ABSTRACT
Sibling research has expanded significantly since the first exploratory studies during the 1950s–1960s. Overall, researchers have determined that most siblings are doing well, with little to no risk for significant psychological or mental health issues. However, certain siblings may be at risk for sub-threshold levels of individual symptoms; in particular, several studies have shown increased rates of anxiety in siblings of individuals with intellectual and development disability (IDD) as compared to normative groups. This chapter summarizes results from existing sibling research, including individual, demographic, and family factors, as well as specific outcomes for the siblings of individuals with IDD. Although some researchers have focused on siblings of individuals with IDD as a group that is siblings of individuals with any type of IDD, other researchers have addressed siblings of individuals with a particular diagnosis, such as autism spectrum disorder (ASD) or Down syndrome (DS).
