MENTAL RETARDATION
People with mental retardation were once teased and tormented.
Considered amusing, they were impersonated by court jesters and comic
entertainers.
People laughed at them.
Some terms applied to them were:
Idiots
Morons
Mental Defectives
FeebleFeeble-minded
Fools
Evolutionary Degenerates
Some religious authorities even considered them “changelings,”
changelings,” possessed by the
Devil.
The mildly retarded were kept at home. The more severely affected
affected were
institutionalized, often in dreadful conditions.
Today they receive better care and respect, but some stigma remains.
remains.
Definitions of Mental Retardation
Mental retardation has become recognized as a disorder because:
1. MR
affects functioning in many aspects of everyday life
with MR may appear physically different
3. MR is a chronic condition, often apparent from early in life
4. MR is worldworld-wide; many families have a member with MR
2. Children
Percentages of children in public schools diagnosed with learning disabilities or mental
retardation, 1977 – 1995.
—From Baumeister & Baumeister, 2000.
DSMDSM-IV Definition of Mental Retardation
DSMDSM-IV definition relies prominently, but not exclusively, on tested IQ
1. Mild MR, 5050-55 to upper limit of approximately 70 IQ
2. Moderate MR, 3535-40 to 5050-55 IQ
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3. Severe
MR, 2020-25 (limit of testability) to 3535-40
estimated IQ below 2020-25
5. MR, Severity Unspecified, usually because the person is at too low
low a level to test, not
cooperative, or too young
4. Profound,
Recognizing the limitations of relying on IQ alone, the DSMDSM-IVIV-TR now includes a
definition nearly identical to the following definition by the AAMR.
AAMR.
(American Association for Mental Retardation)
MR must be present before age 18 years in all definitions.
The AAMR Definition of Mental Retardation
In addition to IQ, the AAMR definition considers many aspects of functioning, called
adaptive behavior.
behavior.
The person must show significantly subsub-average IQ (below about 70 IQ).
Must also have limitations in a least 2 or more adaptive skills areas:
Communication
SelfSelf-Care
Home Living
Social Skills
Community Use
SelfSelf-Direction
Health and Safety
Functional Academics
Leisure
Work
In addition to the formal diagnostic criteria, children with MR don’
don’t expect to succeed, set low
personal goals, and quit early rather than struggle with tasks.
Teachers often expect little from them and don’
don’t urge them to try in reading, writing, and
problem solving.
Prevalence
Between 1% and 3% of the population meet the criteria for Mental Retardation
Slightly more males than females with MR
Mild MR identified more in low SES and some minority groups, especially
especially the
impoverished. No such differences with severe or profound MR
Course
Outlook is good for many with mild MR or CulturalCultural-familial Retardation. In nonnon-academic
settings they can function acceptably and are not considered retarded.
retarded.
Appropriate training and opportunities must be provided
Severe and profound MR, Organic Retardation,
Retardation, is lifelong, and biologically based.
2
Many people with MR are living longer; Down Syndrome patients live
live up to the midmid-50s on
average.
Issue of their care in later years, when some decline cognitively
cognitively due to gene damage in
those with Down Syndrome
Causes
Mild MR is more influenced by cultural and family environment
More severe MR is more likely to stem from genetic and other organic
organic factors
Overwhelming evidence that both genetic and nongenetic factors powerfully affect
intelligence. Heritability of intelligence is around 50% (proportion
(proportion of the variation of a trait in
a population that is attributable to genetic influences). So intelligence
intelligence is about 50% due to
environmental factors
Factors Associated with Mental Retardation
Factors Associated with Mental Retardation (cont’
(cont’d)
Prenatal Development
The developing fetus is naturally protected against many harmful agents, with
some exceptions:
Alcohol.
Alcohol. Fetal Alcohol Syndrome or milder fetal alcohol symptoms. Effects
Effects
range from very subtle to obvious physical defects and mental retardation.
retardation. Not
known how much alcohol is too much for pregnant women
Some illicit drugs can directly and indirectly affect the fetus. Fetal addiction,
nutritional insufficiency.
