Aim: Internet addiction disrupts the daily lives of adolescents. We investigated the prevalence of Internet addiction in junior high school students, elucidated the relation between Internet addiction and mental states, and determined the factors associated with Internet addiction in adolescents.Methods: Junior high school students (aged 12-15 years) were assessed using Young's Internet Addiction Test (IAT), the Japanese version of the General Health Questionnaire (GHQ), and a questionnaire on access to electronic devices.Results: Based on total IAT scores, 2.0% (male, 2.1%; female, 1.9%) and 21.7% (male, 19.8%; female, 23.6%) of the total 853 participants (response rate, 97.6%) were classified as addicted and possibly addicted, respectively. Total GHQ scores were significantly higher in the addicted (12.9 AE 7.4) and possibly addicted groups (8.8 AE 6.0) than in the non-addicted group (4.3 AE 4.6; P < 0.001, both groups). A comparison of the percentage of students in the pathological range of GHQ scores revealed significantly higher scores in the possibly addicted group than in the non-addicted group. Further, accessibility to smartphones was significantly associated with Internet addiction.Conclusion: Students in the addicted and possibly addicted groups were considered 'problematic' Internet users. Use of smartphones warrants special attention, being among the top factors contributing to Internet addiction.

Background: Few studies have explored school refusal in children with autism spectrum disorder (ASD), despite being considered a serious problem. One of the leading causes of school refusal is bullying, which is defined by the feelings of students who are bullied or not, and psychological suffering caused by a psychological or physical attack. This study investigated the characteristics of school refusal in children with ASD. Methods: A total of 94 outpatients with school refusal and ASD and 143 outpatients with school refusal without ASD aged 6-18 years were included. Chi squared tests and Mann-Whitney tests were used to compare the characteristics of school refusal in children with and without ASD. Univariate and multivariate logistic regression analyses were performed to analyze the reasons for school refusal in children with ASD by sex. Results: School refusal significantly occurred earlier in children with ASD than in those without. In addition, "bullying" was significantly associated with school refusal in both boys and girls with ASD. Conclusions: These findings suggest that school refusal should be monitored early in children with ASD. The importance of recognizing bullying among children with ASD should be highlighted as an opportunity for early intervention.

The DQ scores obtained using the KSPD were a reasonable estimate of cognitive ability in children with ASD. The KSPD may be a useful alternative to the WISC-III for young children with ASD and could facilitate earlier assessment.