DEVELOPMENTAL AND COGNITIVE DISORDERS
I. Common Developmental Disorders
A. Developmental psychopathology is the study of how disorders arise and change with
time. In general, childhood is associated with significant developmental changes that
follow a specific pattern. As a result, any disruption in the development of early skills will
likely disrupt the development of later skills.
B. The disorders covered in this chapter are usually diagnosed first in infancy, childhood, or
adolescence and include attention deficit/hyperactivity disorder (ADHD), learning
disorders, autism, and lastly mental retardation.
C. Attention deficit/hyperactivity disorder
1. The primary characteristics of persons with attention deficit/hyperactivity
disorder (ADHD) are inattention, overactivity, and impulsivity. Such persons
start many tasks but rarely finish them, have trouble concentrating, and do not
seem to pay attention when others speak. Children with ADHD are often
described as fidgety in school, and often are unable to sit still for more than a few
minutes. The textbook illustrates ADHD with the case of Danny.
2. The DSM-IV-TR differentiates two clusters of ADHD symptoms.
a. The first cluster includes problems of inattention.
b. The second cluster includes symptoms of hyperactivity and
c. Either the first (inattention) or the second (hyperactivity and impulsivity)
cluster must be present for the diagnosis of ADHD.
3. Inattention, hyperactivity, and/or impulsivity often result in other problems that are
secondary to ADHD. Examples include poor academic performance, unpopularity
and peer rejection, and low self-esteem resulting from frequent negative
feedback by parents and teachers.
4. ADHD is estimated to occur in 4% to 12% of children who are 6 to 12 years of
age, with boys outnumbering girls 4 to 1. Reasons for this large gender
difference are unknown. Children with ADHD are first identified as different from
their peers around age 3 or 4, and the symptoms of inattention, impulsivity,
and/or hyperactivity become increasingly obvious during the school years. 68%
of children with ADHD continue to have problems as adults, mostly with
inattention. The ADHD label is more likely to be used for children in the United
States than anywhere else.
5. The causes of ADHD have centered on genetics, brain damage, toxins and food
additives, and maternal smoking.
a. With regard to genetics, it has been known for some time that ADHD is
more common in families with one person having the disorder, and such
families display an increase in psychopathology in general, including
conduct disorder, mood disorders, anxiety disorders, and substance
abuse. More than one gene appears responsible for ADHD, leading
researchers to consider possible subtypes of ADHD.
i. Families with many persons with ADHD seem to have a very
specific deficit in the region of chromosome number 20.
ii. The gene for the D4 receptor — which appears involved in
novelty-seeking behavior — appears more often in children
iii. It is also suspected that the protein that assists with reuptake
of dopamine is involved in ADHD.
b. Brain damage has been implicated as a cause of ADHD for several
decades as reflected in use of labels such as "minimal brain damage" or
"minimal brain dysfunction."
i. Relative inactivity of the frontal cortex and the basal ganglia
have been associated with ADHD.
ii. Other evidence suggests right hemisphere malfunction, and
abnormal frontal lobe development and functioning.
iii. Research has yet to unearth precise neurological mechanisms
underlying the basic symptoms of ADHD. c. Toxins, such as allergens and food additives have been considered as
possible causes of ADHD, though there is little evidence for this link.
Yet, many families continue to put their children on fad diets (e.g., the
Feingold Diet), despite the absence of evidence that such diets help.
d. Maternal smoking during pregnancy results in a threefold increased
probability having a child with ADHD.
e. Psychological and social factors of ADHD also can influence the
disorder itself. For instance, impulsive and hyperactive behavior can
evoke negative responses by parents, teachers, and peers. Such
responses, in turn, may foster a low-self image in ADHD children.
6. Treatment of ADHD has proceeded on two fronts: biological and psychosocial
a. The goal of biological treatments is to reduce impulsivity and
hyperactivity and to improve attention.
i. Hundreds of studies have documented the effectiveness of
stimulant medication in reducing the core symptoms of ADHD.
Such medications include methylphenidate (Ritalin), d-
amphetamine (Dexedrine), and pemoline (Cylert). Such
medications are effective in 70% of cases. Cylert is
discouraged from use on a regular basis due to the greater
likelihood of negative side effects. Most common side effects
include insomnia, drowsiness, and/or irritability.
ii. Other drugs such as antidepressants (imipramine) and a drug
used to treat high blood pressure (clonidine) appear to offer
some therapeutic benefit.
iii. All of these drugs seem to improve compliance and decrease
negative behaviors in ADHD children, but they do not affect
learning and academic performance. The beneficial effects do
not last in the long term once drugs are discontinued.
iv. The paradoxical effects of stimulant medication are the similar
in children and adults with and without ADHD. Stimulant
medications reinforce the brain’s ability to focus attention
during problem-solving tasks. The theory that these
medications produce a paradoxical effect is not supported.
b. Behavioral interventions for ADHD involve reinforcement programs to
increase appropriate sitting, work, and play. Other programs incorporate
c. Most clinicians recommend a combination of biological and
psychological approaches to treat short-term management issues and
long-term concerns such as improving social skills and preventing and
reversing academic decline.
