Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder that is characterized by two distinct behaviors: persistent deficits in social interaction and communication, and the presence of restricted or repetitive behaviors, interests or activities. It is predominantly diagnosed in males, with boys having a diagnosis of ASD 3 to 4 times more often than girls (e.g. Baird et al., 2006). Children with ASD can range from non-verbal to verbal however with a ‘robotic-like’ tone of voice or in an exaggerated singsong (Child Mind Institute, New York). The outlined defining symptoms must be present across multiple contexts and be identifiable in the early developmental period, typically recognized in the first two years of life, and are required to cause clinically significant impairment in social, occupational, and other areas of adaptive functioning.
Alongside the triad of deficits primarily associated with ASD, deficits in social interaction and communication; non-verbal communicative behaviours; and understanding of relationships, another prominent feature characterizing ASD is the presence of restricted or repetitive behaviors, typically in the form of: 1) stereotyped actions, use of objects or speech, which are repeated or fixated upon to the point of distract- ion and interference in daily routine; 2) an insistence on sameness, rigid thinking patterns, and difficulty with transitions; 3) highly restricted and intense interests; and 4) hyper- or hypo-reactivity to sensory input or atypical interests in the sensory aspects of the environment.
Under the new diagnostic guidelines for the disorder, the psychiatric community shifts in the way they conceptualize autism as reflected in the DSM-5 guidelines. The revision of the triad of impairments (Wing & Gould, 1979) that characterize ASD into a dyad was implemented to create more accurate diagnoses and treatment. To enhance diagnostic precision, modifications were made to the autism criteria, specifically in symptom inclusion, age of onset, and number of symptoms required for diagnosis (Matson & Kozlowski, 2011). As a result of this, previous subgroups of Autism, Asperger’s Syndrome (AS), childhood disintegrative disorder (CDD) and pervasive developmental disorder- not otherwise specified (PDD-NOS) were removed from diagnostic guidelines, and are now collected under a uni-dimensional disorder that presents along a spectrum of symptoms and behaviors of varying severity.
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