Definition and demographics of developmental disabilities
According to Public Law 106–402, the Developmental Disabilities Assistance and Bill of Rights Act of 2000, the term ‘‘developmental disability’’ means a severe, chronic disability of an individual that -
(i) is attributable to a mental or physical impairment or combination of mental and physical impairments;
(ii) is manifested before the individual attains age 22;
(iii) is likely to continue indefinitely;
(iv) results in substantial functional limitations in 3 or more of the following areas of major life activity:
(I) Self-care.
(II) Receptive and expressive language.
(III) Learning.
(IV) Mobility.
(V) Self-direction.
(VI) Capacity for independent living.
(VII) Economic self-sufficiency; and
(v) reflects the individual’s need for a combination and sequence of special, interdisciplinary, or generic services, individualized supports, or other forms of assistance that are of lifelong or extended duration and are individually planned and coordinated.
There are most likely approximately 43,000 individuals living with developmental disabilities in Connecticut, and these are comprised of individuals who live with intellectual disabilities, cerebral palsy, epilepsy, autism, deafness, blindness, psychiatric disabilities, substance use disorders, and physical disabilities.
In September 2019, the federal Administration on Community Living (ACL) summarized the more recent estimates of the prevalence of developmental disabilities. These estimates range from 0.79% to 1.58% or about 1.2% ±0.4%, which suggest that about 43,000 ±14,000 people are living with developmental disabilities in Connecticut. (Ref. 2)
Though developmental disability has been traditionally associated with intellectual disability, they are not the same thing. According to ACL, between 35% and 67% of people with developmental disability have intellectual disability, which suggests that about 0.8% of the people in Connecticut may live with developmental disability and intellectual disability. (Ref. 2,3)
Perhaps 35% of people diagnosed with intellectual disability have psychiatric disabilities so the prevalence of psychiatric disabilities with developmental disability is estimated to be about 0.7% of the general population. (Ref. 4, 6)
Approximately 34% of people diagnosed with intellectual disability have autism so the prevalence of autism with developmental disability is estimated to be about 0.7% of the general population. This estimate coincides with estimates of “severe” autism being about one third the autistic population. (Ref. 5, 6)
Substance use disorders may also satisfy the criteria for developmental disability. Perhaps 2% of the population is using illicit drugs other than marijuana or hashish. (Ref. 7, 8, 9)
About 1 in 323 children have been identified with cerebral palsy and 30.6% of those have limited or no walking ability. (Ref. 10)
The CDC reports approximately 36,000 cases of active epilepsy in Connecticut. (Ref. 13) Approximately 6% of persons with epilepsy are hospitalized each year. (Ref. 12)
About 0.3% of children in the United States are born with a detectable level of hearing loss in one or both ears and about 2% of adults aged 45 to 54 have disabling hearing loss. (Ref. 13)
Approximately 1% of the population is blind in childhood and at age 40. (Ref. 14, 15)
Approximately 0.4% of people are born with muscle, bone, brain, or spine defects and perhaps 4% of adults under the age of 45 have a disability in mobility. (Ref. 16, 17)
These are all inexact estimates because the references do not all use the same definitions and because there are significant comorbidities among these conditions that amount to double counting. Nevertheless, these estimates are useful guide to the levels of need for public services and supports in Connecticut.
Comorbidities among these conditions are significant and may be an indicator of developmental disability in so far as individuals with multiple disabilities may be likely to have substantial functional limitations in three or more major life activities.
References
1. Public Law 106–402, Developmental Disabilities Assistance and Bill of Rights Act of 2000. https://www.congress.gov/bill/106th-congress/senate-bill/1809
2. Havercamp, S.M., Krahn, G., Larson, S., Weeks, J.D., and the National Health Surveillance for IDD Workgroup (2019). Working Through the IDD Data Conundrum: Identifying people with Intellectual Disability and Developmental Disabilities in National population Surveys. Washington, D.C.: Administration on Intellectual and Developmental Disabilities. https://aclprdep01.azureedge.net/cdn/ff/1iflcHhToo9FRTlfo47Yw-wct5dWX-Sf_RHQqY0XJhI/1569854188/public/Aging%20and%20Disability%20in%20America/National_Data_Paper_AIDD-ACL_09.25.2019%20508%20compliant.pdf
3. Gollay, Elinor. Summary Report on the Implications of Modifying the Definition of a Developmental Disability. Gollay & Associates, Santa Fe, 1981.
4. Serving Individuals with Co-occurring Developmental Disabilities and Mental Illness: Systems Barriers and Strategies for Reform. National Association of State Mental Health Program Directors, Alexandria, VA, October 2004.
5. Elsabbagh, Mayada, et al. Global Prevalence of Autism and Other Pervasive Developmental Disorders. Autism Research 5:160-179, 2012.
6. Valerie Bradley, Dorothy Hiersteiner and Jessica Maloney, Human Services Research Institute; Laura Vegas and Mary Lou Bourne, National Association of State Directors of Developmental Disabilities Services. What Do NCI Data Reveal About People Who Are Dual Diagnosed with ID and Mental Illness? National Core Indicators™ DATA BRIEF, OCTOBER 2019.
7. McCrory, E.J. and L. Mayes. Understanding Addiction as a Developmental Disorder: An Argument for a Developmentally Informed Multilevel Approach. Current Addiction Reports. 2015; 2(4): 326-330.
8. Behavioral Health Trends in the United States. Substance Abuse and Mental Health Services Administration.
http://www.samhsa.gov/data/sites/default/files/NSDUH-FRR1-2014/NSDUH-FRR1-2014.htm#idtextanchor007
9. National Surveys on Drug Use and Health. Substance Abuse and Mental Health Services Administration. https://www.samhsa.gov/data/sites/default/files/reports/rpt23259/NSDUHsaeTotals2018/NSDUHsaeTotals2018.pdf
10. Data and Statistics for Cerebral Palsy. Centers for Disease Control and Prevention. https://www.cdc.gov/ncbddd/cp/data.html
11. Epilepsy Data and Statistics. Centers for Disease Control and Prevention. https://www.cdc.gov/epilepsy/data/index.html
12. Hospitalization for Epilepsy. Centers for Disease Control and Prevention. https://www.cdc.gov/mmwr/preview/mmwrhtml/00039474.htm
13. Quick Statistics About Hearing. National Institute on Deafness and Other Communication Disorders. https://www.nidcd.nih.gov/health/statistics/quick-statistics-hearing
14. Atowa, U. C. et al. Visual problems: a review of prevalence studies on visual impairment in school-age children. Int J Ophthalmol. 2019; 12(6): 1037–1043.
15. Blindness Tables. National Eye Institute. https://www.nei.nih.gov/learn-about-eye-health/resources-for-health-educators/eye-health-data-and-statistics/blindness-data-and-statistics/blindness-tables
16. Data & Statistics on Birth Defects. National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention. https://www.cdc.gov/ncbddd/birthdefects/data.html
17. Prevalence of Disability and Disability Type Among Adults. Centers for Disease Control and Prevention. https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6429a2.htm?s_cid=mm6429a2_w