Intellectual Disability Disorder

IDD (Intellectual Disability Disorder) is present when there is a below average intelligence or mental capacity. They may lack skills considered necessary for daily living and may learn these more slowly than others. There are generally two areas affected: intellectual functioning and adaptive behaviors. While most people score between 85 to 115, people who are intellectually disabled score less than 70 to 75 which affects 1% of the population.

Symptoms and Diagnosis

Causes of IDD can include problem during pregnancy or childbirth, illness such as meningitis, injuries such as head trauma, genetic conditions, and other causes which may remain mysterious. Signs of IDD can include late development of skills such as rolling over, sitting up, walking, talking, dressing, feeding, and toileting. Difficulties with behavior, problem solving, and learning action/consequence relationships may also be present. Those with Severe IDD may also suffer from seizures, mood disorders, sensory problems, and problems with movement. When diagnosing IDD three factors are taken into account including parent interviews, observations, and testing of both intelligence and adaptive behaviors. IDD is present when adaptive behavior and IQ deficiencies are both present. Diagnosis is important because it allows for making the determination of what kind and how much and what kind of support will be needed.


Treatment encompasses a multifaceted approach including help from special education providers, language therapists, behavioral therapists, and occupational therapists. This approach is aimed at helping those with IDD live their life to their fullest. Psychiatric providers can help by treating comorbid psychiatric illness such as mood disorders and behavioral disturbances.