What is Autism?

The term “autism” can refer to a whole range of disorders (known as PDDs or Pervasive Developtmental Disorders) characterized by difficulty socializing and communicating one’s needs. That range, often referred to as the autism spectrum, includes autism, Asperger’s, and PDD-NOS (Pervasive Developmental Disorder – Not Otherwise Specified). The term Autism Spectrum Disorder (ASD) refers to any of these conditions.


Autistic disorder, sometimes referred to as classical ASD or autism, is the most severe form of ASD. Children with autism generally have difficulties with verbal and nonverbal communication and exhibit repetitive patterns of behavior. An infant with autism may be unresponsive to others or tend to focus on one object for an extended amount of time. A child with autism may be late in learning to speak and may seem disinterested in social interaction.

Asperger’s Syndrome

Asperger’s was only classified as a subtype of Pervasive Developmental Disorders in 1994 – prior to this, people with the disorder were diagnosed with “mild” or “high-functioning” autism. Children who show a lesser degree of the communicative and social impairment characteristic of classical autism may be diagnosed with Asperger’s Syndrome. These children typically do not have language delays and tend to have average or above-average intellect. They might demonstrate that intellectual acumen through an encyclopedic knowledge of a favorite subject, for instance, or a rich vocabulary atypical for their age.


Pervasive Developmental Disorder – Not Otherwise Specified (PDD-NOS) is a diagnosis given to a child that exhibits certain autistic behaviors but cannot be placed in a specific category on the autism spectrum. It’s also possible for a very young child to receive this diagnosis if it’s clear there are developmental delays, but it’s still too early to definitively diagnose autism.

How common are Autism Spectrum Disorders?

Autism occurs in all ethnic and socioeconomic groups and affects every age group. A 2009 report released by the CDC stated that autism occurs in 1 out of every 110 babies born in the United States, and boys are 4 to 5 times more likely to have an ASD than girls. Scientists believe male hormones may suppress a gene that those with autism express less than those without it, although more research is needed before any definitive conclusions are reached.

The number of autism diagnoses has rapidly increased over the years, but some studies have suggested that the rise is due to better diagnostic techniques and broader definitions of autism, not an actual increase in the prevalence of the disease. Nonetheless, the CDC states that “a true increase in the risk for children to develop ASD symptoms cannot be ruled out.”

And here are 10 more facts about autism and Asperger’s that you probably didn’t know.

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One thought on “Autism-Spectrum Disorders: A guide to ASD causes, treatment, support

  1. A subtext here is the issue of mercury, which has been used as a preservative in some vaccines (though most pediatric vaccines no longer contain it). Some parents connect mercury, vaccines and autism, and they say chelation can remove mercury and treat autism. But the public health community roundly rejects the autism-mercury connection, citing multiple studies.

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