Seeing the Possible:
Understanding Autism Spectrum Disorders

Under the umbrella of Pervasive Developmental Disorders, there are five disorders that share distinct characteristics unique to classify and identify an Autism Spectrum Disorder (ASD):

What is Autistic Disorder?

The criteria for Autistic Disorder are qualitative or highly noticeable impairments in social interaction, communication, speech and language skills, play and imagination appropriate to developmental age, and restricted repetitive and stereotyped behaviors or sequences of behavior, interests and activities or routines that are difficult to change or modify (DSM-IV-TR, 2000). In many cases, mental retardation may also be present with Autistic Disorder ranging from mild to severe and profound (DSM-IV-TR, 2000). Diagnostic characteristics usually emerge before age 3.

What is Asperger's Disorder?

A diagnosis of Asperg's Disorder (AD), also known as Asperger's Syndrome, is given when there is a severe and sustained impairment in social interaction, and a development of restricted and repetitive patterns of behavior, interests and activities that causes significant impairment in social, occupational and/or other important areas of functioning (DSM-IV-TR, 2000). For example, the child may know and express everything about trains, ceiling fans, historical dates and integral details pertaining to his/her interests, but does not know how to give and take in conversations or relate to information the communicative partner expresses. With AD, there are no clinically significant delays or impairments in language development or cognitive development and mental retardation is not present, although some very mild mental retardation cases have been reported (DSM-IV-TR, 2000). Many children are diagnosed with Attention Deficit/Hyperactivity Disorder prior to a diagnosis of AD, and AD has been associated with other conditions such as depressive disorders (DSM-IV-TR, 2000).


With AD, the social disability becomes more obvious over time and individuals may learn how to use areas of strengths to compensate for areas of weaknesses such as memorizing social responses to use in social situations. Asperger's Disorder is diagnosed 5 times more in males than in females (DSM-IV-TR, 2000).

What is Rett's Syndrome?

Rett's Syndrome is much less common than Autistic Disorder and has only been reported in females (DSM-IV-TR, 2000). Prenatal and perinatal development is normal for the first 5 months. However, between 5 and 48 months, the child's head growth decelerates, and the child's purposeful hand skills are replaced with repetitive hand wringing or hand washing type movements (DSM-IV-TR, 2000). A few years after the onset of Rett's Syndrome, there is a decreased interest in the child's social environment, problems develop in gait and/or trunk movements along with severe psychomotor retardation, and severe impairments in expressive and receptive language development emerge (DSM-IV-TR, 2000).

What is Childhood Disintegrative Disorder?

After a period of at least two years of typical development in all areas of functioning, the child develops a severe and clinically significant loss of skills in at least two of the following areas: expressive or receptive language, social skills and/or adaptive behavior, loss of bladder or bowl control, play skills, and/or motor skills (DSM-IV-TR, 2000). The characteristics of Childhood Disintegrative Disorder (CDD) resemble Autistic Disorder but onset of CDD can be up to age 10 and severe mental retardation is usually present. Other complications may include seizure disorder and abnormal EEG's (DSM-IV-TR, 2000). This disorder is very rare and recent data suggest that the condition is more common among males than females (DSM-IV-TR, 2000).

What is Pervasive Developmental Disorder Not Otherwise Specified?

Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS) or Atypical Autism is diagnosed when all of the criteria for the other four pervasive developmental disorders are not met, as well as criteria for Schizophrenia, Schizotypal Personality Disorder, or Avoidant Personality Disorder are not met (DSM-IV-TR, 2000). There may be deviations in developmental milestones or sequences that are atypical but not clinically significant to give a diagnosis of anotherautism spectrum disorder.

Each of these disorders has specific diagnostic criteria which have been outlined in the American Psychiatric Association's Diagnostic & Statistical Manual of Mental Disorders (DSM-IV-TR, 2000).


Today, one out of every 68 children are diagnosed with ASDs, with some diagnosed as young as 18 months old. ASDs cross all racial, ethnic, and socioeconomic lines and affect thousands of Americans throughout the U.S. Rates of children diagnosed have rapidly increased, with rates three to four times higher than during the 1970s.