title: Autism spectrum disorder and attention-deficit/hyperactivity disorder in early childhood: A review of unique and shared characteristics and developmental antecedents.
abstract: Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) have overlapping characteristics and etiological factors, but to which extent this applies to infant- and preschool age is less well understood. Comparing the pathways to ASD and ADHD from the earliest possible stages is crucial for understanding how phenotypic overlap emerges and develops. Ultimately, these insights may guide preventative and therapeutic interventions. Here, we review the literature on the core symptoms, temperament and executive function in ASD and ADHD from infancy through preschool age, and draw several conclusions: (1) the co-occurrence of ASD and ADHD increases with age, severity of symptoms and lower IQ, (2) attention problems form a linking pin between early ASD and ADHD, but the behavioral, cognitive and sensory correlates of these attention problems partly diverge between the two conditions, (3) ASD and ADHD share high levels of negative affect, although the underlying motivational and behavioral tendencies seem to differ, and (4) ASD and ADHD share difficulties with control and shifting, but partly opposite behaviors seem to be involved.
authors.affiliation: Karakter Child and Adolescent Psychiatry University Center, Nijmegen, The Netherlands. Electronic address: Janne.Visser@radboudumc.nl.
authors.forename: Janne C
authors.initials: JC
authors.lastname: Visser
authors.affiliation: Karakter Child and Adolescent Psychiatry University Center, Nijmegen, The Netherlands; Radboud University Medical Center, Donders Institute for Brain, Cognition and Behavior, Department of Psychiatry, Nijmegen, The Netherlands.
authors.forename: Nanda N J
authors.initials: NN
authors.lastname: Rommelse
authors.affiliation: Karakter Child and Adolescent Psychiatry University Center, Nijmegen, The Netherlands; Radboud University Medical Center, Donders Institute for Brain, Cognition and Behavior, Department of Cognitive Neuroscience, Nijmegen, The Netherlands; King's College London, Medical Research Council Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, London, UK.
authors.forename: Corina U
authors.initials: CU
authors.lastname: Greven
authors.affiliation: Karakter Child and Adolescent Psychiatry University Center, Nijmegen, The Netherlands; Radboud University Medical Center, Donders Institute for Brain, Cognition and Behavior, Department of Cognitive Neuroscience, Nijmegen, The Netherlands.
authors.forename: Jan K
authors.initials: JK
authors.lastname: Buitelaar
mesh_terms: D001288:Attention; D001289:Attention Deficit Disorder with Hyperactivity; D000067877:Autism Spectrum Disorder; D002675:Child, Preschool; D056344:Executive Function; D006801:Humans; D013694:Temperament
keywords: ADHD; ASD; Attention; Autism; Early developmental mechanisms; Early developmental pathways; Executive function; Infant; Preschool age; Temperament