Table 1.

Assessment instruments for internet addiction.

Study	Instrument	Diagnostic criteria	Structure
Young, 1998	Addiction Diagnostic Questionnaire	Pathological gambling criteria	8 items; measure scored dichotomously
Young, 1998	Internet Addiction Test	Dependency criteria	20 items 1- to 5- Likert-scale
Chen et al., 2003	Chen Internet Addiction Scale	Internet addiction	26 items 4-point Likert-scale
Caplan, 2002	Generalized Problematic Internet Use Scale (GPIUS)	Based on Davis’ (2001) cognitive-behavioral model of problematic Internet use	29 items self-report questionnaire rated on 5-point Likert-scale
Demetrovics et al., 2008	Problematic Internet Use Questionnaire (PIUQ)	Focused on obsession, neglect, and control disorder	30 items scored on a 5-point Likert-scale