Cognitive endophenotypes of attention deficit/hyperactivity disorder and intra-subject variability in patients with autism spectrum disorder

• Published in: Biological psychology Vol. 118; pp. 25 - 34
• Main Authors: Biscaldi, M., Bednorz, N., Weissbrodt, K., Saville, C.W.N., Feige, B., Bender, S., Klein, C.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.07.2016
• Subjects: ADHD; Attention; Attention Deficit Disorder with Hyperactivity - complications; Attention Deficit Disorder with Hyperactivity - psychology; Attention deficit/hyperactivity disorder; Autism; Autism Spectrum Disorder - complications; Autism Spectrum Disorder - psychology; Autism spectrum disorders; Case-Control Studies; Child; Cognition; Endophenotype; Endophenotypes; Female; Humans; Inhibition; Inhibition (Psychology); Intra-subject variability; Male; Memory, Short-Term; Temporal processing; Working memory; Autism spectrum disorders; Autism; ADHD; Intra-subject variability; Temporal processing; Inhibition; Working memory; Attention deficit/hyperactivity disorder; Endophenotype
• DOI: 10.1016/j.biopsycho.2016.04.064
• ISSN: 0301-0511; 1873-6246

•We investigate whether cognitive endophenotypes of ADHD and increased intra-subject variability can be found in children with autism spectrum disorder.•This is the first study to compare autism with or without ADHD comorbidity using a battery of rather diverse tests of (presumed) endophenotypes of ADHD.•On the basis of a broad test battery, patients with autism show an inconsistent increase of ISV that is almost exclusively driven by the subgroup with ADHD comorbidity. Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) have previously been studied mainly in isolation from each other. However the two conditions may be aetiologically related and thus show overlap in aetiologically relevant functions. In order to address this question of potential aetiological overlap between ADHD and ASD, the present study set out to investigate putative endophenotypes of ADHD in N=33 typically developing (TD) children and N=28 patients with ASD that were (ASD+) or were not (ASD−) co-morbid for ADHD. With regard to both the cognitive endophenotype candidates (working memory, inhibition, temporal processing) and intra-subject variability (ISV) the pattern of abnormalities was inconsistent. Furthermore, the overall profile of ASD-TD differences was extremely similar to the pattern of differences between the ASD+ and ASD− sub-groups, suggesting that any abnormalities found were due to the comorbid ASD subgroup. This held in particular for ISV, which did not show in patients with ASD the task-general increase that is common in ADHD samples. Altogether, the present results do not support the hypothesis of aetiological overlap between ASD and ADHD.