Intellectual developmental disorder (Intellectual disability) is a disorder which begins during the developmental period. Deficits within the developmental years must be present regardless of whether or not individuals were diagnosed in childhood, adolescence, or adulthood. This disorder impacts intellectual functioning and adaptive functioning. Deficits in intellectual functioning may appear as low academic performance, difficulty learning and retaining previously learned concepts, communication, or acting out physically on their environment. Deficits in adaptive functioning may appear as difficulty completing personal independence skills (i.e., brushing teeth, chores), difficulty completing everyday skills, deficits in social functioning, difficulty being independent, and difficulty adapting to new environments¹⁵.

The severity of intellectual developmental disorder is characterized by four levels; mild, moderate, severe, and profound. Though severe forms of the disorder may be observable from an individual's earliest days, individuals with more mild versions of the disorder may not display symptoms until middle school or higher. While individuals with mild forms of the disorder may be able to live independently with appropriate supports, for those with more severe forms of the disorder, lifetime support may be required.
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Intellectual functioning is usually measured with individually administered, valid, and culturally appropriate tests of intelligence. If you feel your child may display symptoms consistent with an intellectual developmental disorder, please consult your local school or school representative to explore potential options for testing and other academic resources and services.​

Symptoms⁹:

• Deficits in reasoning, problem-solving, planning, abstract thinking, judgment, and academic learning. 
• Deficits in interpersonal communication, ability to relate to peers as friends, problem-solving, and adjusting to new environments.
• Low academic achievement. 
• Difficulty remembering previously learned lessons or information.
• A tendency to be gullible within relationships which may result in being taken advantage of. 
• When frustrated, becoming physically aggressive with people or objects in their immediate environment.​

Watch: Intellectual Disability