Update on Autism

Autism is demanding increased attention by professional and lay audiences; prevalence seems to be increasing. There are differing opinions about whether the increase is due to greater recognition and reporting, diagnostic expansion and substitution, or increasing acceptability. On the other hand, the increase may be a consequence of environmental toxins or infectious and immune vulnerability and epigenetics or perhaps a combination of social and environmental factors.

Clearly, autism has a large genetic component and multiple genes are involved in various combinations. Nevertheless, the prevalence of autism in the United States and in other countries has increased exponentially; this trend would not happen with a purely genetic disorder. Most autism researchers accept a theory of etiology that starts with a genetic neurodevelopmental vulnerability combined with an environmental stressor through such epigenetic processes as immune function.¹

Increasingly, researchers and clinicians refer to autism to describe a wide variety of phenotypes that start with genes and gene expression and range through a variety of metabolic functions to symptoms that cluster diagnostically but have a great deal of individuality. Symptoms can range from mild to severe and may be associated with mental retardation; GI and neurological involvement; and behavioral, emotional, cognitive, and whole body pathology.²

Here we discuss diagnostic assessment and classification, co-occurring or comorbid psychiatric disorders and their differential diagnosis, the medical workup, and possible medical comorbidities. We also review a model for psychosocial treatment as well as psychopharmacological and alternative treatments. We conclude with a brief look at the future of research and treatment.

Diagnostic assessment and classification

The term “autism (or autistic) spectrum disorder” (ASD) is likely to be replaced with “pervasive developmental disorder” in DSM-5. ASD is a collection of neurodevelopmentally based conditions of social and communicative impairments, each with varying severity and broadness of expression.

Autism was originally described by Leo Kanner in the early 1940s and termed “early infantile autism” of unknown etiology. By the 1960s, work on high concordance of autism in monozygotic twins and lower concordance in dizygotic twins and siblings led to the present-day understanding of ASD as a developmental and neurobiological condition with heterogeneous genetic and possible epigenetic triggers.

Diagnosis of ASD remains an empirical and behavioral procedure with no clear or single biological marker or assay. This has made reliable and valid diagnosis problematic: signs of ASD selected for inclusion in DSM have had fairly high diagnostic sensitivity but often poor specificity.^3-5 Symptoms of ASD overlap with those of other neurodevelopmental disorders. Accurate differential diagnosis and diagnosis of comorbid conditions in ASD are therefore difficult.

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