In chapter one, clinical and anecdotal evidence suggesting that increasing numbers appear to be addicted to using the Internet was outlined. Theoretical and methodological approaches taken towards studying this phenomenon were then detailed and evaluated. It was shown that Pathological Internet Use (PIU) appears to be most prevalent amongst male students and housewives and focused on that involving real time computer mediated communication (CMC) such as Chat rooms and Multi-User Domains (MUDS). In chapter two, two types of synchronous CMC: Chat and interactive games, were described. The immersive nature of the Internet was then explored with reference to those applications. It was then shown that there are particular reasons, such as identity experimentation, why synchronous CMC may be so rewarding as to contribute to the development of Pathological Internet use (PIU). The costs and benefits of synchronous CMC for PI users were then evaluated and the association between PI use and loneliness highlighted. Chapter three presented a study regarding Internet use among 61 computer science students, (a population considered to be high risk for PIU). The survey sought to generate preliminary descriptive data about Internet use in an Irish non-self selected real life environment of Trinity College. A survey was carried out to assess incidence of PIU and patterns of Internet use amongst computer science students and to examine whether PI users would score significantly higher on the UCLA Loneliness scale than Non-PI users. Findings included that among 65 (100%) respondents surveyed, 4 (6.2%) of respondents fitted Young's DSM IV based criteria for Pathological Internet use; PI users spend more time on line a week than non - PI users, (13 to 15 hours against 10 to 12 hours.), and did not as predicted score significantly higher on the UCLA Loneliness Scale than Non-PI users.