Abstract
Functional and excessive use of internet are hard to distinguish from each other, and internet use can affect adolescents' development of self-identity. The aim of our study was to investigate the associated relationships between the risk and protective factors for internet use, including parental monitoring, the absorptive dissociative trait, having been bullied, exercise, self-perceived depressive mood, and happiness of 12-year-old adolescents. The Taiwan Birth Cohort Study dataset, which used a national household probability sampling method and included 17,694 12-year-old adolescents, was used for this study. Our results showed that 5.3% of adolescents reported spending more than five hours online during school days. Additionally, adolescents that spent more than five hours online during school days tended to have a higher absorptive trait, perceived less care from mothers, were more likely to have been bullied, and expressed a higher level of depressed mood, which led to a lower level of perceived happiness. Adolescents that spent more than five hours online during school days, compared to those that spent less than an hour online, were more likely to have been bullied, which effected their level of happiness, showing that they may be a group of higher concern. Therefore, spending more than five hours per day online maybe a clinical prevention indicator for problematic internet use.