title: Structural brain imaging correlates of ASD and ADHD across the lifespan: a hypothesis-generating review on developmental ASD-ADHD subtypes.
abstract: We hypothesize that it is plausible that biologically distinct developmental ASD-ADHD subtypes are present, each characterized by a distinct time of onset of symptoms, progression and combination of symptoms. The aim of the present narrative review was to explore if structural brain imaging studies may shed light on key brain areas that are linked to both ASD and ADHD symptoms and undergo significant changes during development. These findings may possibly pinpoint to brain mechanisms underlying differential developmental ASD-ADHD subtypes. To this end we brought together the literature on ASD and ADHD structural brain imaging symptoms and particularly highlight the adolescent years and beyond. Findings indicate that the vast majority of existing MRI studies has been cross-sectional and conducted in children, and sometimes did include adolescents as well, but without explicitly documenting on this age group. MRI studies documenting on age effects in adults with ASD and/or ADHD are rare, and if age is taken into account, only linear effects are examined. Data from various studies suggest that a crucial distinctive feature underlying different developmental ASD-ADHD subtypes may be the differential developmental thinning patterns of the anterior cingulate cortex and related connections towards other prefrontal regions. These regions are crucial for the development of cognitive/effortful control and socio-emotional functioning, with impairments in these features as key to both ASD and ADHD.
authors.affiliation: Department of Psychiatry, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands. n.lambregts-rommelse@psy.umcn.nl.|Karakter, Child and Adolescent Psychiatry University Center, Nijmegen, The Netherlands. n.lambregts-rommelse@psy.umcn.nl.
authors.forename: Nanda
authors.initials: N
authors.lastname: Rommelse
authors.affiliation: Karakter, Child and Adolescent Psychiatry University Center, Nijmegen, The Netherlands.|Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Jan K
authors.initials: JK
authors.lastname: Buitelaar
authors.affiliation: Department of Psychiatry, Interdisciplinary Center of Psychopathology and Emotion Regulation (ICPE) & Research School of Behavioral and Cognitive Neuroscience, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Catharina A
authors.initials: CA
authors.lastname: Hartman
mesh_terms: D001289:Attention Deficit Disorder with Hyperactivity / Q000000981:diagnostic imaging*; D000067877:Autism Spectrum Disorder / Q000000981:diagnostic imaging*; D001921:Brain / Q000000981:diagnostic imaging* / Q000254:growth & development*; D006801:Humans; D059906:Neuroimaging
keywords: Adolescence; Adults; Anterior cingulate cortex; Attention-deficit/hyperactivity disorder; Autism spectrum disorder; Brain; Comorbidity; Life span; MRI; Prefrontal