Autism spectrum disorder: underlying neurobiology.

Abstract

Over the recent years, a lot of progress has been made on eliciting the underlying neurobiology of Autism spectrum disorder (ASD). This severe and disabling neurodevelopmental disorder is characterized by pervasive impairments in social interaction, communication, and repetitive or stereotyped behaviour, and is associated with a significant burden not only to the affected children and their families but also to the society as a whole (Lavelle et al. 2014). Fuelled by strong public and private support for ASD research, especially in the US, large scale genetic, but also phenotypic studies have been performed. These studies have indicated a continuum of the autism specific social interaction and communication abilities as well as stereotyped behaviours and special interests, which cross the old diagnostic boundaries of DSM-IV TR and ICD-10. This continuum idea has now been integrated in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Autism spectrum disorder (ASD) now comprises former DSM-IV TR diagnoses autism, Asperger’s Disorder, Childhood Disintegrative Disorder, and Pervasive Developmental Disorder—not otherwise specified (American Psychiatric Association 2000; American Psychiatric Association 2013) which are roughly comparable to the ICD-10 diagnoses autism, Asperger Syndrome, Childhood Disintegrative Disorder, and atypical autism (World Health Organization 1992). Over the past years, a number of research studies have already been performed in this integrated way investigating combined samples. With regard to current neurobiological research in ASD, the following core topics and research questions are starting to emerge: (1) What are the specific characteristics of ASD compared to other child psychiatric disorders? This question is specifically relevant for the question of differential diagnosis and differential treatment of all ASD as a group versus other child psychiatric disorders. (2) Within ASD, can we describe more homogeneous neurobiologically defined subtypes, which may share the same aetiology? This question is specifically relevant to provide a basis for research on specific treatment options for some children with ASD who share an underlying neurobiology, as has been described, for example, for Fragile-X-Syndrome (Berry-Kravis et al. 2012). This special issue of the Journal of Neural Transmission combines a comprehensive collection of original and review articles trying to answer these two core research questions.