The Strengths and Difficulties Questionnaire (SDQ): the factor structure and scale validation in U.S. adolescents

The Strengths and Difficulties Questionnaire (SDQ) is one of the most commonly used instruments for screening psychopathology in children and adolescents. This study evaluated the hypothesized five-factor structure of the SDQ and examined its convergent validity against comprehensive clinical diagnostic assessments. Data were derived from the National Comorbidity Survey - Adolescent Supplement (NCS-A), a nationally representative sample of U.S. adolescents aged 13 to 18 years. Parents/parent surrogates (n=6,483) was asked to complete a self-administered questionnaire including the SDQ and DSM-IV comprehensive diagnostic information on the participating adolescents. Confirmatory factor analysis (CFA) was conducted to assess the factor structure of the SDQ. The five-factor solution of the SDQ (including emotional, conduct, hyperactivity-inattention, peer relationship, and prosocial) provided a satisfactory fit to the data, and was invariant across sex, age, race/ethnicity and income subgroups. SDQ scores predicted a significantly increased probability of meeting criteria for a DSM-IV disorder, with better prediction for behavior disorders than for mood disorders. Decreasing the SDQ cutoffs to the 80th percentile significantly increased the sensitivity from 39% to 63% for the SDQ Total Difficulties Score, with an expected decrease in specificity from 93% to 87%. This work confirms the five-factor structure of the SDQ in an ethnically and sociodemogrpahically diverse community sample of adolescents. Our findings strengthen empirical evidence for the use of the parent-reported SDQ as a screening tool for DSM-IV behavioral and emotional disorders in adolescents identified in the general population.