Autism spectrum disorder (ASD) and autism are both general terms for a group of complex disorders of brain development. These disorders are characterized by difficulties in social interaction, verbal and nonverbal communication and repetitive behaviors.
Autism appears to have its roots in early brain development. The most obvious signs of autism and symptoms of autism tend to emerge between 2 and 3 years of age. Both children and adults with autism typically show difficulties in verbal and non-verbal communication, social interactions, and leisure or play activities.
ASD occurs in all racial, ethnic, and socioeconomic groups. However, it is about five times more common among boys than among girls. CDC estimated that about 1 in 68 children (2014 CDC) had been identified with an autism spectrum disorder.
There are three different types of Autism Spectrum Disorders:
1. Autistic Disorder (“classic” autism)
This is what most people think of the word “autism.” People with autistic disorder usually have significant language delays, social and communication challenges, and unusual behaviors and interests. Many people with autistic disorder also have intellectual disability.
2. Asperger Syndrome
People with Asperger syndrome usually have some milder symptoms of autistic disorder. They might have social challenges and unusual behaviors and interests. However, they typically do not have problems with language or intellectual disability.
3. Pervasive Developmental Disorder (PDD)
People who meet some of the criteria for autistic disorder or Asperger syndrome, but not all, may be diagnosed with PDD. People with PDD usually have fewer and milder symptoms than those with autistic disorder.