Correlates of Psychomotor Symptoms In Autism
Stereotypical behaviors are defined as repetitive motor or vocal responses that serve no obvious adaptive function. The current diagnostic classification system, the DSM-IV-TR, includes the presence of stereotypical behaviors of interest in its criteria for autism. Rescarch suggests that as many as 85% of children with autism exhibit relative behaviors or mannerisms. However, stereotypical behaviors are not specific to autism and are associated with other disorders such as Tourette's syndrome, schlzophrenia, and mental retardation. Although the DSM-IV-TR criteria for stereotypical behaviors, as outlined in the diagnostic criteria for autistic disorder, focuses on motor symptoms that tend to occur in excess (e.g., twirling, spinning, head-banging), a broader conceptualization of the types of motor abnormalities observed in individuals with autism has been proposed more recently. Stereotyped patterns of behavior include not only excessive atypical movement but also the loss of typical movement (e.g., catatonia) in this broader definition. support for this definition is evidenced by both clinical observations and empirical research. Research examining the overlap between catatonia and other stereotypic behaviors among individuals with autism suggest that the greatest risk for catatonic behaviors occurs in adolescence and may be precipitated by stressful events. Assessment tools for autism often include some measure of stereotyped behaviors and interest, but the presence of stereotypy is not in and of itself a pathiognomonic sign of autism. Focusing primarily on the presence of classic stereotypical behaviors in diagnoses may subsequently lead to overidentifying autism in very young or mentally retarded individuals. A number of theories have been proposed over the years to explain the function and etiology of stereotypical behaviors. Lovaas and his colleagues, for example, proposed that the sensory and perceptual stimuli created through repetitive behaviors may be self stimulating. Others suggest that stereotypical behaviors are maintained by socially mediated positive and negative reinforcers; whereas biological theories focus on dysfunctions in the serotonin, opioid, and dopaminergic systems in the brain.
GABA is Autism and Related Disorders
Jordan, S. S.,
(2005). Correlates of Psychomotor Symptoms In Autism. GABA is Autism and Related Disorders, 71, 343-357.
Available at: http://aquila.usm.edu/fac_pubs/2905