Do the Smartphone Addiction Scale-Short Version (SAS-SV) and the Internet Addiction Test (IAT) assess two distinct internet-related disorders? A comparative analysis using CFA, Set-ESEM, and Full-ESEM models

This study investigated whether the Internet Addiction Test (IAT) and the Smartphone Addiction Scale-Short Version (SAS-SV) capture separate Internet-related disorders, comparing CFA, Set-ESEM, and Full-ESEM models on a sample of 839 participants (59.1% females; <i>M</i>_age = 30.31, <i>SD</i> = 10.05). The ESEM solution was selected based on fit-indices [<i>χ</i>² = 506.810; <i>df </i>= 248, <i>p </i>&lt; .001; CFI = .976; TLI = .963; RMSEA = .035 (.031–.040); SRMR = .019; AIC = 70,390.955; BIC = 71,269.364; aBIC = 70,678.693], inter-factor correlations (.232 &lt; <i>r &lt;</i> .595), parameter estimates (significant primary target loadings and reduced cross-loadings), and theoretical interpretability. This study highlights the conceptual overlap between Internet and smartphone addiction and emphasises the importance of comparing CFA, Set-ESEM, and Full-ESEM models when two or more sets of constructs are included in a single model.