Background: The strengths and difficulties questionnaire (SDQ) is now one of the most commonly used instruments for screening child psychiatric morbidities. Psychometric studies in the West affirm its reliability and validity, but similar studies are scarce among non-Western populations. This is an important gap because cultural differences can influence how children's behaviours are perceived and rated. This study explores the psychometric properties of the Chinese version of the SDQ among children in Hong Kong.
Method: The SDQ was translated into Chinese. A community sample of 3,722 students between 6 and 12 years were recruited by stratified random sampling from across the whole of Hong Kong. Comparison group consisted of 494 consecutive children attending a general child psychiatric clinic. SDQ and basic socio-demographic data were collected from parents and teachers. Reliability was determined by internal consistency and test-retest stability. Validity was assessed by the questionnaire's ability to discriminate between community and clinic samples, and ROC curves. Cutoff scores and their sensitivity, specificity, positive predictive value and negative predictive value were calculated.
Results: Our results confirm the questionnaire's reliability and validity. The total difficulties scale and hyperactivity subscale are potentially the most useful in discriminating between community and clinic children. The emotional subscale was relatively weaker, especially with respect to teachers' ratings. Of note also is that our normative scores are significantly higher than those reported in the West, highlighting once again the importance of examining a questionnaire's cultural applicability.
Conclusion: Our data support the use of the Chinese version of the SDQ, especially the total difficulties scale, as a screening instrument for psychiatric morbidities among children in Hong Kong.