Text messaging: are dependency and Excessive Use discretely different for Japanese university students?

Text messaging may be excessive and young people may be dependent on it. We distributed the Self-perception of Text-message Dependency Scale (STDS), Hospital Anxiety and Depression Scale (HADS), Temperament and Character Inventory (TCI), and Relationship Questionnaire (RQ) to 223 Japanese university students in a two-wave study, separated by a 5-month interval. The STDS yielded a three-factor structure. The STDS scores across the two measurement occasions were stable across time (except for the Relationship Maintenance subscale). A hierarchical cluster analysis suggested a three-class structure interpreted as Normal Users, Excessive Users, and Dependent Users. Excessive Users and Dependent Users were characterized by a young age at initial mobile phone use, more frequent use of text messaging, higher Novelty Seeking, and better Other-Model patterns of adult attachment. Unlike Excessive Users, Dependent Users were characterized by lower Self-directedness, poorer Self-Model of adult attachment, and higher anxiety and depression. The Excessive Users, but not the Dependent Users, were characterized by high Reward Dependence and Co-operativeness. The present study demonstrated that the STDS has a robust factor structure, good construct validity, and temporal stability (except for Relationship Maintenance subscale); students could be classified into normal, excessive, and Dependent Users of the text messaging; and Dependent Users were characterized by Excessive Use and personality immaturity.