Etiological Theories of Autism Spectrum Disorder:
A Review of the Literature
Nova Southeastern University
Abstract
Within the last twenty years, the amount of empirical research regarding the possible cause(s) and risk factors for Autism Spectrum Disorder (ASD) has increased (Lai et al., 2014). According to the United States Centers for Disease Control and Prevention (CDC), ASD is currently identified in approximately 1 out of 68 children living in the United States, compared to 1 in 10,000 children in 1980 (Baio, 2014). The rise in ASD prevalence highlights the need to continue research into etiology, risk factors, and effective treatments. Purpose: This paper is a critical review of current scientific studies that have focused on the ASD population about etiology of the disorder, susceptibility, and prevalence. Theories and factors that appear to influence or predict ASD outcome are reviewed. Method: Twenty-two research articles published between January 1, 2009, and November 1, 2014, in scientific, peer-reviewed journals were retrieved from the following electronic databases: ProQuest, CINAHL Complete, and Cochrane Database of Systematic Reviews. The articles were evaluated for risk of bias. Results: Recent findings suggest autism is a disorder caused by interplay of multiple genetic, epigenetic and environmental factors.
Keywords: Autism, ASD, Autism Spectrum Disorder; in combination with: Etiology and/or Cause, Genetic Risk Factors,
Autism spectrum disorders are a class of developmental disorders that impair social skills, behavior, and communication (Center for Disease Control). ASDs are considered ‘spectrum’ disorders because each patient has a unique experience in the nature and severity of their symptoms (Center for Disease Control). Under the umbrella of ASDs, there are three types of disorders, including Autistic disorder, Asperger Syndrome, and Pervasive Developmental Disorder Not Otherwise Specified (Center for Disease Control). Autistic disorder is the most severe of the three, and patients exhibit significant problems with language, communication, and behavior (Center for Disease Control). Furthermore, people with Autistic disorder often have some intellectual impairment (Center for Disease Control). Asperger Syndrome is a milder form of autistic disorder where patients have some developmental delays, but their language and intellect are not affected (Center for Disease Control). The mildest of the ASDs is the pervasive developmental disorder. These patients usually don’t meet all of the criteria for autistic disorder, but do show some signs of social and communication problems (Center for Disease Control). The number of children diagnosed with ASD is growing, and currently 1 in 88 children fall somewhere on the spectrum (Mari-Bauset et al., 2013). Boys are four times more likely than girls to have autism, and while the exact cause of these disorders is unknown, both genetic and
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Young adults with autism spectrum disorders (ASD), have struggled to obtain employment after completing high school or college. In many studies of young adults with ASD, low rates of employment are reported (4.1 and 11%) despite their intellectual abilities. Moreover, research on interventions for adults with ASD is scarce, and only 4% of all studies of ASD in 2010 were longitudinal studies.
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