Overview of Autism

Autism (referred to in DSM IV as autistic disorder) is a Pervasive Developmental Disorder (PDD). Related developmental disorders defined in the DSM-IV are Asperger’s Disorder and Pervasive Developmental Disorder – Not Otherwise Specified (PPD-NOS). Together these three are sometimes called Autistic Spectrum Disorder (ASD), or simply autism. In the proposed DSM-V, the collective diagnosis for Autism, PDD, and Asperger Syndrome will be Autism Spectrum Disorders. Autism Spectrum Disorders (ASDs) have an estimated prevalence of 1 in 88 children in the United States.[1]

In concept, the diagnosis of autism has not changed since it was first formulated by Leo Kanner in 1943: abnormal development of social reciprocity, abnormal development of language, especially as it is used for communicating with other persons, and desire for sameness, as seen in repetitive rituals or intense circumscribed interests.[2] Autism did not become a diagnostic entity in its own right until the Diagnostic and Statistical Manual (DSM)-III was published in 1980.[3]

The current DSM-IV distinguishes between Autistic Disorder and other variants such as Asperger’s Disorder. Distinctions between these Pervasive Developmental Disorders in the DSM-IV essentially rely on retrospective analysis of differences in the developmental timing and the severity or profile of autistic signs and symptoms.[4] However, there is general agreement on the three primary/core diagnostic criteria for autism:- social impairment, communication impairment, and the presence of repetitive behaviors and interests.[5]

Figure 1. Core Symptoms (Center, necessary for diagnosis) and Associated Symptoms (Periphery, not required)

Although there is no cure, medical treatments for symptoms of ASDs comprise a variety of pharmacologic agents including antipsychotics, psychostimulants, and selective serotonin reuptake inhibitors (SRIs) that are generally intended to treat common comorbidities of ASDs. Modalities such as therapeutic diets, supplements, hormonal supplements, immunoglobulin, hyperbaric oxygen, and chelating agents also have been employed to treat ASDs symptoms. There remains an unmet medical need for an effective pharmacotherapy to treat the core symptoms of this serious disorder given that there are no approved marketed drugs for this indication. Only two medications have received FDA approval to treat irritability (an  associated, not “core”, symptom of autism, see the figure above) in children with autism.

[1] Prevalence of the Autism Spectrum Disorders (ASDs) in Multiple Areas of the United States, 2004 and 2006. Atlanta: Centers for Disease Control and Prevention; 2009.

[2] Kanner L.  (1943)  Autistic disturbances of affective contact.   Nervous Child 2:217-250.

[3] Tidmarsh, L. and Volkmar, F.R.  (2003)  Diagnosis and epidemiology of Autism Spectrum Disorders. Can J Psychiatry 48:517-525.

[4] Tidmarsh, L. and Volkmar, F.R.  (2003)  Diagnosis and epidemiology of Autism Spectrum Disorders. Can J Psychiatry 48:517-525.

[5] Tager-Flusberg, H., Joseph, R. and Folstein, S.  (2001)  Current directions in research on autism.   Ment Retard Dev Disabil Res Rev 7:21–29.