Convergence and divergence Comparing symptom expression of and treatment for (parents of) children with ASD and those with ADHD

Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) appear to have several overlapping features in terms of etiology, underlying mechanisms, and symptom expression. This raises the question of whether it is relevant to distinguish these classifications in school-aged children. Therefore, in this dissertation, differences between core and comorbid problems of school-aged children with ASD and those with ADHD – as well as their parents – were explored. Also, it was investigated whether (parents of) children with ASD and those with ADHD differed with respect to received treatment. Furthermore, a subscale to screen for ASD – consisting of separate items of the school-age version of the Child Behavior Checklist (CBCL) – was constructed and validated. Finally, it was examined whether it is feasible to provide a transdiagnostic Social Skills Training (SST) to a group of middle school-aged children and their parents.
The results of this dissertation revealed that, statistically, school-aged children with ASD and those with ADHD can be distinguished with reference to their core symptoms. Both groups experienced relatively high levels of comorbid problems, although children with ASD seemed to be somewhat more impaired. Regarding their parents, hardly any group differences were found. Besides, the types and hours of treatment for the ASD and ADHD group largely overlapped. Additionally, the groups seemed to benefit equally from this treatment. Moreover, the results showed that the constructed ASD subscale had a similar screening potential to that of the existing DSM-oriented subscales. Also, the preliminary effects of the SST were promising, confirming its feasibility.