Prevalence of Internet addiction in Japan: Comparison of two cross-sectional surveys.

BACKGROUND

Internet addiction is a serious problem, and the incidence has increased significantly in recent years. In two cross-sectional studies over a 4-year period, we investigated Internet addiction in adolescents and evaluated the resulting changes in their lives.

METHODS

Junior high-school students (aged 12 to 15 years) were assessed in 2014 (survey I) and in 2018 (survey II). They filled out Young's Internet Addiction Test (IAT), the Japanese version of the General Health Questionnaire, and a questionnaire on sleep habits and usage of electric devices.

RESULTS

In total, 1,382 students were recruited for the two surveys. The mean IAT score was significantly higher in survey II (36.0 ± 15.2) than in survey I (32.4 ± 13.6) (P < 0.001). The increase in total IAT score indicates that the rate of Internet addiction was significantly higher in 2018 than in 2014. For each subscale of the General Health Questionnaire, social dysfunction scores were significantly lower in survey II than in survey I (P = 0.022). During the weekend, mean total sleep time was 504.8 ± 110.1 min, and the time awake was 08:02 h in survey II; the total sleep time and time awake were significantly longer and later, respectively, in survey II than in survey I (P < 0.001, P = 0.004, respectively). Smartphone use was also significantly higher in survey II than in survey I (P < 0.001).

CONCLUSIONS

The prevalence of Internet addiction differed over the 4 years of this study.