Abstract:
Autism Spectrum Disorder (ASD) or Autism (MIM 209850) is a complex
heterogeneous neurodevelopmental disorder. It manifests before the age of three (1).
Although autism can be diagnosed at any age, it is described as a “developmental
disorder” because symptoms generally appear in the first two years of life. Diagnostic
and Statistical Manual of Mental Disorders (DSM-5) is a diagnostic guide created by
the American Psychiatric Association that healthcare providers use to diagnose
different mental disorders/illnesses. People with ASD often have featured early onset
dysfunctions in verbal and non-verbal communication, impairments in social
interaction and repetitive and stereotyped behaviours and interests (2).
Autism is known as a “spectrum” disorder because there is wide variation in the type
and severity of symptoms that individuals experience. Individuals of all genders,
races, ethnicities, and economic backgrounds can be diagnosed with ASD. Although
ASD can be a lifelong disorder, treatments and services can improve a person’s
symptoms and daily functioning. The previous version of the DSM, i.e. the DSM-4,
included autism under the umbrella of pervasive developmental disorder and divided
autism into five distinct categories ranging from Asperger's syndrome (often used to
describe mild or high-functioning autism) to autistic disorder, which indicated severe
autism. The 5 diagnostic ranges include autistic disorder, Asperger’s disorder,
Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS), Rett’s
disorder and Childhood Disintegrative Disorder (CDD). But the recent version of the
DSM, i.e. DSM-V combines all of these into a spectrum of single diagnosis called
autism spectrum disorder with different levels of severity (Fig.1) (3).