D. Learning disorders
1. Learning disorders cover problems related to academic performance in
reading, mathematics, and writing. Performance across such domains is
substantially below what would be expected given the person’s age, IQ, and
education. The textbook illustrates a reading disorder with the case of Alice.
a. DSM-IV-TR defines a reading disorder as a significant discrepancy
between a person’s reading achievement and what would be expected
for someone of the same age.
i. DSM criteria require that the person read at a level significantly
below that of a typical person of the same age, cognitive ability
(as measured with an IQ test), and educational background.
ii. The reading problem cannot be caused by a sensory deficit
such a trouble with sight or hearing.
b. Similarly, the DSM-IV-TR defines a mathematics disorder as
achievement below expected levels in mathematics.
c. The DSM-IV-TR disorder of written expression represents
achievement below expected levels in writing.
2. Definitions of learning disorders vary greatly, making estimates of incidence
and prevalence difficult. a. Conservatively, there is a 1% to 3% incidence of learning disorders in
the United States, with increased frequency of such disorders in
wealthier regions of the U.S.
b. The prevalence rate of learning disorders is 10% to 15% among school
c. Reading difficulties are the most common learning disorder, affecting
5% to 15% of the general population. Mathematics disorder appears in
6% of the population. Girls and boys are equally likely to be diagnosed
with reading disorder.
d. About 32% of students with learning disabilities drop out of school, and
employment rates for this group tend to be quite low.
e. Most adults with learning disabilities report that their school experiences
were generally negative, with such effects lasting beyond graduation.
3. Etiological theories of learning disorders include genetic, neurobiological, and
a. Regarding genetics, reading disorders tend to run in families, and the
concordance rate of reading disorders in identical twins is 100%.
i. Reading disorder may be linked to genetic material on
chromosome 6 and 15, but is likely influenced by several
biological and psychosocial factors.
b. Subtle forms of brain damage may be related to learning disabilities;
though findings are somewhat mixed.
4. Treatment for learning disorders requires intense educational intervention and
biological treatment and is typically restricted to those individuals who may also
5. Educational interventions focus on the following:
a. Remediation of the underlying basic processing problems (e.g.,
teaching students visual and auditory perception skills).
b. Improvement in cognitive skills through general instruction in
listening, comprehension, and memory.
c. Targeting behavioral skills needed to compensate for specific
problems in reading, math, or written expression.
d. Considerable research supports the usefulness of teaching behavioral
skills as a means to improve academic skills.
II. Pervasive Developmental Disorders
A. All persons with pervasive developmental disorders have problems with language,
socialization, and cognition. Pervasive means that the problems affect persons
throughout their lives, and includes autistic disorder, Asperger’s syndrome, Rett’s
disorder, childhood disintegrative disorder, and pervasive developmental disorder
— not otherwise specified. The textbook focuses on autistic disorder.
B. Autistic disorder, or autism, is a childhood disorder characterized by significant
impairment in social interactions and communication and by restricted patterns of
behavior, interest, and activities. The textbook illustrates autism with the case of Amy.
1. The DSM-IV-TR notes three major characteristics of autism: impairment in
social interactions, impairment in communication, and restricted behavior,
interests, and activities.
a. Persons with autism do not develop the types expected social
relationships expected for their age. Such problems are often more
qualitative than quantitative. Such persons are not totally unaware of
others, but they do not seem to enjoy meaningful relationships with
others or have the ability to develop them.
b. Persons with autism have severe problems with communication, with
about 50% never acquiring useful speech. Some with speech engage in
echolalia, and others are unable or unwilling to carry on conversations
c. Restricted patterns of behavior, interests, and activities are the
most striking aspects of autism. Many persons with autism prefer that
things remain the same; a phenomenon referred to as maintenance of
sameness. Such persons may also spend countless hours engaging in
stereotyped and ritualistic behaviors (e.g., spinning around in circles,
biting their hands). Prevention of such rituals may result in a severe
tantrum. 2. Autism is relatively rare, occurring in about 2 to 20 persons for every 10,000
a. Autism is more prevalent in females for people with IQs under 35, where
in the higher IQ range it is more prevalent in males. The reason for this
difference is unknown.
b. Autism occurs worldwide, and symptoms often develop before age 3.
