(iii) Mental Retardation (Now termed "Intellectual Disability")
____________________________________________________________________________
Definition:
“Mental retardation,” now more accurately termed intellectual disability (ID) according to the DSM-5 and WHO ICD-11, refers to significantly below-average intellectual functioning and adaptive behavior that originates during the developmental period (before age 18).
American Association on Intellectual and Developmental Disabilities (AAIDD, 2010):
“Intellectual disability is characterized by significant limitations in both intellectual functioning (reasoning, learning, problem-solving) and in adaptive behavior, which covers a range of everyday social and practical skills.”
"Significant limitations in both intellectual functioning and in adaptive behavior, which covers many everyday social and practical skills. This disability originates before the age of 18."
(AAIDD, 2010; APA, 2013)
____________________________________________________________________________
1. Core Characteristics of Intellectual Disability
a. Intellectual Functioning Deficits
- IQ score typically below 70–75.
- Difficulty with reasoning, problem-solving, planning, abstract thinking, judgment, and learning from experience.
Schalock et al., (2010) emphasizes that intellectual functioning alone is not sufficient to diagnose ID—adaptive behavior must also be considered.
____________________________________________________________________________
b. Deficits in Adaptive Behavior
- Conceptual skills (e.g., language, literacy, money, self-direction)
- Social skills (e.g., interpersonal skills, social responsibility, self-esteem)
- Practical skills (e.g., personal care, occupational skills, travel/transportation)
Sparrow, Cicchetti & Balla, (2005) authors of the Vineland Adaptive Behavior Scales, widely used to assess adaptive behavior.
____________________________________________________________________________
c. Onset during the Developmental Period
Symptoms must appear before the age of 18 to distinguish ID from adult-onset conditions like dementia.
____________________________________________________________________________
2. Causes of Intellectual Disability
a. Genetic Conditions
Down syndrome, Fragile X syndrome, and Phenylketonuria (PKU) are common causes.
Roizen & Patterson, (2003) discuss the genetic and chromosomal basis of developmental delays in children.
b. Prenatal Factors
- Maternal infections (e.g., rubella, cytomegalovirus)
- Substance use (alcohol, drugs)
- Malnutrition or exposure to toxins (e.g., lead)
c. Perinatal and Postnatal Causes
- Complications during birth (e.g., oxygen deprivation)
- Traumatic brain injury
- Infections like meningitis or encephalitis
____________________________________________________________________________
3. Levels of Intellectual Disability
- Level Mild
- IQ Range 50–69
- Description Can achieve academic skills up to ~6th grade. May live independently with support.
- Level Moderate
- IQ Range 35–49
- Description Limited academic progress. May require supervised living.
- Level Severe
- IQ Range 20–34
- Description Little or no communicative speech. Needs constant supervision.
- Level Profound
- IQ Range Below 20
- Description Extensive support in all life areas. Often co-occurring physical disabilities.
APA, DSM-5, (2013) provides this classification for diagnostic purposes.
____________________________________________________________________________
4. Diagnosis and Assessment Tools
- Wechsler Intelligence Scale for Children (WISC-V)
- Stanford-Binet Intelligence Scales
- Vineland Adaptive Behavior Scales
- Bayley Scales of Infant and Toddler Development
____________________________________________________________________________
5. Educational and Social Implications
Children with intellectual disabilities often:
- Face difficulties in academic achievement
- May struggle with communication and social relationships
- Are at higher risk of being excluded or bullied
- Benefit from Individualized Education Plans (IEPs) and inclusive education strategies
UNESCO (2009) promotes inclusive education for children with disabilities to ensure equity and participation.
____________________________________________________________________________
6. Support Strategies
- Special education tailored to cognitive level
- Speech and occupational therapy
- Behavioral interventions
- Life skills training
- Parental and caregiver support
World Health Organization (WHO, 2022) advocates for community-based rehabilitation and family-centered approaches for better outcomes.
____________________________________________________________________________
7. Stigma and Societal Challenges
- Children with ID often face social stigma, marginalization, and lack of access to services—especially in low-income settings.
- Advocacy and public awareness are key to improving quality of life.
UNICEF (2013) notes that over 90% of children with disabilities in developing countries do not attend school.
____________________________________________________________________________
8. Legal and Policy Frameworks
- Individuals with Disabilities Education Act (IDEA, USA)
- UN Convention on the Rights of Persons with Disabilities (UNCRPD)
- The Rights of Persons with Disabilities Act (India, 2016)
____________________________________________________________________________
Conclusion
Intellectual disability is a developmental condition marked by significant limitations in intellectual functioning and adaptive behavior. It affects individuals in diverse ways and necessitates a combination of medical, educational, and psychosocial support systems. Shifting from the outdated term “mental retardation” to “intellectual disability” reflects a more humane, respectful, and inclusive approach in both academic and clinical settings.
____________________________________________________________________________
References:
- American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders (5th ed.).
- Schalock, R. L., et al. (2010). Intellectual Disability: Definition, Classification, and Systems of Supports. AAIDD.
- Sparrow, S. S., Cicchetti, D. V., & Balla, D. A. (2005). Vineland Adaptive Behavior Scales (2nd ed.). Pearson Assessments.
- Roizen, N. J., & Patterson, D. (2003). Down's syndrome. The Lancet, 361(9365), 1281-1289.
- World Health Organization. (2022). World Report on Disability.
- UNESCO. (2009). Inclusive Education: The Way of the Future.
- UNICEF. (2013). Children and Young People with Disabilities Fact Sheet.
