Mental retardation occurs in about 2% of general population
Mental retardation poses significant problems for society
Mental Retardation
Mental retardation as defined by DSM-IV-TR has three criteria
Significantly subaverage general intellectual functioning
Significant limitations in adaptive functioning in at least two
adaptive skills areas
Onset before 18 years of age
Definition has several important components
Adaptive functioning refers to person's ability to cope with
life's demands and live independently according to standards of age
group, community, social class, and culture
Diagnosis requires deficits in both intellectual and adaptive
functioning
Diagnosis made in context of age-mates
Definition says nothing about cause
Levels of Mental Retardation
In intelligence tests, 100 is average, with standard deviation
(SD) of 15
Cutoff point is an IQ of about 70
There are several levels of mental retardation
Mild Retardation includes 85% of all cases
IQ of 50-55 to 70
Need more help longer with self-care tasks
Speak fluently and function independently in most areas
Can hold job, marry, and have children
Moderate Retardation
IQ of 35-40 to 50-55
By adolescence, have good self-care skills
Carry on simple conversations, read few words, and do simple
tasks
Severe Retardation
IQ of 20-25 to 35-40
Can learn some self-care skills
Can perform jobs in sheltered workshop or daytime activity
center
Require considerable supervision
May have trouble speaking; reading and number skills not sufficient
for normal living
Profound Retardation
IQ below 20 or 25
Can carry out some self-care activities
Requires extensive supervision and help
Language is severe problem
Many remain institutionalized
Susceptible to disease
AAMR suggests not using IQ criterion until deficits in adaptive
functioning have been established
AAMR recommends classification based on levels of required support
or assistance
Mild retardation indicated by need for intermittent assistance
Moderate retardation associated with limited assistance
Severe retardation indicated by extensive assistance
Profound retardation indicated by pervasive assistance
Genetic Factors
Mechanism that produces retardation is not understood
Two people may have same mediate diagnosis but be at different
levels of retardation
Differential diagnosis is a problem
Chromosomal Abnormalities
Certain forms of mental retardation are X-linked
Fragile X syndrome involves weak spot where chromosome
is bent or broken
Pronounced physical characteristics
Many are hyperactive and show characteristics of autism
In men, disorder has more severe consequences
Down syndrome includes physical characteristics
IQs less than 50
Susceptible to serious cardiac and respiratory diseases
Extra chromosome on pair 21, or Trisomy 21, in
most cases
"Fragile X" syndrome and Down syndrome account for one-fourth
of all cases of mental retardation
Genetic counseling can provide guidance and testing
Risk for Down syndrome related to mother's age
Amniocentesis involves analyzing amniotic fluid
Routinely given to pregnant women over 35
Metabolic Disturbances
Phenylketonuria (PKU) caused by defective recessive
gene
Child cannot metabolize amino acid phenylalaline
Phenylalaline accumulates in body and damages CNS
Most states require PKU testing of newborns
Tay-Sachs disease transmitted by recessive genes
Characterized by progressive deterioration
Is untreatable
Death is virtually certain before age of six
Environmental Factors
Prenatal Environment
Congenital Disorders
Congenital disorders are acquired during prenatal
development but are not transmitted genetically
Until recently, three common congenital causes were rubella,
syphilis, and thyroxine deficiency
Most common congenital cause today is transmission of
HIV virus leading to encephalopathy, meningitis, and lymphoma
leading to developmental delays
Drugs
Thalidomide prescribed for morning sickness, caused mental
retardation and severely malformed limbs
Fetal alcohol syndrome (FAS) associated with drinking
during pregnancy; causes distinctive facial characteristics
and mental retardation with IQs between 40 and 80
Illegal drugs have profound effect on fetal brain; crack
babies likely to show retarded growth and brain development
affected
There is interaction of prenatal and postnatal environments
Malnutrition
Prenatal malnutrition affects physical and behavioral
development
Iron-deficiency anemia stunts physical growth causing
developmental delays and contributes to behavior problems
Combination of dietary supplements and stimulation required
to overcome nutritional deficits
Malnutrition often seen with other retardation-associated
factors
Postnatal Environment
Toxins
Substances can enter child's bloodstream and cause retardation
DPT vaccination, in very small number of children, can
cause brain damage
Lead poisoning has higher risk; deposits accumulate
and interfere with brain cell metabolism causing damage
Physical Trauma
Trauma to brain as result of accident or abuse can cause
mental retardation
Brain can also be harmed during birth due to compression,
