Toplak, M. E., Sorge, G. B., Flora, D. B., Chen, W., Banaschewski, T., Buitelaar, J. K., Ebstein, R. P., Eisenberg, J., Franke, B., Gill, M., Miranda, A., Oades, R. D., Roeyers, H., Rothenberger, A., Sergeant, J. A., Sonuga-Barke , E. J. S., Steinhausen, H-C., Thompson, M., Tannock, R., Asherson, P., & Faraone, S. V.,

The hierarchical factor model of ADHD: Invariant across age and national groupings? Journal of Child Psychology and Psychiatry, 53, 292-303. doi: 10.1111/j.1469-7610.2011.02500.x.

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Our aim was to examine the factor structure of ADHD in a clinical sample of 1373 children and adolescents with ADHD and their 1772 unselected siblings recruited from different countries across a large age range (5-17 y).


a) Hierarchical and correlated factor analytic models were compared separately in the ADHD and sibling samples, across three different instruments and across parent & teacher informants. Specific consideration was given to factorial invariance analyses across different ages and different countries in the ADHD sample.

b) Children & adolescents with ADHD and their unselected siblings were assessed following recruitment from 7 European countries and Israel. ADHD symptom data came from a clinical interview with parents (PACS) & questionnaires from parents and teachers (Conners Parent and Teacher).

1 - A hierarchical general factor model with two specific factors best represented the structure of ADHD in both the ADHD & unselected sibling groups across informants and instruments.

2 - The model was robust & invariant with regard to age differences in the ADHD sample.

3 - The model was not strongly invariant across different national groups in the ADHD sample, likely reflecting severity differences across the different centers and no substantial differences in the clinical presentation of ADHD.


a) The results replicate and extend previous studies of a model with a unitary ADHD component and separable specific traits of inattention and hyperactivity / impulsivity.

b) The unique contribution of this study was finding support for this model across a large developmental and multi-national / multi-cultural sample & its invariance across ages

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