Dutch norms for the Strengths and Difficulties Questionnaire (SDQ) - parent form for children aged 2-18years

Background: Identification of children at risk for psychosocial problems is important to be able to provide supportive and tailored care at an early stage. Due to its brevity and wide age range, the Strengths and Difficulties Questionnaire (SDQ) Parent Form is an appropriate instrument for use in paediatric clinical practice as it facilitates assessment of psychosocial functioning from young childhood into adulthood. The aim of the present study was to provide Dutch normative data for the SDQ Parent Form. Methods: A sample of 1947 parents with children aged 2-18years was drawn from a large panel of a Dutch research agency, stratified on Dutch key demographics of the parents. The SDQ Parent Form assesses the child's Emotional symptoms, Conduct problems, Hyperactivity-Inattention, Peer problems and Prosocial behaviour. Summary scores can be calculated: Internalising, Externalising and Total difficulties. Internal consistency (Cronbach's alpha coefficient) and normative scores (mean, median, clinical cut-off scores) of the SDQ- Parent Form were calculated in four age-groups 2-3, 4-5, 6-11 and 12-18years. Gender differences were tested with independent t-tests. Results: A total of 1174 parents (60.3%) completed the SDQ. In the age-groups 2-3 and 4-5, norm scores are not available for Conduct problems and Peer problems due to insufficient internal consistency. In addition, in age-group 2-3, norm scores for Emotional symptoms and Internalising are not available because of insufficient internal consistency. In the age-groups 6-11 and 12-18, norm scores are available for all scales, with Cronbach's alpha coefficients 0.53-0.86. The comparison by gender revealed that boys had more behavioural problems than girls (0.000<p<0.048), most prevalent for Hyperactivity-Inattention, Peer Problems, Prosocial behaviour, Externalising and Total Difficulties. Conclusions: Dutch normative data by age-group and gender are now available for parent-reported SDQ scores in children aged 2-18years. Due to insufficient internal consistency, normative scores for 2-5year-old children could not be presented for several SDQ scales. Yet, the SDQ Total score provides a reliable indication of the psychosocial functioning of younger children. In case of high Total scores in children younger than 6years, alternatively to scale scores, the answers on the individual items could yield useful clinical information about the child's problems.