Relationship between Internet Addiction and Poor Mental Health among Japanese Adolescents

Internet addiction and poor mental health are two pervasive problems during adolescence. This study aimed to determine whether Internet addiction and poor mental health status exhibited a bidirectional relationship in which either variable could become a risk factor for the onset of the other.

Longitudinal school-based survey with a baseline sample of 1547 students among 8 schools (10th graders) in Japan surveyed in 2015 and followed up 1 year later. The schools are located in the middle city. We assessed internet addiction using the Japanese version of the Diagnostic Questionnaire developed by Young and mental health status using the 12-item General Health Questionnaire. Regression analyses including the covariates tested whether Internet addiction was related to the onset of poor mental health among youth who had never internet addiction, and poor mental health was related to the onset of internet addiction.

The incidence for Internet addiction and poor mental health during one year were 22.0% and 8.8%, respectively. Multiple regression analyses showed that poor mental health (adjusted odds ratio: 2.17 [95%CI: 1.45–3.25]) promoted new onset of Internet addiction and Internet addiction (adjusted odds ratio: 2.39 [95%CI: 1.36–4.20]) also promoted new onset of poor mental health.

Internet addiction and poor mental health status each increased the risk of onset of the other. Adolescents, their parents and schools need to take policies to use properly Internet.