Tehran University of Medical Sciences Iranian Journal of Psychiatry 1735-4587 13 2 2018 04 23 103 110 EN Malihe Farahani West Tehran Branch-Azad University, Department of Psychology Seyyed Salman Alavi Psychiatry and Psychology Research Center, Tehran University of Medical Sciences, Tehran, Iran. Mahmood Mirzamani Bafghi Department of Psychology, College of Education and Psychology, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran. Soudeh Esmaeeli Alamooti Department of Psychology, Allame Tabatabaee University, Tehran, Iran. Mohammadreza Mohammadi Psychiatry and Psychology Research Center, Tehran University of Medical Sciences, Tehran, Iran 2017 09 11 Objective: Problematic internet use is an important social problem among adolescents and has become a global health issue. This study identified predictors and patterns of problematic internet use among adult students. Method: In this study, 400 students were recruited using stratified sampling technique. Participants were selected among students from 4 universities in Tehran and Karaj, Iran, during 2016 and 2017. Internet Addiction Test (IAT), Millon Clinical Multiaxial Inventory - Third Edition (MCMI-III), Structured Clinical Interview for DSM (SCID-I), and semi-structured interview were used to diagnose internet addiction. Then, the association between main psychiatric disorders and internet addiction was surveyed. Data were analyzed using SPSS18 software by performing descriptive statistics and multiple logistic regression analysis methods. P- Values less than 0.05 were considered statistically significant. Results: After controlling the demographic variables, it was found that narcissistic personality disorder, obsessive- compulsive personality disorder, anxiety, bipolar disorders, depression, and phobia could increase the odds ratio (OR) of internet addiction by 2.1, 1.1, 2.6, 1.1, 2.2 and 2.5-folds, respectively (p-value<0.05), however, other psychiatric or personality disorders did not have a significant effect on the equation. Conclusion: The findings of this study revealed that some mental disorders affect internet addiction. Considering the sensitivity and importance of the cyberspace, it is necessary to evaluate mental disorders that correlate with internet addiction. https://ijps.tums.ac.ir/index.php/ijps/article/view/1196 https://ijps.tums.ac.ir/index.php/ijps/article/download/1196/725