency (α = 0.54-0.74), except with regard to eating/drinking behaviors. The factorial validity of the four-factor structure was confirmed through a confirmatory factor analysis; however, one item related to eating/drinking behaviors had no significant factor loading. The construct validity was confirmed through a correlation analysis between each domain of the SHPS-J and ISI-J (r = 0.19-0.60, p < 0.01). The results of clinical validation confirmed that all domains of the SHPS-J were significantly higher for individuals with insomnia than for good sleepers. CONCLUSIONS: This study confirmed both the reliability and validity of the SHPS-J.

Development of 5-day hikikomori intervention program for family members: A single-arm pilot trial.

BACKGROUNDS: Hikikomori, a severe form of social withdrawal, is increasingly a serious mental health issue worldwide. Hikikomori is comorbid with various psychiatric conditions including depression, social anxiety and suicidal behaviors. Family support is encouraged as a vital first step, however evidence-based programs have yet to be established. Mental Health First Aid (MHFA) is one of the most well-validated educational programs encouraging lay people such as family members, to support close persons suffering from various psychiatric conditions such as depression, anxiety and suicidal behaviors. METHODS: We newly developed an educational program for family members of hikikomori sufferers mainly based on MHFA and 'Community Reinforcement and Family Training (CRAFT)' with role-play and homework. As a single-arm trial, 21 parents (7 fathers and 14 mothers) living with hikikomori sufferers participated in our program with five once-a-week sessions (2 h per session) and six monthly follow-ups, and its effectiveness was evaluated using various self-rated questionnaires. RESULTS: Perceived skills toward a depressed hikikomori case vignette, stigma held by participants, and subscales of two problematic and one adaptive behaviors of hikikomori sufferers were improved throughout the sessions and follow-ups. In addition, positive behavioral changes of hikikomori sufferers such as improved social participation were reported by participants. LIMITATIONS: Single-arm design and evaluation using self-rated questionnaires are the main limitations of the present study. CONCLUSIONS: Our newly developed program has positive effects on family members in their contact and support of hikikomori sufferers. Future trials with control groups are required to validate the effectiveness of this program.

Family Behavioral Repertoires and Family Interaction Influence the Adaptive Behaviors of Individuals With Hikikomori.

Background: Family support is key in the initial stages of psychological support for individuals with hikikomori. However, it remains necessary to confirm the relationship between families' cognitive behavioral factors and the severity of hikikomori to understand ways of improving hikikomori. We examined the influences of family behavioral repertoires for coping with hikikomori and family interaction on the adaptive behaviors of individuals with hikikomori. We employed a control group to examine whether the influence of these adaptive behaviors was unique to families of individuals with hikikomori. Methods: We asked 185 parents of individuals with hikikomori (hikikomori group) and 460 parents of individuals with no experience of hikikomori (control group) to complete the Family Behavioral Repertoire Scale for coping with hikikomori (FBS-H), the Family Interaction Scale for Hikikomori (FIS-H), and the Adaptive Behaviors Scale for Hikikomori (ABS-H). Using the subscales of the ABS-H as the dependent variables, we conducted hierarchical multiple regression analyses wherein family behavioral repertoire was added in Step 1, experience frequency and cognition of contingency were added in Step 2 as control values, family interaction was added in Step 3, and the interaction terms were added in Step 4. Results: The ABS-H total and subscale scores were significantly lower in the hikikomori group than in the control group. The social participation subscale showed the largest difference, while the family subscale showed the smallest. In the hikikomori group, we observed a significant adjusted R 2 for the family and value subscales (Step 1). The ΔR 2 in Step 3 was significant for the interaction and family subscales of the ABS-H. In the control group, significant adjusted R 2 values were found for all ABS-H subscales in Step 1, but the ΔR 2 in Step 3 was not significant for any subscales. Conclusion: Family-related cognitive behavioral factors, such as family behavioral repertoire and family interaction, appear to relate to improvement in hikikomori. Of course, these findings warrant further investigation because we did not examine the longitudinal, causal relations between these variables. In the future, we might also test the effect of family support interventions that target families' behavioral repertoire and family interaction.

Investigation into the plasma concentration of ω3 polyunsaturated fatty acids in Japanese attention-deficit hyperactivity disorder patients.

Several studies report that patients with attention-deficit hyperactivity disorder (ADHD) have a low plasma concentration of polyunsaturated fatty acids (PUFAs). Since fish intake varies among countries and is high in Japan, those results may not apply to Japanese patients with ADHD. However, there is currently not enough evidence to support this. We compared the plasma PUFAs levels of patients with ADHD with the standard reference levels for healthy subjects, and examined the relationship between those PUFAs levels and the subject's psychological evaluation. The subjects were 24 patients (age < 20 years) previously diagnosed with ADHD (according to the DSM-IV-TR criteria) at the psychiatric department of the Nagasaki University Hospital, between November 2010 and November 2015. The plasma concentrations of docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and arachidonic acid (AA) were measured using gas chromatography. Data pertaining to global assessment of functioning (GAF), clinical global impressions, ADHD Rating Scale-IV, and the drug used for treatment (atomoxetine or methylphenidate) were obtained from the medical records. The plasma concentrations of DHA, EPA, and EPA/AA were significantly lower than the normal reference range, indicating that ADHD patients present an imbalance in PUFAs levels. This trend is similar to ADHD patients in other countries and replacement therapy in Japanese ADHD patients may be useful.

[The effect of hikikomori on quality of life].

The purpose of the present study was to examine the effect of hikikomori, a Japanese term denoting "prolonged social withdrawal", on quality of life (QOL). Individuals with hikikomori at present (n = 26) and in the past (n = 31), as well as mildly depressed individuals without hikikomori (n = 114) and highly depressed individuals without hikikomori (n = 27) were requested to complete the WHO Quality of Life 26 (QOL26). The results of MANOVA indicated that the present hikikomori group's scores on the social relationships domains of the QOL26 were significantly lower than the scores of the highly depressed group. The results of this study suggest that it might be important to intervene to improve QOL in individuals with hikikomori.

[Epidemiology of schizophrenia].

Schizophrenia exhibits wide variation in epidemiological characteristics. Through the past few decades, we have learned much about schizophrenia epidemiology, providing important findings for etiological research, clinical care and public health. In this article, we provide overview of current research on incidence, prevalence, risk factors, mortality and outcome of schizophrenia. Contrary to traditional understanding, the incidence and prevalence of schizophrenia show prominent variation between locations. Risk factors for schizophrenia include urbanicity, migration, sex, season of birth and pregnancy and birth complications. Schizophrenia patients have an increased mortality risk compared with the general population. Recent studies about outcome show not so tragic, especially in regard to social functioning. Over the recent decades, circumstances have been changing around schizophrenia. As to treatment, for example, 'the second generation antipsychotics' have replaced conventional ones and 'early intervention' is developing. However, we have only limited evidences of current schizophrenia. Further epidemiological development is needed.