Relationship between internet addiction and depression among Japanese university students

Background: Internet addiction (IA) has various adverse effects. We sought to elucidate the relationship between IA and depression among university students and to identify factors associated with IA. Methods: Anonymous, self-administered questionnaires were distributed to 5,261 students and comprised basic characteristics, lifestyle habits, anxieties, the Internet Addiction Test (IAT), and the Center for Epidemiological Self-Depression Scale. Results: Responses were obtained from 4,490 students (response rate: 85.3%). After excluding those with missing responses, 3,251 participants were analyzed (valid response rate: 61.8%). Logistic regression analysis with severity of IA as the independent variable and depression as the dependent variable revealed that the odds ratio (OR) for depression increased with severity of IA (mild addiction: OR = 2.87, 95% confidence interval [CI] = 2.45 - 3.36; severe addiction: OR = 7.31, 95% CI = 4.61 - 11.61). In a logistic regression analysis with mobile phone use as the independent variable and IA as the dependent variable, the highest OR was for message board use (OR = 3.74, 95% CI = 2.53 - 5.53) and the lowest OR was for use of LINE instant messenger (OR = 0.59, 95% CI = 0.49 - 0.70). Logistic regression analysis with academic department as the independent variable and internet addiction as the dependent variable revealed high ORs for the humanities department (OR =1.59, 95% CI =1.18 - 2.16) and fine arts department (OR =1.55, 95% CI =1.07 - 2.23). Limitations: The main limitations were the cross-sectional design, low valid response rate, single-university setting, and possible social desirability bias. Conclusions: Our results suggest a relationship between IA and depression in university students. IA tendency differed according to mobile phone use and academic department, suggesting these factors are associated with IA.