Intellectual and Developmental Disabilities (IDDs)

IDDs are disorders that are usually present at birth and that uniquely affect the trajectory of the individual’s physical, intellectual, and/or emotional development.

The signs of IDDs vary depending on the condition. A few signs include a delay in motor skills, difficulty remembering things, and challenges solving problems.

The exact number of people affected by IDDs is unknown. This is because IDDs cover a wide range of conditions, many of which are diagnosed several years after birth, rather than in newborns.

IDDs have a variety of causes. Some possible causes include genetic mutations, chromosome abnormalities, infection during pregnancy, preterm birth, and traumatic brain injury.

A test of intelligence or cognition is typically used to diagnose an intellectual disability. Clinicians will also observe a child’s behavior for signs of a disability and assess adaptive behavior.

Many IDDs have no cure, but there are often ways to treat their symptoms. Your healthcare provider can help you and your child navigate treatment options for IDDs.

First, speak with your child’s healthcare provider if you suspect your child has an IDD. If the healthcare provider notices signs, then see a developmental pediatrician or another specialist.

NICHD conducts and supports research on IDDs and on many disorders associated with IDDs.

NICHD conducts and supports a variety of clinical research projects related to IDDs.

Links to websites of groups that study or provide information about IDDs.