The Strengths and Difficulties Questionnaire (SDQ) - Self-Report. An analysis of its structure in a multiethnic urban adolescent sample

Background: The SDQ is currently one of the internationally most frequently used screening instruments for child and adolescent mental health purposes. However, its structure, cross-cultural equivalence, and its applicability in ethnic minority groups is still a matter of discussion. Methods: SDQ self-report data of 5,379 ethnic Norwegian and 865 ethnic minority adolescents with a variety of national origins was analysed by means of confirmatory factor analysis (CFA). Multi-group comparisons considering equal thresholds combined with more in-depth analyses on factor loadings, residuals, composite reliability, and average amount of variance explained by indicators of respective constructs were performed. Results: CFA suggested a good fit of the five-factor model of the SDQ self-report in the subsample of ethnic Norwegian adolescents and an acceptable fit in ethnic minority subsamples without substantial differences between ethnic Norwegian SDQ data and data of Pakistani or those of 'other ethnic minority' adolescents. When assuming equal thresholds between response categories of the items as well as equal factor loadings the structure in the data significantly differed between ethnic Norwegian and both ethnic minority samples. Some factor loadings and some correlations between constructs significantly differed between ethnic Norwegian and both ethnic minority samples. The correlation coefficients between the hyperactivity factor and the conduct problems factor were too high in all three subsamples in order to establish distinct constructs. Composite reliability and average explained variance of the emotional symptoms factor were good in all samples, whereas they were low for some of the other factors. Conclusions: To some extent the theoretically proposed five-factor structure of the Norwegian version of the SDQ self-report was supported in 15- to 16-year-old adolescents. However, the results of more detailed analyses raise questions about the interpretation of some subscales. When applying this screening method to Norwegian adolescents, our results suggest that the use of the total difficulty score of the SDQ in screening youth should be preferred over the subscale scores.