What are Developmental Disabilities?

Intellectual and Developmental Disabilities (IDDs)

IDDs are differences that are usually present at birth and that uniquely affect the trajectory of the individual’s physical, intellectual, and/or emotional development.

Intellectual disability is a term used when there are limits to a person’s ability to learn at an expected level and function in daily life and for some the cause is not known, according to the Centers for Disease Control and Prevention (CDC).

Many common intellectual disabilities happen before birth such as Down syndrome, fetal alcohol syndrome, fragile X syndrome, genetic conditions, birth defects, and infections while other disabilities can occur from a serious head injury, stroke, or certain infections.

Intellectual disabilities can start any time before a child turns 18, according to the National Institute of Health. They are characterized with differences with function and behavior:

  • Intellectual functioning or intelligence, which include the ability to learn, reason, problem solve, and other skills; and
  • Adaptive behavior, which includes everyday social and life skills.

Developmental disabilities tend to be a broader category of challenges throughout a person’s life that can encompass intellectual differences, physical differences, or a combination of the two.

Developmental disabilities are defined by the CDC as impairments in physical, learning, language or behavior areas, and include:

  • Autism spectrum disorders
  • Cerebral palsy
  • Attention-deficit/hyperactivity disorder
  • Learning or intellectual disabilities
  • Hearing loss
  • Vision impairment
  • Other developmental delays

"IDD" is the term often used to describe situations in which intellectual disability and other disabilities are present. Many of these conditions affect multiple body parts or systems.

Cerebral palsy, Down syndromeFragile X syndrome, and autism spectrum disorders (ASDs) are examples of IDDs related to problems with the nervous system as these disorders affect how the brain, spinal cord, and nervous system function, which can affect intelligence and learning. These conditions can also cause other issues, such as behavioral disorders, speech or language difficulties, seizures, and movement issues.

Some conditions can also impact how the body’s senses work due to their affect on the way the brain processes information from sight, hearing, touch, taste or smell, known as sensory processing disorder. For example, individuals with ASDs can become overwhelmed in loud environments or have difficulties with the texture of a fabric on their skin.

CDC’s National Center on Birth Defects and Developmental Disabilities has additional information on certain disabilities, developmental disorders, and related conditions. Click on the following to learn more:

New Jersey’s Division of Developmental Disabilities (DDD) serves individuals who are over the age of 21 that meet eligibility requirements. Even though DDD services cannot start until age 21, individuals can be evaluated for eligibility as early as age 18.

Individuals receiving services through school can continue doing so through age 21. If they choose to graduate or leave school between the ages of 18 and 21, it is critical to discuss service options with their school’s Individualized Education Program (IEP) Team and transition coordinator.

Individuals 18-21 years of age who have met eligibility requirements can receive services through the NJ Children's System of Care, within the Department of Children and Families (DCF).

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