title: Psychometric behaviour of the strengths and difficulties questionnaire (SDQ) in the Spanish national health survey 2006.
abstract: BACKGROUND
  The Strengths and Difficulties Questionnaire (SDQ) is a tool to measure the risk for mental disorders in children. The aim of this study is to describe the diagnostic efficiency and internal structure of the SDQ in the sample of children studied in the Spanish National Health Survey 2006.
  
  
  METHODS
  A representative sample of 6,773 children aged 4 to 15 years was studied. The data were obtained using the Minors Questionnaire in the Spanish National Health Survey 2006. The ROC curve was constructed and calculations made of the area under the curve, sensitivity, specificity and the Youden J indices. The factorial structure was studied using models of exploratory factorial analysis (EFA) and confirmatory factorial analysis (CFA).
  
  
  RESULTS
  The prevalence of behavioural disorders varied between 0.47% and 1.18% according to the requisites of the diagnostic definition. The area under the ROC curve varied from 0.84 to 0.91 according to the diagnosis. Factor models were cross-validated by means of two different random subsamples for EFA and CFA. An EFA suggested a three correlated factor model. CFA confirmed this model. A five-factor model according to EFA and the theoretical five-factor model described in the bibliography were also confirmed. The reliabilities of the factors of the different models were acceptable (>0.70, except for one factor with reliability 0.62).
  
  
  CONCLUSIONS
  The diagnostic behaviour of the SDQ in the Spanish population is within the working limits described in other countries. According to the results obtained in this study, the diagnostic efficiency of the questionnaire is adequate to identify probable cases of psychiatric disorders in low prevalence populations. Regarding the factorial structure we found that both the five and the three factor models fit the data with acceptable goodness of fit indexes, the latter including an externalization and internalization dimension and perhaps a meaningful positive social dimension.Accordingly, we recommend studying whether these differences depend on sociocultural factors or are, in fact, due to methodological questions.
authors.affiliation: Teaching Unit of Psychiatry and Psychological Medicine, Department of Medicine, University of Valencia, Valencia, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Gómez-Beneyto
authors.forename: Andreu
authors.initials: A
authors.lastname: Nolasco
authors.forename: Joaquín
authors.initials: J
authors.lastname: Moncho
authors.forename: Pamela
authors.initials: P
authors.lastname: Pereyra-Zamora
authors.forename: Nayara
authors.initials: N
authors.lastname: Tamayo-Fonseca
authors.forename: Mikel
authors.initials: M
authors.lastname: Munarriz
authors.forename: José
authors.initials: J
authors.lastname: Salazar
authors.forename: Rafael
authors.initials: R
authors.lastname: Tabarés-Seisdedos
authors.forename: Manuel
authors.initials: M
authors.lastname: Girón
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis* / Q000453:epidemiology; D011594:Psychometrics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013030:Spain; D011795:Surveys and Questionnaires