Psychometric properties of the Turkish version of the Internet Addiction Test (IAT) Murat Boysan a, ⁎, Daria J. Kuss b , Yaşar Barut c , Nafi Ayköse d , Mustafa Güleç e , Osman Özdemir f a Yüzüncü Yıl University, Faculty of Arts, Department of Psychology, Van, Turkey b Nottingham Trent University, Department of Psychology, Nottingham, England c Ondokuz Mayıs University, Department of Psychological Counseling, Samsun, Turkey d Ankara University, Department of Psychological Counseling, Ankara, Turkey e İzmir Kâtip Çelebi University, Faculty of Medicine, Department of Psychiatry, İzmir, Turkey f Yüzüncü Yıl University, Faculty of Medicine, Department of Psychiatry, Van, Turkey HIGHLIGHTS • The Turkish version of the Internet Addiction Test (IAT) has sound psychometric properties. • Of the studies to date, the IAT revealed the highest internal and temporal reliability. • Internet addiction is correlated with pathological dissociation and obsessionality. • Internet addicts are more likely to cope emotionally with stressful situations. abstract article info Article history: Received 21 February 2015 Received in revised form 18 August 2015 Accepted 3 September 2015 Available online 8 September 2015 Keywords: Dissociation Obsessive–compulsive disorder Internet addiction Coping Reliability Validity Objective: Of many instruments developed to assess Internet addiction, the Internet Addiction Test (IAT), an ex- panded version of the Internet Addiction Diagnostic Questionnaire (IADQ), has been the most widely used scale in English and non-English speaking populations. In this study, our aim was to investigate the psychometric properties of short and expanded versions of the IAT in a Turkish undergraduate sample. Method: Overall, 455 undergraduate students from Turkey aged between 18 and 30 participated in the study (63.53% were females). Explanatory and confirmatory factor analytic procedures investigated factor structures of the IADQ and IAT. The Internet Addiction Scale (IAS), Coping Inventory for Stressful Situations (CISS), Obsessive Compulsive Inventory—Revised (OCI-R) and Dissociative Experiences Scale (DES) were administered to assess convergent and divergent validities of the IADQ and IAT. Internal consistency and 15-day test–retest reliability were computed. Results: In the factorial analytic investigation, we found a unidimensional factor structure for each measure fit the current data best. Significant but weak to moderate correlations of the IADQ and the IAT with the CISS, OCI-R and DES provided empirical evidence for divergent validity, whereas strong associations with the subscales of the IAS pointed to the convergent validity of Young's Internet addiction construct. Internal consistency of the IADQ was weak (α = 0.67) and of the IAT was high (α = 0.93). Temporal reliability of both instruments was very high (α = 0.81 and α = 0.87; respectively). Conclusion: The IAT revealed promising and sound psychometric properties in a Turkish sample. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction Internet addiction is characterized by excessive and uncontrollable Internet use, and has been identified as a severe problem among young populations (Young, 1998a). Internet addiction prevalence estimates vary across countries due to differences in diagnostic criteria as well as the psychometric tools utilized in assessment (Kuss, van Rooij, Shorter, Griffiths, & van de Mheen, 2013). A recent systematic lit- erature review has indicated currently 21 different instruments that exist to measure Internet addiction (Kuss, Griffiths, Karila, & Billieux, 2014). Young's Internet addiction construct appears as one of the earliest conceptualizations and is still adopted nowadays. The ambiguity in a clinical diagnosis of Internet addiction has led to a lack of consensus on a gold standard, making Young's tools more popular as well-known and Addictive Behaviors 64 (2017) 247–252 ⁎ Corresponding author at: Yüzüncü Yıl University, Faculty of Arts, Department of Psychology, P.O. Box. 65080 Campus, Van, Turkey. E-mail addresses: boysan.murat@gmail.com (M. Boysan), daria.kuss@ntu.ac.uk (D.J. Kuss), yasarbarut@yahoo.com (Y. Barut), nafiaykose@hotmail.com (N. Ayköse), mustafagulec78@yahoo.com (M. Güleç), drosmanozdemir@yahoo.com (O. Özdemir). http://dx.doi.org/10.1016/j.addbeh.2015.09.002 0306-4603/© 2015 Elsevier Ltd. All rights reserved. Contents lists available at ScienceDirect Addictive Behaviors journal homepage: www.elsevier.com/locate/addictbeh