use of forceps, and hypoxia
The Effects of Deprivation
Disproportionately high number of children from disadvantaged
backgrounds are retarded
Some cases may be due to growing up in deprived setting
Impoverishment called pseudoretardation; may
be emotionally based, not intellectual
What began as psychological factors may become physical
factors
Brain plasticity suggests that experiences can
alter structure and function of brain
Brain growth and development occurs very early
Barren, deprived environment may produce a less efficient
brain
Effects of poor environment may not be reversible and
may be cumulative; children raised in poverty are at risk
Teenage Mothers
Teenage mothers rarely equipped to raise children
Underlying competence is the mother's own adolescent
struggles
They are less sensitive to child's cues, less likely
to interact with child verbally, more likely to criticize
and punish them
Children are exposed to factors associated with developmental
disabilities
Average IQ of teenage mother is 85
Mild retardation appears more often in children of teenage
mothers
Institutionalization
A lack of stimulation interaction with children who are institutionalized
may be related to retardation
Study suggests that institutionalized child showed significant
average loss in developmental quotient
Effects dependent on kind and quality of institutional care
Mental Retardation in Adults
Down Syndrome and Alzheimer's Disease
In past, people with Down syndrome didn't live past middle
age
More and more people with Down syndrome are surviving into
old age
There is a link between Down syndrome and Alzheimer's disease
Alzheimer's disease strikes early
Onset is marked by behavioral regression
Mental Retardation and Other Mental Disorders
Mentally retarded people at risk for other mental disorders
When IQ is over 50, symptoms of emotional disturbance are
like those of normal intelligence
When IQ is lower, emotional disturbance is harder to detect
Social position may put mentally retarded at risk
Most people with mental retardation do not get treatment since
emotional dysfunction is often ignored
Groups at Risk for Mental Retardation
Gender is risk factor for mental retardation with males outnumbering
females
Age is risk factor; mental retardation peaks at age five or six
years
Socioeconomic status related to parental intelligence and amount
of stimulation child receives
Mild retardation more prevalent in families with low incomes
Severe retardation does not seem to be related to socioeconomic
status
Minority group status also related factor
Prenatal and perinatal variables are major risk factors
Autism
Kanner argued that autism was distinct syndrome different from
schizophrenia
Kanner called syndrome early infantile autism
Believed autism was inborn and appeared by age two and a half
years
Most psychotic disorders of children considered instances of autism
Symptoms of Autism
Social Isolation
People with autism have impaired social behavior, sometimes
called extreme autistic aloneness
They do not demand attention
Difficult to hold and cuddle
Recoil from personal contact
Behave as if others do not exist
Degree of social isolation varies
Children with autism do show emotions such as rage, panic,
and crying
Appears to be three types of autism based on social behavior
Aloof type whereby child rarely makes spontaneous social
approach
Passive type whereby child does not initiate contact
but does respond to someone else's initiation of contact
Active-but-odd type whereby child approaches others
in peculiar, naïve, or one-sided way
Autism may be several disorders, instead of just one
Mental Retardation
Most children with autism are mentally retarded with 76-89%
of children having IQ of less than 70
There are differences in the nature of cognitive deficits
of autistic and mentally retarded children
Autistic children do better on finding hidden figures
than on social understanding and language
Mentally retarded perform more evenly on all such tests
Mental retardation in autism is primary cognitive problem,
not result of social withdrawal
Some autistic children do show signs of above-average intelligence
in one limited area; these are called savants
Language Deficits
More than half of all children with autism do not speak at
all
Others babble, whine, scream, or show echolalia
Those who do speak use language in limited ways
Strange use of pronouns
Some speak extremely literally
Some cannot communicate reciprocally
Severity of language problem is excellent indicator of prognosis
with children most likely to benefit from treatment: those who
have developed some meaningful speech by age of five years
Intellectual development is also excellent indicator of prognosis
Stereotyped Behavior
Many autistic children show movements that are endlessly and
ritualistically done without any clear goal
Twirling, tiptoeing, flapping hands, rocking, tensing part
of face are common stereotyped behavior
Some movements can cause physical harm
Children engage in these behaviors to communicate desires
and to obtain certain kinds of reinforcement such as sensory reinforcement,
