The interest on the possible problems that might be associated with heavy use of the web has increased. The aim of this study was to test the correlates and validity of the Finnish version of the Internet Addiction Test.

1825 students filled a web-based questionnaire that included questions on socio-demographic background factors, reasons for use of the internet, symptom score measures and questions of use of substances. The back-translation of the Internet Addiction Test (IAT) was reviewed by the developer of the scale.

Almost all (99.6%) respondents used the web more than once a week. Those with a CAGE score 2 or above had a mean of 39.4 on the IAT and those below 2 had a mean of 35 on the IAT (p<0.001). Those who were more distressed had a higher mean score on the IAT than those who did not reach the cut-point for being distressed (43.8 vs. 35.2, respectively, p<0.001). High IAT score was also significantly associated with use of the internet for chatting and sexual purposes (p<0.001). Using factor analysis, we found a two factor solution: 1) a depressive isolation factor (eigenvalue 15.02) and 2) loss of control factor (eigenvalue 1.53). The Cronbach-α for the sum factors were 0.91 and 0.81 respectively.

The IAT seems to provide a valid measurement of harmful use of the internet as the score was significantly associated with variables tapping psychopathology. Most of the variance in the score of IAT is explained by depressive isolation.