c. About 50% of persons with autism have IQs in the severe to profound
range of mental retardation (i.e., IQ less than 50), about 25% test in the
mild-to-moderate IQ range (i.e., IQ of 50 to 70), and the remaining 25%
display abilities in the borderline-to-average range (i.e., IQ greater than
70). Better language skills and IQ test performance predicts better
3. Historically, numerous etiologic theories have been proposed to explain autism.
a. In the past, autism was viewed as the result of bad parenting. Such
parents were thought to be perfectionistic, cold, and aloof. Later
research has contradicted this view.
b. Other theories focused on unusual speech patterns; namely the
tendency to avoid first-person pronouns such as I and me and to use he
and she instead. This led to the view that autism may reflect a lack of
self-awareness. Later research shows that some people with autism do
have self-awareness and that such awareness follows a developmental
c. The characteristic idiot savant is not a usual feature of autism.
d. The phenomenon of echolalia (i.e., repeating a word or phrase spoken
by another person) was believed to be an unusual characteristic of this
disorder; however, this feature is also part of normal development.
e. The primary characteristic that clearly distinguishes persons with autism
from others is social deficiencies.
4. Biological dimensions of autism include the following:
a. Medical conditions, such as congenital rubella (i.e. German measles),
tuberous sclerosis, and difficulties during labor are not always
associated with autism.
b. Autism has a genetic component. Families with one child with autism
have a 3% to 5% risk of having another child with the disorder. The
exact genetic contribution is unknown.
c. Neurobiological evidence of brain damage is derived from the
observation that 3 of 4 people with autism have some level of mental
retardation, and 30% to 75% display neurological abnormalities such as
clumsiness or abnormal posture or gait.
d. CAT and MRI scans show abnormalities of the cerebellum, including
reduced size of this structure, among people with autism. This appears
to be one of the most reliable findings of brain involvement in autism to
C. Treatment for pervasive developmental disorders relies on a similar approach as used
with ADHD. The textbook largely focuses on the treatment of autism.
1. Psychosocial treatments for autism include behavioral approaches that focus
on skill building and treatment of problem behaviors. The behavioral approach is
based on the early work of Charles Ferster and Ivar Lovaas. The basic premise
is that people with autism can learn and can be taught skills. Targets for
treatment include the following:
a. Communication problems and problems with language are defining
characteristics of autism. The basic procedure involves shaping and
discrimination training to teach nonspeaking autistic children to imitate
others verbally. Alternative methods might include nonverbal gestures
b. Socialization deficits are profound in persons with autism, and yet
limited progress has been achieved toward developing interventions
that teach subtle social skills that are important for interactions with
peers and others.
c. Data suggest that early intervention is promising for children with
autism. Autistic children placed in regular classrooms tend to do better
than those placed in special education classes. 2. No biological or medical treatment exists to cure autism. In fact, medical
interventions have limited success.
3. Integrated treatments, combining several approaches, are the preferred
treatment of choice for people with pervasive developmental disorders.
a. In children, such treatment involves school education combined with
special psychological supports for problems with communication and
b. Parents likewise need support.
c. As children with autism grow older, intervention focuses on efforts to
integrate such individuals into their communities.
III. Mental Retardation
A. Mental retardation (MR) is a disorder of childhood that involves below-average
intellectual and adaptive functioning. Historically, persons with mental retardation have
been devalued by societies and their treatment has been shameful. Manifestations of
mental retardation are varied, with some individuals able to function well in society.
Persons with mild-to-moderate impairments (i.e., the majority of persons with MR) can,
with proper preparation, carry out most daily activities, whereas those with severe
impairments need help to carry out basic living tasks and may, with proper training,
achieve a degree of independence. Persons with MR experience impairments that affect
most areas of functioning, with language and communication skills being the most obvious
problem areas. The textbook illustrates mental retardation with the case of James.
B. The DSM-IV and DSM-IV-TR codes MR on Axis II, indicating that it is a chronic condition
and less amenable to treatment. DSM-IV-TR criteria for MR are arranged in three groups.
1. First a person must have significantly subaverage intellectual functioning as
determined by one of several IQ tests with a somewhat arbitrary cutoff score set
by the DSM-IV-TR at 70 or below. About 2% to 3% of the population score at or
below this cutoff.
2. Second, concurrent deficits or impairments in adaptive functioning must be
evident in at least two of the following areas: communication, self-care, home
living, social and interpersonal skills, use of community resources, self-direction,
functional academic skills, work, leisure, health, and/or safety.
3. The third criterion is age of onset. MR must be evident before the person is 18
years of age. This age criterion rules out the diagnosis of MR for adults who
suffer brain trauma or forms of dementia.
