Intellectual Disability: Definition, Impact on Daily Life, and Support Strategies
Intellectual disability (ID) is a neurodevelopmental disorder characterized by deficits in intellectual functioning (IQ ≈ <70) and adaptive functioning (conceptual, social, practical skills), onset <18 years.
Severity Levels (DSM-5 / AAIDD)
| Severity | IQ Range | Adaptive Functioning | Typical Support Needs |
|---|
| Mild | 50–69 | Some difficulty with complex tasks; can live independently with support | Intermittent (as needed) |
| Moderate | 35–49 | Basic self-care, communication; needs daily support | Limited (regular) |
| Severe | 20–34 | Limited communication; extensive support for all activities | Extensive (daily, structured) |
| Profound | <20 | Minimal symbolic communication; total care | Pervasive (constant, nursing-level) |
Impact on Daily Life Domains
- Learning/Education: Individualized Education Program (IEP), specialized instruction, assistive tech.
- Communication: Speech therapy, AAC (devices, sign, PECS).
- Social: Social skills training, supported friendship, community inclusion.
- Self-Care: Task analysis, chaining, adaptive equipment.
- Employment: Supported employment, job coaching, customized jobs.
- Independent Living: Supported living, shared housing, smart-home tech.
- Health: Higher rates of epilepsy, mental illness, sensory impairments, dental disease — need coordinated care.
Etiology (Many Cases Multifactorial)
- Genetic (Down, Fragile X, Rett, Prader-Willi, chromosomal).
- Prenatal (infections, teratogens, malnutrition).
- Perinatal (hypoxia, prematurity, kernicterus).
- Postnatal (trauma, infection, lead, malnutrition).
- Unknown (~30–50%).
Rights and Philosophy
- UN CRPD: Full inclusion, accessibility, supported decision-making.
- People-first language: "person with intellectual disability."
- Presume competence; focus on strengths.
With appropriate supports, people with ID lead meaningful, contributing lives. Early intervention and lifelong opportunity are key.
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