What are the signs of intellectual and development disabilities (IDDs)?

The signs of IDDs vary for particular conditions.

IDDs that are more severe may show up sooner. Some of the signs of IDD may include1,2:

  • Sitting up, crawling, or walking later than other children of similar age
  • Learning to talk later or having difficulty speaking
  • Finding it hard to remember things
  • Having trouble understanding the rules of social behavior
  • Having difficulty "seeing" or understanding the outcomes of actions
  • Having trouble solving problems

Developmental milestones can be monitored to identify delays (e.g., in walking or talking) that could indicate an IDD.

To learn more about developmental milestones, and milestones for different ages, visit the following websites:


  1. Centers for Disease Control and Prevention. (n.d.). Intellectual disability fact sheet. Retrieved August 9, 2012, from https://www.cdc.gov/ncbddd/developmentaldisabilities/facts-about-intellectual-disability.html
  2. National Dissemination Center for Children with Disabilities. (2011). NICHCY disability fact sheet #8: intellectual disabilities. Retrieved August 9, 2012, from https://www.parentcenterhub.org/disability-landing/ external link
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