C. MR is largely defined by society and most classification systems (including the DSM-IV-
TR) identify four levels of MR.
1. Mild MR includes persons with an IQ score between 50 or 55 and 70.
2. Moderate MR includes persons in the IQ range of 35-40 up to 50-55.
3. Severe MR includes people with IQs ranging from 20-25 up to 35-40.
4. Profound MR covers people with IQ scores below 20-25.
D. The most controversial change in the American Association of Mental Retardation
(AAMR) definition of MR is its description of different levels of this disorder, based on the
level of assistance people need (i.e., intermittent, limited, extensive, or pervasive
assistance). The AAMR system identified the role of needed supports in determining level
of functioning, whereas the DSM-IV-TR implies that the ability of the person is the sole
determining factor of an MR diagnosis.
E. An additional classification method used in education systems to identify abilities of
persons with MR relies on three categories. Built into this system is the negative
assumption that certain individuals cannot benefit from certain types of training. This
system, and the potential stigma of the DSM, led to the AAMR categorization of needed
1. Educable mental retardation (i.e., IQ of 50 to approximately 70-75).
2. Trainable mental retardation (i.e., IQ of 30 to 50).
3. Severe mental retardation (i.e., IQ below 30).
F. About 90% of persons with MR get the label mild mental retardation, and persons with any
form of MR represent about 1% to 3% of the general population. The course of MR is
chronic; however, prognosis varies greatly. MR occurs more often in males, with a male-
to-female ratio being about 6:1, at least in cases of mild MR.
G. Etiologic research has identified hundreds of known causes of MR, including
environmental (e.g., abuse, deprivation), prenatal (e.g., exposure to disease, drugs, poor
nutrition), perinatal (e.g., difficulties during labor and delivery) and postnatal (e.g.,
infections, head injury). Despite the range of known causes, nearly 75% of cases cannot be attributed to any known cause or are thought to result from a combination of social and
1. Genetic research suggests that multiple gene influences are involved in MR. A
portion of people with severe MR have identifiable single-gene disorders,
involving dominant, recessive, or X-linked genes. Only a few dominant genes
result in MR, but can produce conditions related to MR (e.g., tuberous sclerosis,
phenylketonuria). Lesch-Nyhan syndrome is an X-linked disorder found only in
males characterized by MR, signs of cerebral palsy (i.e., spasticity or tightening
of the muscles), and self-injurious behavior.
2. Several chromosomal aberrations resulting in MR have been identified.
a. For example, Down syndrome is caused by an extra 21 chromosome
and is sometimes referred to as trisomy 21. This condition is caused by
the failure of cell division (i.e., nondisjunction) on chromosome 21,
resulting in one cell with one copy that dies and one cell with three
copies that divide to create a person with Down syndrome. Down
syndrome is associated with characteristic facial features, congenital
heart malformations, and dementia of the Alzheimer’s type in all adults
with Down syndrome past the age of 40. Incidence of Down syndrome
increases with the maternal age and risk of this condition can be
detected via amniocentesis.
b. Fragile X syndrome is a second common chromosomally related
cause of MR, related to an abnormality on the X chromosome. This
condition primarily affects males because they do not have a second X
chromosome with a normal gene to balance out the mutation. Female
carriers of fragile X syndrome commonly display mild-to-severe learning
disabilities. Males with fragile X show moderate-to-severe levels of MR,
higher rates of hyperactivity, short attention spans, gaze avoidance, and
perseverative speech. Physical characteristics include large ears,
testicles, and head circumference. About 1 of every 2,000 males is born
with fragile X syndrome.
3. Psychological and social factors that are thought to contribute to MR include
a. Cultural-familial retardation is believed to cause about 75% of MR
cases and is the least understood. Persons with this form of MR tend to
score in the mild MR range on IQ tests and have good adaptive skills.
Their MR is thought to result from a combination of psychosocial and
biological influences, such as abuse, neglect, and social deprivation.
According to the difference view, persons with cultural-familial
retardation have a limited subset of deficits (e.g., attentional or memory
problems) of those with severe forms of MR and are, therefore, more
like persons with severe MR but different from people without MR. The
developmental view conceptualizes mild MR in persons with cultural-
familial retardation as a difference in the rate and ultimate ceiling of an
otherwise normal developmental sequence. This later view suggests
that such children proceed through normal development, but at a slower
pace. Support for both views is mixed.
H. Treatment for MR parallels treatment of persons with pervasive developmental disorders
and attempts to teach such persons skills they need to become more productive and
independent. Biological treatment for MR is not a viable option.
1. For mild MR, interventions are similar to those used for learning disorders, and
include identification of learning deficits, assis