Prof. Zsolt Demetrovics is Dean of the Faculty of Education and Psychology, Director of the Institute of Psychology and Head of the Department of Clinical Psychology & Addiction at the Eötwös Loránd University in Budapest, Hungary; As a clinical psychologist specialised in addiction, Demetrovicz is involved in numerous research projects looking at problematic internet use, and consequently participates in the work of the new European Problematic Use of the Internet Network (EU PUI). Many different forms of problematic online behaviour are included within the PUI term: gaming; video streaming; viewing pornography; shopping; social media use.