Rubella, syphilis, herpes.
Untreated maternal high blood pressure or diabetes
Infancy
and
Childhood
Perinatal factors include hypoxia, intracranial hemorrhage
Injuries such as: Shaken Baby Syndrome can lead to brain injury and MR
Common sequence of events in Shaken Baby Syndrome
An angry caretaker shakes a baby who won’
won’t stop crying
Weak neck muscles cause whiplash, bruising of the brain, and causing
causing bleeding around
the brain and behind the eyes
Results in apparent deep sleep. Seizures, blindness, paralysis, MR, sometimes death
Prevention
Adequate prenatal care for all mothers prevents many conditions that result in
MR
Informing parents of the genetic basis for some types of MR
Effective prevention and treatment programs for maternal substance
substance use and
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addiction
Public health ads to prevent pregnant women from smoking, drinking,
drinking, doing unhealthy diets
and illicit drugs
Parenting instruction for all new parents
Instruction in behavior therapy techniques for parents with children
children with MR and other
disorders
Treatments for Mental Retardation
1. Instruction
Using Behavioral Principles
Particularly useful for MR, because they teach and maintain skills
skills at each child’
child’s
level.
Caregivers are trained to teach children positive behaviors and reduce negative
behaviors effectively and humanely
Desired behaviors are modeled for imitation in incremental steps,
steps, with positive
reinforcement for successful performance at each step
SelfSelf-injurious behavior is ignored and placed on extinction if mild, followed by enforced
practice of better alternatives (overcorrection) if more severe
2.
3.
Drug Therapies
No drugs specifically aimed at MR, but some symptoms can be controlled
controlled
Neuroleptic drugs to reduce aggressive and antisocial behavior (phenothiazines
(phenothiazines,, Haldol)
Haldol)
Newer atypical antipsychotic drugs, such as risperidone,
risperidone, may be safer, but not tested for
children
Antidepressant drugs can improve sleep, possibly help reduce self
self-injurious behavior,
reduce depression.
Comprehensive Early Intervention Programs
May serve children at risk because of low birth weight, premature
premature birth, mild MR in the
family
Expert home visitors work with the family during first 3 years of
of child’
child’s life
Mothers given instruction and practice in ways to facilitate cognitive
cognitive and social development
and foster good physical health. Also stressstress-control for the mothers
Children in daily child development center with special education
education teachers and small groups
Parent support groups to help parents cope with the stresses of parenting
Gross, BrooksBrooks-Gunn, & Spiker (1992) found this program improved IQ scores, especially in the
lowest birth weight group. Effects continued at 60 and 90 months of age
4.
Mainstreaming
Placing children with MR in regular classrooms to “normalize”
normalize” their behavior and give them
more opportunities.
Effects are controversial. Studies show they are often shunned by
by regular students, may not
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receive the special education they need, and the poor and ethnically
ethnically different children are
too often mistakenly identified as MR
5.
Institutionalization
Reserved for the least capable children with the gravest disabilities
disabilities
A needed service, but too often neglected and underfunded by the States
SUMMARY
Mental Retardation is defined partly by an IQ score under approximately
approximately 70 and multiple
deficits in adaptive behavioral functioning in everyday life.
The DSM recognizes four levels of mental retardation as measured by IQ, ranging from mild
(the most frequent) to profound.
Mental Retardation can spring from many different biological and socialsocial-environmental
factors, with the most severe forms usually having biological roots.
roots. These include:
1. Metabolic disorders
2. Chromosomal Disorder
3. Prenatal Infections and Toxic Substances
4. Birth Injuries
5. Head Traumas
6. Many Others
Milder MR is usually treated with
1. Behavioral Instruction
2. Early Intervention Programs
3. Special Education
4. Mainstreaming
More severe MR is treated by:
1. Behavior Therapy
2. Drugs to control aggression and selfself-injurious behavior
3. Either home care or institutionalization
Wide availability of prenatal care for mothers and parenting instruction
instruction could significantly
reduce the occurrence of MR
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