Genetic Diagnostics in Children and Adolescents with Mental DisordersAbstract: In Germany, genetic testing is part of the guideline-based diagnostic work-up for patients with intellectual disability. This is particularly the case for patients who show additional symptoms (i. e. malformations, epilepsy) or abnormal growth (i. e. microcephaly or macrocephaly). Implementation of diagnostic genetic testing is currently hampered by the still-limited practical experience of colleagues practicing child and adolescent psychiatry (CAP) and the little-practiced interaction with physicians working in clinical genetics. Additionally, the current funding modalities for genetic testing are not well-suited for routine clinical care in CAP. This paper presents a guide for physicians working in CAP who aim to implement guideline-based genetic testing into their routine clinical care. It focuses on steps relevant to ordering genetic testing, from obtaining informed consent to receiving and reporting the test results to those affected.