Researchers have developed a new method designed to help detect hikikomori at an earlier stage and provide treatment


Kyushu University researchers have developed a new ‘Hikikomori Questionnaire’ in an effort to detect the condition at an earlier stage.

Preliminary results show that isolation is a possible factor that can distinguish between non-hikikomori and pre-hikikomori individuals, providing possible validation of the new questionnaire as a tool for early detection and treatment.

Hikikomori is a complex pathological condition where an individual withdraws from society and remains at home almost every day for more than six months. Although it may be viewed as a condition unique to Japan, hikikomori has been reported globally from across Asia, to Europe and North America.

“Hikikomori was first defined in 1998. As we studied the condition, we found that it is a very complex pathology caused by an overlap of physical, societal, and psychological conditions,” explains Takahiro A. Kato of Kyushu University’s Faculty of Medical Sciences and first author of the study.

“Its growing international recognition has put hikikomori into the purview of many researchers and medical professionals, especially on the heels of the years long COVID-19 pandemic. Just this year, Hikikomori was recognized in the revised edition of the DSM-5.”

Kato and his team have been working on measures to evaluate, identify, and treat hikikomori patients, to the point of opening the world’s first outpatient clinic for hikikomori individuals in 2013. In 2018, the team developed the ‘Hikikomori Questionnaire,’ or HQ-25, that was design to assess whether individuals under social withdrawal after six months are symptomatic of hikikomori.

“This questionnaire allowed us to identify symptomatic individuals with hikikomori. As our work progressed, we found that we needed an assessment tool that could evaluate symptomatic individuals at an earlier stage to help detect and potentially prevent hikikomori,” continues Kato.

The new Hikikomori Questionnaire, or HQ-25M—made in collaboration with Nihon University and Oregon Health and Science University—is composed of 25 questions that evaluate the three subfactors of socialization, isolation, and emotional support on a scale to 0–4, 4 being ‘strongly agree.’

For example, questions such as ‘I feel uncomfortable around other people’ gauge socialization, while ‘there are few people I can discuss important issues with’ covers emotional support.

The pilot test of the new questionnaire, reported in Psychiatry and Clinical Neurosciences, was conducted with 762 Japanese individuals. The questionnaire first asked about the individual’s social withdrawal status in the prior month in order to categorize participants into hikikomori, non-hikikomori, and pre-hikikomori groups. The team also added a questionnaire that evaluates the individual’s psychological distress during the same month.

“We analyzed the data to see any comparable differences between the different category groups,” explains Kato. “Multiple models showed us that hikikomori groups scored significantly higher on all metrics compared to non- and pre-hikikomori.”

Interestingly, between the pre- and non-hikikomori respondents, of all the three subfactors that were measured, the isolation subfactor was the only one that showed a significant difference in scores.

While still preliminary, the team is pleased with their initial findings and plans to use them to improve their questionnaire and data collecting.

“These initial findings are promising and show that our questionnaire may be a good tool for early detection of hikikomori,” concludes Kato.

“Nonetheless, we have to work on expanding and diversifying our sample size and fine tune our questions. Moreover, since the hikikomori pathology is being reported around the world, we must work with researchers and patients outside of Japan.”

There are limited studies pertaining to the etiology of hikikomori. Our study aimed to identify factors associated with the occurrence and severity of hikikomori during early adolescence, which is a critical period in the development of the disorder.

First, we developed a novel scale that could measure the severity of hikikomori and accurately identify those suffering from it, by comparing the results with those of control participants. This scale was based upon the findings of other research that identified school absenteeism and being house bound as two critical symptoms. We believe this scale can be useful but will require further validation by other studies, especially to improve upon its specificity as there may be some crossovers with mood disorders and agoraphobia.

Factors Associated with the Occurrence of Hikikomori
Previous research has found that individuals who exhibit hikikomori are more likely to be male [12, 14], however, gender was not significantly related to hikikomori severity in our study.

Our investigation of environmental factors that may be associated with the occurrence of hikikomori found that the prevalence of psychiatric disorders among parents was significantly higher in the hikikomori group. This indicated that there may be some genetic predisposition; perhaps related to stress tolerance, coping ability, or resilience; preventing adolescents with hikikomori from adequately coping with stressors such as interpersonal problems at school or poor academic performance. A recent preliminary study has shown blood biomarkers uric acid and high-density lipoprotein cholesterol as possibly correlated with an underlying biological pathology of hikikomori [57]. Individual psychological factors including interpersonal problems [14], coping difficulties, conflicting demands, reduced autonomy [58], low self-esteem [34], and a predisposed introverted personality [31] have been shown to play some role in hikikomori propensity. However, the extent to which these underlying vulnerabilities depend on a biological foundation requires further research. The novel scale we designed to measure the environmental factors also requires further testing and validation.

