Table of Contents:
Autism-Spectrum-Disorders (ASD) are defined by deficits in social communication and interaction as well as repetitive, stereotyped behaviors. ASD are a group of complex, heterogeneous disorders associated with several comorbidities and many relevant differential diagnoses. Symptom presentations change over the lifespan and depend on several factors. This makes diagnosing ASD a major challenge for practitioners. Valid and reliable diagnostic instruments are essential for providing the best care and treatment possible. The present cumulus introduces four separate studies focusing on aspects of diagnostics and differential diagnostics of ASD. The first two studies examined the diagnostic utility of the Autism Diagnostic Observation Schedule (ADOS) for children, adolescents and adults with a special focus on relevant differential diagnoses and gender disparities. Results are in favor of good utility in clinical practice, with some fundamental restrictions regarding certain differential sub groups. Due to these results, a high degree of specialization on institutional and individual level is recommendable. The third study examined the diagnostic utility of the ADOS focusing on clinicians’ and case characteristics. Results indicate high variance in ADOS diagnostic results in clinical practice. In order to ensure sufficiently high levels of reliability, regular supervision and calibration of diagnostic decisions are advisable. The fourth study focused on the differentiation of ASD via assessment of facial emotion recognition (FER) performances, considering ADHD symptoms as possible influencing factors. Results indicate that children with ASD and comorbid ADHD, possibly mediated by reaction times, show weaker FER performances and that an increase of deficits is more relevant in older children. Diagnostics of ASD should therefore focus on comorbid ADHD symptoms in order to initiate individually tailored interventions.