attention, and positive tangible reinforcement
Many children also show intense and narrow focus with toys,
objects
Children with autism also resist any change in surroundings
and routines
Some autistic people grow up to hold down jobs and live alone,
but they experience language problems and social adjustment problems
Theories of Autism
Explanations of autism have changed radically in past decades;
in 1950s and 1960s focus was on cold, rejecting parents
The Biological Perspective
Genetic Research
Twin studies suggest genetic basis of autism; more MZ
than DZ twins are concordant
Other studies show relationships between siblings with
mental retardation and autism
Chromosome Studies
Fragile X syndrome associated with autism
Other abnormalities such as tuberose sclerosis and chromosomal
abnormalities on 15 associated with autism
Biochemical Studies
Study suggests that children with autism do not have abnormally
high levels of serotonin and dopamine
Drugs that increase dopamine worsen symptoms
Drugs that inhibit dopamine mitigate many of the symptoms,
but less effective than with schizophrenia
Congenital Disorders and Birth Complications
Several birth complications appear to be related to autism
Relationship may not be cause-and-effect
Congenital disorders may be related to genetic factors
Neurological Research
Autism probably results from range of deficits in brain
Symptoms are related to functioning of CNS
Many autistic children develop seizure disorders
Half of persons with autism display abnormal EEGs
Autistic children show reduced EEG activity in frontal
and temporal regions of brain
Autopsies reveal certain abnormalities in cerebellum
and limbic system such as neuronal and dendrite abnormalities
and megalencephaly
Brain-imaging techniques have identified differences
such as enlarged ventricles
The Cognitive Perspective
Cognitive problems of autistic children are primary and cause
their social problems
People with autism have problems associated with executive
functioning such as problem solving, controlling impulses, and
inhibiting inappropriate behavior
Research on categorization and memory show that autistic people
have difficulty forming new concepts and understanding new information
based on those concepts, in particular, forming prototypes to
categorize objects leading to over-reliance on rules
Social understanding is impaired, for example, comprehending
gestures and understanding others' emotions and facial expressions
Some argue that autistic people have no theory of mind
Autistic people cannot appreciate existence of purely
mental states
Cannot predict or understand behavior based on such
states
Groups at Risk for Autism
Socioeconomic status and ethnocultural background are not
major risk factors
Gender is a significant risk factor and may be related to
risk factors for mental retardation
Presence of autism in sibling is another risk factor suggesting
genetic influences
Society and People with Developmental Disabilities
Public Policy
Parent groups have vigorously lobbied governments for increased
funding and legislation regarding the rights to free education
Groups have taken their grievances to federal and state courts;
decisions have altered treatment of people with retardation
Number of professionals in field of mental retardation has expanded
greatly
There are five basic principles regarding the rights of mentally
retarded people
Free and appropriate education
Individualization
Timely progress reviews
Community integration
Human rights
Public Law 94-142 guarantees every citizen under 21 years a free
and appropriate public education
Programs are tailored to individual's needs in individualized
education program (IEP)
Multidisciplinary conferences used to review progress of special
education student
Innovative programs such as the cascade system have been developed
Community Integration
Segregation of services deprived people with mental retardation
of participation in society
Community integration provides services for the mentally retarded
than are integrated with same services for people without mental retardation;
example is mainstreaming
Assisted-living arrangements are available, including supported
living arrangements, community living facilities, and intermediate-care
facilities; designed for care of people who function on different
levels
Large-scale institutions are for individuals who cannot function
satisfactorily in community settings; more and more individuals are
being moved out of these large institutions
Quality of Life
Quality of life is a multidimensional concept that includes physical,
material, social, emotional well-being, personal development, and
activity
Research has focused on providing choices to people with developmental
disabilities; choice appears to correlate with adaptive and maladaptive
behavior
Support for the Family
Most family are given recommendation for child to be cared for
at home
Families need supportive training and counseling
Retarded children have same needs as normal children but also
have special needs
