MENTAL RETARDATION

DR SEDDIGH

Pre test Custodial MR ???? Severe MR ???? % Sex >>>>>> ???? Peer bahavior ???? Intellectual disability ????

HISTORY Mental retardation recognized perhaps

longer than any other currently studied in psychology

Written documents from ancient Egypt made oblique reference to the condition as early as about 1500 BC was often viewed as part of mental illness

relatively common

Historical Treatment of MR Egypt 1500 B.C. Ancient Greece 200 A.D. Rome Middle Ages Reformation

Features of Mental RetardationDSM-IV Criteria

significantly subaverage IQ (<70) concurrent deficits or impairments in

adaptive functioning characteristics evident prior to age 18

Mental Retardation defined in the Diagnostic and Statistical

Manual of Mental Disorders-IV as: significantly subaverage intellectual functioning:

an IQ of approximately 70 or below concurrent deficits or impairments in present

adaptive functioning in at least two of the following areas:communication, self-care, home living, social/interpersonal skills, use of community resources, self-direction, functional academic skills, work, leisure, health, and safety; and

onset before age 18 years.   

Describing and Classifying Mental Retardation

5 DSM-IV-TR severity classifications for mental retardation

Mild – IQ of 50-55 to about 70 (Educable) Moderate – IQ of 35-40 to 50-55 (Trainable) Severe – IQ of 20-25 to 35-40 (Custodial) Profound – IQ below 20 or 25 (Custodial) Unspecified – presumption of mental

retardation but intelligence not testable with standardized instruments

Mild Retardation Some 85% of all people with mental retardation

fall into the category of mild retardation (IQ 50–70) They are sometimes called “educably retarded”

because they can benefit from schooling typically not identified until elementary school years

People with mild retardation typically need assistance but can work in unskilled or semiskilled jobs Intellectual performance seems to improve with age

Mild Retardation Research has linked mild mental

retardation mainly to sociocultural and psychological causes, particularly: Poor and unstimulating environments Inadequate parent-child interactions Insufficient early learning experiences

Mild Retardation Although these factors seem to be the

leading causes of mild mental retardation, at least some biological factors may also be operating Studies have linked mothers’ moderate

drinking, drug use, or malnutrition during pregnancy to cases of mild retardation

Moderate, Severe, and Profound Retardation Approximately 10% of persons with mental

retardation function at a level of moderate retardation (IQ 35–49) They can care for themselves and benefit from

vocational training About 4% of persons with mental retardation

display severe retardation (IQ 20–34) They usually require careful supervision and

can perform only basic work tasks

Moderate, Severe, and Profound Retardation About 1% of persons with mental retardation

fall into the category of profound retardation (IQ below 20) With training they may learn or improve basic

skills but they need a very structured environment

Severe and profound levels of mental retardation often appear as part of larger syndromes that include severe physical handicaps

Prevalence 1-3% of population (depending on cutoff)

Slightly more males than females

More prevalent in lower SES and in minority groups, especially for mild MR; no differences for more severe levels

Developmental Course Often children with mental retardation experience

helplessness and frustration in their learning environments, which leads to low expectations and limited success

With appropriate training and opportunities, children who have mild mental retardation may develop good adaptive skills in other domains

Language and Social Development Expressive language development may be weak in children with

Down syndrome

Fewer signals of distress or desire for proximity with primary caregiver, which can influence attachment

Self-recognition often delayed, but positive

Problems in the development of self-other understanding

Deficits in social skills and social-cognitive ability; can lead to rejection by peers

Emotional and Behavioral Problems

Emotional and behavioral disturbances four times greater than the general population

Impulse control problems, anxiety problems, and mood problems common

ADHD-related symptoms also common

Pica and self-injurious behavior also common among those with severe and profound MR

Other Disabilities Associated with MR Can be associated with other pervasive

physical and developmental disabilities, including sensory impairments, cerebral palsy, and epilepsy

Chance of other disability increases as degree of intellectual impairment increases

Other Disabilities Associated with MR (cont.)

Etiology The causes of mental retardation are many

and varied

In some cases, pathology of a physiological or biological nature can be identified

for as many as 30–40% of those with mental retardation, causation is unknown

Causes of MR•Genetic Causes (65%) Chromosomal defects;

Structural anomalies;Inborn errors of metabolism  

• Intrauterine Risk Factors (15%) Asphyxia; Developmental defects; Malnutrition/ Intrauterine growth retardation Maternal infections or diseases; Maternal substance abuse 

•Perinatal Risk Factors (10%):Anoxia; Birth trauma;Low birth weight;Prematurity

•Neonatal and Postnatal Causes (10%):Childhood infections and diseases; Environmental toxins; Severe malnutrition, Trauma 

Causes of Mental Retardation Many organic causes have been discovered but majority of cases

cannot be explained, especially for mild mental retardation

The two-group approach: organic mental retardation- includes chromosome

abnormalities, single gene conditions, and neurobiological influences

cultural-familial mental retardation- includes family history of mental retardation, economic deprivation, inadequate child care, poor nutrition, and parental psychopathology

Causes of Mental Retardation (cont.)Inheritance and the Role of the Environment

heritability of intelligence is approximately 50%

prenatal influences may be mistaken for genetic when they are actually environmental

Causes of Mental Retardation (cont.)

