Previously, we conducted a statistical case-control study of adolescent Hikikomori patients in Japan using the Parental Assessment of Psychological, Behavioral and Environment Scales. That study did not reveal any pathologies specific to Hikikomori patients. On the other hand, environmental factors such as “lack of communication between parents” and “overuse of the Internet” were shown to be significant predictors of Hikikomori severity.

In this study, using the same methodology as our previous study in Japan, we conducted a case-control study in France. The following questions were examined : (1) whether the pathology of Hikikomori patients in Japan and France is the same, and (2) whether the environmental factors associated with the severity of Hikikomori are the same in Japan and France.

Using CBCL and our original scales, we descriptive-statistically compared clinical and subclinical psycho-behavioral characteristics of adolescent Hikikomori patients and a control group. In addition, environmental factors that make Hikikomori more severe were clarified by multiple regression analysis.

The results showed that there was no difference in the pathology of Hikikomori between Japan and France. On the other hand, the statistical predictors of Hikikomori severity were “lack of communication between parents and children” and “Lack of communication with the community,” which differed from those in Japan.

Although it is safe to assume that Japanese and French Hikikomori’s pathology is generally the same, different strategies may be needed to prevent the onset of Hikikomori and to stop it from becoming severe.

No significant relationships.

COVID-19-related physical isolation, fear and anxiety determined de novo mental illnesses, by potentially facilitating the emergence of Hikikomori traits (i.e., a severe social withdrawal condition).

The present study aims at screening a cohort of university students for the Hikikomori traits and assessing a set of psychopathological determinants associated with Hikikomori, particularly boredom and loneliness dimensions.

A cross-sectional web-based survey was carried out by administering Hikikomori Questionnaire (HQ-11), Italian Loneliness Scale (ILS), Multidimensional State Boredom Scale (MSBS), Depression Anxiety Stress Scale (DASS-21) and Toronto Alexithymia Scale (TAS-20).

1,148 respondents (767 women and 374 men, mean age: 23.2±SD=2.8 years old) were recruited. 70.7% declared to have experienced psychological distress. HQ-11 average total score was 18.4±SD=7.5 with statistically significant higher values in the males (p=0.017) and amongst students studying Informatics, Mathematics/Physics/Chemistry, Science of Communication and Engineering. The HQ-11 positively correlated with ILS (r=0.609), MSBS (r=0.415), TAS-20 (r=0.482) and DASS-21 (r=0.434).

This study represents the first screening of the Hikikomori phenomenon in Italian university students. Hikikomori traits appear to be particularly represented in the Italian youth population and should be carefully investigated in future studies.

No significant relationships.

Social withdrawal, or hikikomori, is one of Japan’s most serious psychosocial issues. The concept gained international attention around 2010 and widespread psychiatric epidemiological studies have since been conducted.

With an understanding of the extensive range of hikikomori circumstances as a spectrum, we aimed to quantitatively measure the severity of hikikomori in adolescent subjects, an age group considered particularly susceptible to the condition, and to identify factors associated with its severity.

We selected population demographics, socioeconomic data, and psycho-behavioral characteristics as factors related to hikikomori and explored their associations with hikikomori severity using cross-sectional analysis. Subjects were a patient group of middle school students examined as outpatients at a psychiatric clinic during adolescence for a chief complaint of hikikomori and a control group of middle school students matched for sex and age. Subjects’ parents completed a questionnaire pertaining to their child’s hikikomori symptoms and living environment along with the Child Behavior Checklist (CBCL). The data collected was then statistically analyzed.

T-test results demonstrated that scores for all CBCL syndrome scales were significantly higher in the patient group, but no scores fell within the clinical range. Multiple regression analysis revealed that being anxious/depressed, somatic complaints, lack of communication between parents, and overuse of the Internet were statistical predictors of hikikomori severity.

It may be possible to prevent hikikomori from becoming severe if the above predictors are used to identify high-risk individuals requiring active intervention while hikikomori is at an early stage.

No significant relationships.

No significant relationships.

Self-harm and suicidal behaviour are recognised as public health concerns. Prolonged social withdrawal behaviour, or hikikomori, is reported as a risk factor for suicidal behaviour.

To examine the occurrence and additional risk of prolonged social withdrawal behaviour on self-harm and suicidal behaviour among Chinese university students.

A cross-sectional online survey was conducted with three universities in southern China. A two-stage random sampling was adopted for recruitment, with students in different years of study, in different departments of each participating university. Hierarchical logistic regression analyses were conducted to investigate the sociodemographic and psychological correlates of self-harm and suicidal behaviours among male and female participants with hikikomori status.

Of the students who completed the online survey, 1735 (72.23%) were included in the analysis; 11.5% (n = 200) reported self-harm behaviour and 11.8% (n = 204) reported suicidal behaviours in the past 12 months. Men showed a higher prevalence rate of self-harm than women (14.7% v. 10.8%, P = 0.048), but a similar rate of suicidal behaviours (11.9% v. 11.3%, P = 0.78). The overall prevalence rate of social withdrawal behaviour was 3.2% (7.0% for men and 2.3% for women, P < 0.001). Prolonged social withdrawal behaviour status was significantly associated with self-harm (odds ratio 2.00, 95% CI 1.22–3.29) and suicidal behaviour (odds ratio 2.35, 95% CI 1.45–3.81). However, the associations became statistically insignificant after adjustment for psychological factors in the final models in the logistic regression analyses.

Prolonged social withdrawal behaviour appears to be associated with self-harm and suicidal behaviour, but psychological factors have stronger links with suicidality.