Home training can help parents deal with special needs
Training also improves parent-child bond
Adolescents with mental retardation present additional concerns
Parents must balance child's need for independence and child's
lack of maturity
Concerns are greatest when child has mild and moderate mental
retardation
As person enters adulthood, family must consider extent to which
individual can live independently
A more human approach to sex and marriage among the mentally retarded
has emerged
People with mental retardation have right to sexual development
and education about AIDS and HIV
Sterilization is the last resort
Employment
People with mental retardation must have opportunities for useful
employment according to federal and state law
People with mental retardation must be given planned daytime
programs or supported employment
Severely or profoundly mentally retarded individuals placed
in sheltered workshops for employment tailored to their
needs
Most people with mental retardation want to work and can become
good employees
When people with mental retardation are fired it is usually
for lack of social skills
Prevention and Therapy
Primary Prevention
Couples at risk for genetic factors related to mental retardation
can be identified, informed of the risk, and advised
A simple blood test can identify carriers of Tay-Sachs disease,
and genetic analysis can identify abnormalities in developing fetus
Secondary Prevention
When child poses risk for condition that could lead to mental
retardation, secondary prevention attempts to reduce risk
Medical procedures can be attempts at secondary prevention
Psychological therapies such as providing stimulation and teaching
parents are used to reduce risk
Programs have been developed to provide stimulation for infants
whose only apparent risk factor is poverty
Behavior Therapy
Behavioral techniques used extensively and with good success
There are three basic techniques for behavior therapy
Shaping--reinforcing successive approximations of desirable
behavior
Chaining--teaching person to finish task and gradually expand
number of steps to finish
Stimulus control--teaching that a behavior should occur in
some situations but not in others
Self-Help and Adaptive Skills
Training in self-help and adaptive skills teaches daily living
skills
Type of training involves several steps
Breaking down of task into small steps
Backward or forward chaining
iii. Substantial feedback and reinforcement
Token economies have been especially successful in vocational
training programs and social behavior
Behavior therapy is most appropriate and effective technique
for teaching self-help skills to those with severe mental retardation
Toilet training, using behavioral techniques, improves hygiene
and promotes social interaction
Language and Communication Skills
One of most important applications of behavior therapy has
been in language acquisition
Step-by-step behavioral sequences appear to be useful
Shaping and verbal imitation typically used to train people
who are mute; sign language and picture books also used
Training in communication improves prognosis and reduces behavior
problems
Leisure and Community Skills
Modeling, prompting, providing feedback, and reinforcement
used to improve quality of life
Children's insensitivity to social reinforcement must be conquered
Replacement of Maladaptive Behaviors
Aggression and self-injury treated with time-outs, differential
reinforcement of other behavior, and differential reinforcement
of incompatible behavior
Effectiveness depends on what behavior is being eliminated
as the function of the behavior
Any change in behavior must be supported by the environment
Aim of behavior therapy is to provide these children with
enough adaptive responses so they can move to a more useful and
fulfilling existence
Critics suggest that children become like robots
Cognitive Therapy
Self-instructional training refers to development of self-regulatory
speech that is useful in academic, leisure, and vocational skills
Correspondence training involves use of rewards for action-oriented
verbal statements
Self-management and self-monitoring teach individuals to regulate
own behavior, to evaluate performance, and to reward themselves accordingly
Training in self-control involves delayed gratification of impulses
Problem-solving training focuses on defining problem, developing
solutions, and choosing best solutions
Pharmacological Therapy
Pharmacology is commonly used for people with developmental disabilities
Psychotropic drugs and anticonvulsive medications are common
Serotonin-reducing drugs have been used to treat autism but may
not be helpful in treating core social and language deficits
Psychotherapy
It has been assumed that people with mental retardation could
not benefit from psychotherapy
There are now many forms of psychological treatment, such as supportive
psychotherapy, group psychotherapy, family therapy, and client-centered
therapy, that can help
Marital counseling and parent training may be useful for those
planning to marry and raise a family
