Diagnostik bei Autismus-Spektrum-Störungen

The autism spectrum disorder is a neurodevelopmental disorder with a worldwide prevalence of 1 %. It is characterized by impairments in social communication and the presence of restricted, repetitive or stereotypic behaviors and interests. A high amount of symptom overlaps as well as high rates of comorbidities lead to a challenging diagnostic process. Thus, there is an essential need to study the diagnostic accuracy of autism-specific instruments to improve the diagnostic process leading to accurate diagnoses. The present cumulus introduces two studies focusing on aspects of diagnostics and differential diagnostic of autism spectrum disorder. The first study explored the latent structure of autism spectrum disorder by the performance of several analyses. Results indicate that a categorical classification is not able to adequately represent autism as heterogenous disorder. A hybrid model of autism spectrum disorder taking both categories and dimensions into account seems to be more appropriate than a dimensional model, which defines autism as a spectrum. Results show evidence for three classes of autism with quantitative and qualitative differences in the severity of symptoms. This latent structure seems suitable for early detection of cases with autism spectrum disorder in differentiation to other mental disorders. The second study examined the differentiation of autism spectrum disorder and mood as well as anxiety disorder. As these disorders are relevant differential diagnoses, data of the autism diagnostic observation schedule and caregiver interviews of children, adolescents and adults were analysed. The study aimed to identify behavioral items that are able to differentiate between autism and mood or anxiety disorders. Results indicate a combination of social-communicative items to be suitable for classification between both disorders. High rates of symptom overlap increase the risk of misinterpretation of present symptoms. Therefore, all available information should be taken into account for the diagnosis so that an adequate form of treatment is selected taking affective and anxious symptoms into account. In summary, the studies based on behavioral observation data provide important new information in addition to studies based on external judgments. Further investigations on diagnostic process of autism spectrum disorder are necessary in order to develop diagnostic instruments that are sensitive to the heterogeneity of autism and to initiate adequate treatments. Improving the understanding is essential für initiating suitable forms of treatment.