Psychiatric Causes of Intellectual Disabilities Autism Spectrum
Disorder (ASD) A leading cause of intellectual disabilities (ID,
formerly mental retardation) is autism spectrum disorder (ASD).
A person may be diagnosed with both ASD and an ID. ASD has two
primary symptoms. First, people with ASD have trouble with
communication and social interaction. Second, they demonstrate
repetitive patterns of behaviors, interests, or activities. Some
examples are repetitive speech, ritualized patterns of behavior,
or fixation upon certain objects. Approximately 40% of people
with ID will also have ASD. However, nearly 70% of people with
ASD also have ID (reported in La Malfa, G., Lassi, S., Bertelli,
M., & Placidi, G.F., (2004). See also http://www.cdc.gov). Thus,
while ASD and ID share some similarities, they are not the same.
Although similar, the two disorders are often difficult to tease
apart. People with ASD might appear to meet the criteria for ID
because their IQ scores are low. However, these low test scores
may