Mental retardation epidemiology and demographics

The prevalence of intellectual disability has remained stable over the years. It is noted that it occurs more in males and there is no racial predilection when it comes to the prevalence of this condition.

The prevalence is 1% in the general population, with 6 per 1000 persons having a severe mental disability. During 2014–2016, the prevalence of children ever diagnosed with any developmental disability significantly increased, from 5.76% in 2014 to 6.99% in 2016 while the prevalence of children ever diagnosed with intellectual disability did not significantly change from 2014 to 2016. ^[1]

The prevalence of intellectual disability was lower among younger children than older children: 0.73% among children aged 3–7 years, 1.45% among children aged 8–12 years, and 1.40% among children aged 13–17 years. ^[2]

The prevalence of children diagnosed with intellectual disability did not differ significantly by race and Hispanic ethnicity. The difference in the prevalence of intellectual disability between non-Hispanic black children (1.53%) and non-Hispanic other children (0.86%) was not statistically significant (p = 0.21). ^[3]

Males are more likely to have a mental disability with a ratio of 2:1. During 2014–2016, the prevalence of children ever diagnosed with intellectual disability was 1.48% among boys and 0.90% among girls. ^{[4] [5] [6]}

In the United States, individuals with a severe intellectual disability are at 0.3-0.5% and 9.21 per 1000 people in developed countries. ^{[7] [5]}

Prevalence is at 16.41 per 1000 people in developing countries. ^{[8] [5]}