Background: To investigate the phenomenon of internet addiction and concurrent social (off-line) behaviours of an adolescent population a cross-sectional survey of the entire adolescent student population (N = 1270, aged 14–18) of the island of Kos in Greece was conducted.
Method: Completion by the survey participants of a demographic questionnaire, the 8-question YDQ (Diagnostic Questionnaire for Internet Addiction) and the 20-question IAT (Internet Addiction Test), followed by comparative analysis between and within usage groups.
Results: Results demonstrate that 7.2% of male and 5.1% of female internet users present addictive behaviours while using the internet.
Conclusions: Anti-social, aggressive behaviours were significantly correlated with an increase to the pattern of abusive internet use in both sexes. Boys and girls had distinct profiles of off-line and online preferences. Boys tended to favour interest-driven online activities as their levels of addictive behaviour increased while girls favoured communication-driven online activities.