Further Validation Of The Internet Addiction Test: Psychometric Characteristics In A Portuguese University Sample

Introduction The Internet Addiction Test (IAT) is a 20-item, self-reported questionnaire that measures the presence and severity of Internet addiction which is an increasing problem in adolescents. Although a Portuguese version IAT has been validated in adults, its psychometric properties have never been evaluated before, in adolescents. Objectives To analyse the reliability and construct and concurrent validity of the IAT in a Portuguese adolescent sample. Methods 772 adolescents (53.5% girls), mean aged 13.21±2.246, answered the Portuguese versions of the IAT and the Portuguese versions of validated scales to evaluate: Cyberbullying, Game Addiction, Agressivity and Anxiety, Depression Scales. To study the temporal stability, 377 (60.5% girls) respondents answered the questionnaires again after approximately four-six weeks. The total sample was aleatory splitted to realize the exploratory and the confirmatory factor analyses. Results Exploratory and confirmatory factor analyses supported a second order two-factor structure - “Isolation and Social Commitment” and F2-“Negligence and Functional Commitment”. The χ2/df value was 2.260 and had a significant p value; it had the lowest RMSEA score = .074 (p< .001) and it had the highest TLI (.980) and CFI (.905). IAT mean scores were no different between genders [Girls=29.25±18.775 vs. Boys: 30.85±17.929, p=.405]. The Cronbach’s alphas were > .85. Pearson correlation between the test and the re-test was r=.660. The IAT, video game addiction (r=.434), Cyberbullying (r=.383), anxiety (r=.209) and depression (r=.263) were significantly correlated (p<.001). Conclusions The Portuguese IAT has good reliability and validity, showing to be an adequate instrument for measuring Internet Addiction symptoms in Portuguese Adolescents.