RESUMO
This study was conducted in order to determine the validity and reliability of Chen Internet Addiction Scale [CIAS] among the medical students of Tehran University of Medical Sciences. This was a cross sectional study on 214 medical students of Tehran University who completed the Chen Internet Addiction Scale [CIAS] and Internet Addiction Scale [IAS] in autumn and winter of 2010-2011. The sampling was performed with available sampling method. After translation of CIAS, the face validity was confirmed by three community medicine specialists. Then IAD, demographic and internet use data forms were filled by the medical students. Validity and reliability of CIAS questionnaire was evaluated with factorial analysis, internal consistency, convergent validity, and Cronbach alpha test by SPSS soft ware. In the validity investigation of CIAS, convergent validity shows [r=0.85] with [P=0.001] and factorial analysis by varimax rotation, revealed five factors. In the reliability investigation of CIAS, results of cronbach alpha, was [alpha =0.93]. The validity and reliability of CIAS was acceptable but due to the lack of an approved gold standard in the diagnosis of internet addiction, further studies are needed for agreement on clinical diagnostic criteria in order to determine proper cut off point for the questionnaire. This is a fundamental step in the planning, preventing and treatment of this disorder