We also found that the hikikomori group had significantly lower scores for communication between parents and significantly higher scores for conflict between parent and child. Overuse of the Internet was also significantly higher in the clinical group. These could be important risk factors for hikikomori but could also be a result of the hikikomori itself. When personal stress and a negative family environment are added to a nonspecific vulnerability, signs of hikikomori could emerge along with adaptation issues. Similarly, maladaptation (in the form of hikikomori) may increase conflicts between parent and child and perhaps eventually lead to decreased communication between parents should they become overwhelmed. Familial factors, including an absent father, overdependence between mother and child [3], highly educated parents, and maternal panic disorder [59] have all been associated with hikikomori.

Overuse of the Internet may merely be a product of the limited available things to do when confined to the home, and more investigation is needed to uncover the relationship between Internet use and hikikomori, specifically to ascertain whether Internet use actively worsens symptoms or whether it is purely a recreational activity replacing social interaction.

Our CBCL results showed that middle school hikikomori patients had significantly higher mean scores for all the syndrome subscales and the total score, as compared to the control group. Although the total mean CBCL score for the hikikomori group was in the clinical range, all eight syndrome subscales were subclinical. This may be interpreted as follows: each of these psychiatric signs associated with hikikomori may not be considered clinically serious when considered alone; however, the combination may warrant psychiatric consultation. Given that there is no distinctive psychiatric sign that is specific to “clinical” hikikomori, as compared to other psychiatric conditions, there may be no single strong predictor that could be used for early detection. Rather, its occurrence will need to be judged by analyzing a combination of features that will change along a spectrum that has “severe hikikomori” at its one extreme [15, 16, 38, 39]. Based on our findings, it is unlikely that a specific vulnerability is the foundation of this condition and it is unclear whether the comorbidities reported thus far [10,11,12,13] may be secondary to the development of hikikomori.

Factors Associated with the Severity of Hikikomori
We used multiple regression analyses to investigate environmental factors and psychological characteristics that may be associated with hikikomori severity. The CBCL syndrome subscale “withdrawn” was found to contribute the most to hikikomori. This subscale evaluates the psychological tendencies of hikikomori and is one way to quantify “affinity for hikikomori,” as mentioned in the Cabinet Office reports [15, 16]. However, since we tried to investigate psychological factors that may have played a role in social withdrawal (hikikomori affinity) the “withdrawn” phenotype was too centrally involved to be useful and thus could not function as an independent variable in our model due to multicollinearity issues.

The results from our cross-sectional multiple regression analysis revealed that the following independent variables were correlated with hikikomori severity: “somatic complaints,” “anxious/depressed,” “overuse of the Internet,” and “lack of communication between parents”. It is interesting to note that “lack of communication between parents” was a correlate but “conflict between parents” was not. Could this indicate that regardless of whether parents frequently quarreled, more communication between parents could be a protective factor for adolescents with a tendency toward hikikomori? A more sensitive measure of the quality of the communication, such as the Family Assessment Device [60], would be useful to interrogate this further.

It is also not easy to tell whether anxiety and depression are triggers for hikikomori or simply co-occur. They have been identified as factors in other studies, but the exact relationship remains unclear [11, 12].

The relationship between somatic complaints and hikikomori is also unclear. Somatization could be related to nonspecific genetic vulnerabilities mentioned above (e.g. low stress tolerance). As a result of somatization, those with early hikikomori may frequently visit pediatricians about undefined complaints, which presents an opportunity for early detection. Although early screening for hikikomori may be difficult, the symptom of “school refusal” seems to be highly indicative [34,35,36]. One must also consider others on the hikikomori spectrum, who may have no problems attending school but communicate very little with people other than the members of their own families (the “hikikomori affinity group”).

Therapeutic Interventions
Parents should be encouraged to control Internet use in hikikomori children. These recommendations should be emphasized in support programs for hikikomori that target middle school students. One example is an administrative intervention program in French schools that has reduced the number of adolescent drop outs, by making the school staff focus intensely on any student who is absent for 10 half-days in a month. If absenteeism persists, the case is referred to a public prosecutor, unless the situation is handled medically or socially [61]. Unfortunately, hikikomori sufferers are often concealed by families, stopping judiciary and administrator bodies from intervening, thereby greatly impeding prevention and intervention programs. Such situations could even be viewed as “social neglect.” Social welfare services that encourage parents to address difficulties together with their child, especially through home-visit programs, may be effective for decreasing hikikomori severity and duration [21, 36, 62, 63]. Pre-school developmental-behavioral screening and consecutive support programs may also help prevent early hikikomori [64] but adolescence is a critical period for intervention.

reference link :

Original Research: Open access.
One month version of Hikikomori Questionnaire‐25 ( HQ‐25M ): Development and initial validation” by Takahiro A. Kato et al. Psychiatry and Clinical Neurosciences


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