PDD Symptoms in ADHD, an Independent Familial Trait?

Abstract

The aims of this study were to investigate whether subtle PDD symptoms in the context of ADHD are transmitted in families independent of ADHD, and whether PDD symptom familiality is influenced by gender and age. The sample consisted of 256 sibling pairs with at least one child with ADHD and 147 healthy controls, aged 5-19 years. Children who fulfilled criteria for autistic disorder were excluded. The Children's Social Behavior Questionnaire (CSBQ) was used to assess PDD symptoms. Probands, siblings, and controls were compared using analyses of variance. Sibling correlations were calculated for CSBQ scores after controlling for IQ, ADHD, and comorbid anxiety. In addition, we calculated cross-sibling cross-trait correlations. Both children with ADHD and their siblings had higher PDD levels than healthy controls. The sibling correlation was 0.28 for the CSBQ total scale, with the CSBQ stereotyped behavior subscale showing the strongest sibling correlation (r=0.35). Sibling correlations remained similar in strength after controlling for IQ and ADHD, and were not confounded by comorbid anxiety. Sibling correlations were higher in female than in male probands. The social subscale showed stronger sibling correlations in elder than in younger sibling pairs. Crosssibling cross-trait correlations for PDD and ADHD were weak and not-significant. The results confirm that children with ADHD have high levels of PDD symptoms, and further suggest that the familiality of subtle PDD symptoms in the context of ADHD is largely independent from ADHD familiality.

Autism spectrum disorder symptoms in children with ADHD: A community-based study

“…Our results are also consistent with Kochhar et al's (2011b) finding that 28% of clinically referred children with ADHD (n = 30) had an SCQ total score above the clinical cut-off. These results confirm that children with ADHD from community-based samples have greater ASD symptoms than non-ADHD controls, consistent with previous findings in clinical samples (Nijmeijer, Hoekstra et al, 2009;Nijmeijer, Minderra, et al, 2008).…”

Integrating Autism-Related Symptoms into the Dimensional Internalizing and Externalizing Model of Psychopathology. The TRAILS Study

“…The CSBQ differentiates between (DSM-IV based) autism, PDD-NOS and ADHD, with decreasing scores for these three conditions, respectively (Hartman et al 2006). It has proven useful in populations other than ASD such as ADHD for characterizing subthreshold ASD problems (Nijmeijer et al 2008) and delinquent groups ('t Hart-Kerkhoffs, Jansen, Doreleijers, Vermeiren, Minderaa, Geluk et al 2012). The validity of the CSBQ also follows from genetic (Nijmeijer et al 2010), neurocognitive (Blijd-Hoogewys, van Geert, Serra, andGeurts, Luman, and van Meel 2008;Rommelse et al 2009) and behavioral (de Bildt et al 2005;Jaspers et al 2013) studies.…”

Developmental associations between traits of autism spectrum disorder and attention deficit hyperactivity disorder: a genetically informative, longitudinal twin study

“…Findings from family studies are inconsistent. Nijmeijer et al (2009) reported that ADHD and traits of ASD were genetically independent of one another. Conversely, Mulligan et al (2009) reported that 56 % of the phenotypic correlation between ADHD and ASD could be attributed to shared familial influences.…”