The Strengths and Difficulties Self-Report Questionnaire as a screening instrument in Norwegian community samples.

This study reports on the application of the Norwegian self-report version of the Strengths and Difficulties Questionnaire (SDQ-S). The application of the SDQ-S was not motivated by a wish to reveal the prevalence of psychiatric disorders, but rather to set the stage for routine screening as part of schools' efforts to inform themselves about the life of adolescents at school. The survey included 4167 young people aged 11 to 16 years, attending 66 primary and secondary schools in Northern Norway. The respondents comprised 80.2% of the total population in these grades in the target area. Structural analysis of the instrument, including confirmatory factor analysis, internal consistency and intra- and cross-scale correlations revealed somewhat variable psychometric properties. Model modification suggested several ways of improving the structural psychometric properties of the SDQ-S. Norwegian cut-off points were similar to those found in other Scandinavian studies. About one third of the subjects reported at least minor perceived difficulties, while about 5% reported definite or severe difficulties. These difficulties were strongly associated with all symptom scales. Girls reported a significantly higher level of emotional problems and better prosocial functioning. Boys reported significantly higher scores on the externalising scales and on peer problems. The SDQ-S may be judged as an efficient and economical screening instrument for preventive research on large community samples. However, efforts should be made to improve its psychometric structure.