Examining the Overlap Between ADHD and Autism Spectrum Disorder (ASD) Using Candidate Endophenotypes of ADHD

G Salunkhe; K Weissbrodt; B Feige; C W N Saville; A Berger; N M Dundon; S Bender; N Smyrnis; A Beauducel; M Biscaldi; C Klein

doi:10.1177/1087054718778114

Examining the Overlap Between ADHD and Autism Spectrum Disorder (ASD) Using Candidate Endophenotypes of ADHD

J Atten Disord. 2021 Jan;25(2):217-232. doi: 10.1177/1087054718778114. Epub 2018 Jun 13.

Authors

G Salunkhe¹, K Weissbrodt¹, B Feige², C W N Saville³, A Berger⁴, N M Dundon¹, S Bender⁵, N Smyrnis⁶, A Beauducel⁷, M Biscaldi¹, C Klein^{1

5}

Affiliations

¹ Department of Child and Adolescent Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, University of Freiburg, Germany.
² Department of Psychiatry and Psychotherapy, Medical Faculty, University of Freiburg, Germany.
³ School of Psychology, Bangor University, UK.
⁴ Department of Psychology and Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer Sheva, Israel.
⁵ Department of Child and Adolescent Psychiatry, Medical Faculty, University of Cologne, Germany.
⁶ Department of Psychiatry, National and Kapodistrian University of Athens, Eginition Hospital, Greece.
⁷ Department for Research Methods, Diagnostics and Evaluation, Rheinische Friedrich-Wilhelms-Universität, Bonn, Germany.

PMID: 29896994
DOI: 10.1177/1087054718778114

Abstract

Objective: Recent discussions of aetiological overlap between ADHD and Autism Spectrum Disorder (ASD) require comparative studying of these disorders.

Method: We examined performance of ASD patients with (ASD+) and without (ASD-) comorbid ADHD, ADHD patients, and controls for selected putative endophenotypes of ADHD: Intrasubject Variability (ISV) of reaction times, working memory (WM), inhibition, and temporal processing.

Results: We found that patients with ADHD or ASD+, but not ASD-, had elevated ISV across the entire task battery and temporal processing deficits, and that none of the groups were impaired in WM or inhibition. High levels of ISV and generally poor performance in ASD+ patients were only partially due to additive effects of the pure disorders.

Conclusion: Overall, we conclude that, within our limited but heterogeneous task battery, ISV and temporal processing deficits are most sensitive to ADHD symptomatology and that controlling for ADHD comorbidity is mandatory when assessing ISV in autism.

Keywords: endophenotypes; intrasubject variability; response inhibition; temporal reproduction; working memory.

MeSH terms

Attention Deficit Disorder with Hyperactivity* / epidemiology
Autism Spectrum Disorder*
Comorbidity
Endophenotypes
Humans
Memory, Short-Term
Reaction Time