Genetic and Constitutional Factors chromosomal abnormalities are the most common cause of

severe MR Down syndrome due to an additional 21st chromosome Fragile-X syndrome, the most common cause of inherited MR,

is associated with the FMR-1 gene Prader-Willi and Angelman syndromes both associated with

abnormality of chromosome 15; believed to be spontaneous genetic birth defects occurring around the time of conception

inborn errors of metabolism (referred to as single-gene conditions) can result in syndromes such as PKU

Causes of Mental Retardation

Causes of Mental Retardation (cont.)Neurobiological influences

adverse biological conditions (e.g., malnutrition, exposure to toxins, Rubella, prenatal and perinatal stressors)

infections, traumas, and accidental poisonings during infancy and childhood

prenatal alcohol exposure can lead to a Fetal Alcohol Spectrum Disorder (FASD)

Social and Psychological influences deprivation of physical and emotional care and social

stimulation particularly influential

Genetic Factors Down syndrome

three types of Down syndrome, each resulting from a different type of chromosomal error. Nondisjunction

Translocation

Mosaicism

Mental Retardation: Trisomy 21

Distinctive facial features Mild MR Parental age Medical complications

Mental Retardation: Fragile X Physical characteristics

Females vs. Males Autism

Genetic Factors phenylketonuria (PKU), an inherited metabolic

disorder that occurs in about 1 of every 10,000 live births Affected infants lack the ability to process

phenylalanine, severely damages the central nervous system

Mental Retardation: PKU (genetic)

Phenylalanine metabolizing deficiency

MR Restricted diet

Genetic Factors Maple syrup urine disease

Affected infants tend to excrete urine that has a distinctive odor of maple syrup

may cause severe intellectual impairment, although more often than not the condition is fatal

cause of this condition has been linked to metabolic deficiencies of three separate amino acids causing extreme CNS damage in the newborn

Untreated maple syrup urine disease is fatal; few untreated infants survive more than a few weeks

Genetic Factors Galactosemia involves difficulty in

carbohydrate (sugar) metabolism, rather than amino acid metabolism

Infants with galactosemia are unable to properly process certain sugar components in milk

Results are toxic damage to the infant’s liver, brain, and other tissues

Prevention, Education, Treatment Child’s overall adjustment is a function of parental

participation, family resources, social supports, level of intellectual deficit, temperament, and other specific deficits

Treatment involves a multi-component, integrated strategy that considers children’s needs within the context of their individual development, family and institutional setting, and community

Prenatal education and screening may prevent some cases of MR

Treatment of children with mental retardation

Three types of prenatal intervention Chromosomal analysis for Down

Syndrome or other genetic abnormalities may result decision to abort fetus

Treatment for Rh blood incompatibility between mother and fetus may prevent fetal damage.

Prenatal identification of a PKU problem may result in maternal dietary restrictions

Prevention, Education, Treatment (cont.)

Risk and protective factors affecting the psychological adjustment of intellectually disabled children

Prevention, Education, Treatment (cont.)Psychosocial treatments

intensive, child-focused, early intervention efforts are very promising (particularly for disadvantaged children)

optimal timing for intervention is in the preschool years behavioral techniques include shaping, modeling, graduated

guidance, and social skills training cognitive-behavioral techniques, such as self-instructional

training and metacognitive training family oriented interventions help families cope with the

demands of raising a child with MR

Postnatal Interventions Infant stimulation programs provide positive

developmental environment for very young children who are at risk because of prenatal or later environmental circumstances

Specific instruction for young children in language skills appears promising and probably should be implemented as early as possible

Inclusion of young children of school age in classrooms with non disabled peers

Continuous name shift “Mental Retardation” and “Learning

Disabilities” are outdated and unacceptable for users

“Intellectual Disabilities” adopted by IASSID / AAMR US President´s Commission DSM-IVTR 2005

Post test Custodial MR ???? Severe MR ???? % Sex >>>>>> ???? Peer bahavior ???? Intellectual disability ????

DR SEDDIGH

WITH

THANKS