What is a Developmental Disability


Developmental Disabilities

This is a term used to describe lifelong disabilities because of mental and/or physical or a combination of mental and physical impairments, manifested before age twenty-two. I use most commonly the term in the United States to refer to disabilities affecting daily functioning in three or more of the following areas.

  • capacity for independent living
  • economic self-sufficiency


  • mobility
  • receptive and expressive language
  • self-care
  • self-direction

Usually people with mental retardation, cerebral palsy autism spectrum disorder, various genetic and chromosomal disorders such as Down syndrome and Fragile X syndrome, and Fetal Alcohol Spectrum Disorder are described as having developmental disabilities.

This use of the term is synonymous with the use of the term learning disability in the United Kingdom and intellectual disability in Australia, Europe, Canada and elsewhere.

Cognitive disability is also used synonymously in some jurisdictions. Developmental disabilities are usually classified as severe, profound, moderate or mild, as assessed by the individual’s need for supports, which may be lifelong

Causes of developmental disabilities

There are many social, environmental and physical causes of developmental disabilities, although for some a definitive cause may never be determined. Common factors causing developmental disabilities include:

  • Brain injury or infection before, during or after birth
  • Growth or nutrition problems
  • Abnormalities of chromosomes and genes
  • Babies born long before the expected birth date – also called extreme prematurity
  • Poor diet and health care
  • Drug misuse during pregnancy, including excessive alcohol intake and smoking.
  • Child abuse can also have a severe effect on the development of a child, specifically the socio-emotional development.

Developmental disabilities affect between 1 and 2% of the population in most western countries, although many government sources acknowledge that statistics are flawed in this area.

The worldwide proportion of people with developmental disabilities is believed to be approximately 1.4%. It is twice as common in males as in females, and some researchers have found that the prevalence of mild developmental disabilities is likely to be higher in areas of poverty and deprivation, and among people of certain ethnicities.

This div height required for enabling the sticky sidebar