AbstractAutism spectrum disorder (ASD) is a behaviorally defined neurodevelopmental disorder associated with the presence of social-communication deficits and restricted and repetitive behaviors. In the latest conceptualization of ASD, these two behavioral dimensions represent the core defining features of ASD, whereas associated dimensions, such as intellectual and language ability, provide a means for describ-ing the ASD heterogeneity. In addition, the characterization of ASD subgroups, defined by the presence of known medical, genetic, or other psychiatric disorders, furthers our under-standing of ASDheterogeneity. This paper reviews the history of autism, describes its core defining features, and provides an overviewof the clinically and etiologically relevant subgroups that add to the complexity of this condition. KeywordsAutism.
Autismspectrumdisorder.DSM-5. ICD-11 .ADHD.Anxiety.Depression.Disruptive behavior.Catatonia. Kanner. Asperger.Pervasive developmental disorder. Dimension. Subtype. Specifier