Down Syndrome

Down syndrome (DS) is the most common chromosomal condition in the United States (US) and is the most common chromosomal cause of intellectual disability. It affects 1 out of 700 live births, and approximately 6000 babies are born with DS annually in the USA (de Graaf et al. Genet Med 19(4):439–47, 2017). Multiple medical comorbidities are more common in people with DS— for example, congenital heart defects and endocrine and gastrointestinal disorders. There is limited information on the exact prevalence of psychiatric disorders in people with DS. Overall, people with DS are at a higher risk of psychiatric disorders than the general population (McCarthy and Boyd. J Intellect Disabil Res 45(Pt 2):99–105, 2001). This chapter will provide a general overview of DS and review signs and symptoms of common psychiatric comorbidities. It will also provide a clinical approach to the assessment of medical and psychiatric comorbidities, as well as an overview of psychosocial and biological treatments. Finally, it will describe common medical conditions clinicians should be aware of that may affect psychiatric diagnosis and treatment planning.