What are Intellectual and Developmental Disabilities?
Intellectual and developmental disabilities is a state of functioning that begins in childhood and is characterized by limitation in both intelligence and adaptive skills. The term refers to substantial limitations in present functioning. It is characterized by significantly sub-average intellectual functioning, existing concurrently with related limitations. These related limitations must appear in two or more of the following adaptive skill areas:

• communication
• health and safety
• self-care
• community use
• home living
• self-direction
• functional academics
• leisure or work
• social skills

With appropriate support services over a sustained period, the life functioning of the person with intellectual and developmental disabilities will generally improve. (American Association on Intellectual and Developmental Disabilities, 2000)

Categorizations of Intellectual and Developmental Disabilities

There are two generally referenced categorizations of intellectual and developmental disabilities: intellectual level categorizations and adaptive behavior categorizations. (Texas Department of Mental Health and intellectual and developmental disabilities, Public Information Office, 2000)

Intellectual Level Categorizations of Intellectual and Developmental Disabilities

When categorizing persons with intellectual and developmental disabilities, an I.Q. (Intelligence Quotient) is commonly referenced when describing the intellectual level of functioning.

• Mild (IQ 55 to 70)
• Moderate (IQ 40 to 54)
• Severe (IQ 25 to 39), and
• Profound (IQ below 25)

Adaptive Behavior Categorizations of intellectual and developmental disabilities

Adaptive behavior is based on supports needed by the individual. (Texas Department of Mental Health and intellectual and developmental disabilities, Public Information Office, 2000). The "level of support" required to assist a person with intellectual and developmental disabilities is identified by the following terms:

• Intermittent
• Limited
• Extensive
• Pervasive
• Pervasive Plus