Internet and mobile phone text-messaging dependency: Factor structure and correlation with dysphoric mood among Japanese adults

Unhealthy use of the Internet and mobile phones is a health issue in Japan. We solicited participation in this questionnaire-based study from the employees of a city office in Kumamoto. A total of 92 men and 54 women filled in the Internet Addiction Questionnaire (IAQ), the Self-perception of Text-message Dependency Scale (STDS), and the Hospital Anxiety and Depression Scale (HADS). The prevalence of ''light Internet addiction'' and ''severe Internet addiction'' were 33.7% and 6.1% for men whereas they were 24.6% and 1.8% for women. The prevalence of ''light mobile phone text-message addiction'' was 3.1% for men and 5.4% for women. There were no cases of ''sever text-message addiction''. We found a two-factor structure for the IAQ and a three-factor structure for the STDS. We also performed an EFA of the IAQ and STDS subscales, and this revealed a two-factor structure - Internet Dependency and Text-message Dependency. An STDS subscale, Relationship Maintenance, showed a moderate factor loading of the factor that reflected unhealthy Internet use. In a path analysis, Depression was associated with both Internet Dependency and Text-message Dependency whereas Anxiety was associated negatively with Text-message Dependency. These results suggest applicability of the IAQ and STDS and that Internet and Text-message Dependences are factorially distinct.