DISORDERS
USUALLY FIRST EVIDENT
IN INFANCY, CHILDHOOD, OR
ADOLESCENCE
Introduction
The disorders described in this
chapter are those that usually appear and are
first evident in infancy, childhood, or
adolescence. There is no arbitrary age limit
here that defines childhood and adolescence,
and this section includes some disorders
characteristic of older adolescents, such as
Bulimia Nervosa, which may first appear in
early adulthood.
In diagnosing an infant, child, or
adolescent, the clinician could first
consider the diagnoses included in this
section.
Because the essential features of Mood
Disorders and Schizophrenia are the same in
children and adults, there are no special
categories corresponding to these disorders
in this section of the classification.
Therefore, if, for example, a child or
adolescent has an illness that meets the
criteria for Major Depression, Dysthymia, or
Schizophrenia, these diagnoses should be
given, regardless of the person's age. (In
some instances, age-specific associated
features that apply to infants, children, or
adolescents are included in the text.)
Other diagnostic categories that
are often appropriate for children and
adolescents are the following:
Organic Mental Disorders Psychoactive
Substance Use Disorders
Schizophrenia
Mood Disorders
Schizophreniform Disorder
Somatoform Disorders
Sexual Disorders
Adjustment Disorder
Psychological Factors Affecting Physical
Condition
Personality Disorders
Adults should be given diagnoses from this
section if, as infants, children, or
adolescents, they had symptoms of any of
these disorders and the condition has
persisted. Examples include the residual
phase of Attention-deficit Hyperactivity
Disorder and some cases of Conduct Disorder.
Finally, some people may develop in adulthood
a disorder, such as Anorexia Nervosa, that is
included in this section because the disorder
usually first develops in children or
adolescents.
Many children who come to clinical
attention have problems that do not warrant a
diagnosis of a mental disorder, such as
Parent-Child Problem, Childhood or Adolescent
Antisocial Behavior, or Other Specified
Family Circumstances.
Children who are psychologically, physically,
or sexually abused may react in a variety of
ways. If the reaction constitutes a mental
disorder, the following categories should be
considered: Reactive Attachment Disorder of
Infancy or Early Childhood, Post-traumatic
Stress Disorder (generally for the older
child), and Adjustment Disorder.
DEVELOPMENTAL
DISORDERS
The essential feature of this
group of disorders is that the predominant
disturbance is in the acquisition of
cognitive, language, motor, or social skills.
The disturbance may involve a general delay,
as in Mental Retardation, or a delay or
failure to progress in a specific area of
skill acquisition, as in Specific
Developmental Disorders, or multiple areas in
which there are qualitative distortions of
normal development, as in the Pervasive
Developmental Disorders.
The course of the Developmental Disorders
tends to be chronic, with some signs of the
disorder persisting in a stable form (without
periods of remission or exacerbation) into
adult life. However, in many mild cases,
adaptation or full recovery may occur.
MENTAL
RETARDATION
The essential features of this disorder
are:
- significantly subaverage general
intellectual functioning, accompanied
by
- significant deficits or impairments
in adaptive functioning, with
- onset before the age of 18.
The diagnosis is made regardless of
whether or not there is a coexisting physical
or other mental disorder.
General intellectual functioning.
General intellectual functioning is defined
as an intelligence quotient (IQ or IQ
equivalent) obtained by assessment with one
or more of the individually administered
general intelligence tests (e.g., Wechsler
Intelligence Scale for Children-Revised,
Stanford Binet, Kaufman Assessment Battery
for Children). Significantly subaverage
intellectual functioning is defined as an IQ
of 70 or below on an individually
administered lQ test. Since any measurement
is fallible, an IQ score is generally thought
to involve an error of measurement of
approximately five points; hence, an IQ of 70
is considered to represent a band or zone of
65 to 75.
Treating the IQ with some flexibility permits
inclusion in the Mental Retardation category
of people with IQs somewhat higher than 70
who exhibit significant deficits in adaptive
behavior. It also permits exclusion from the
diagnosis of those with lQs somewhat lower
than 70 if the clinical judgment is that
there are no significant deficit or
impairments in adaptive functioning. An IQ
level of 70 was chosen because most people
with IQs below 70 require special services
and care, particularly during the school-age
years.
The arbitrary IQ ceiling values are based on
data indicating a positive association
between intelligence (as measured by IQ
score) and adaptive behavior at lower IQ
levels. This association declines at the mild
and moderate levels of Mental Retardation.
Adaptive functioning.
Adaptive functioning refers to the person's
effectiveness in areas such as social skills,
communication, and daily living skills, and
how well the person meets the standards of
personal independence and social
responsibility expected of his or her age by
his or her cultural group. Adaptive
functioning in people with Mental Retardation
(and in people without Mental Retardation) is
influenced by personality characteristics,
motivation, education, and social and
vocational opportunities. Adaptive behavior
is more likely to improve with remedial
efforts than is IQ, which tends to remain
more stable.
Useful scales have been designed to quantify
adaptive functioning or behavior (e.g., the
Vineland Adaptive Behavior Scales, American
Association of Mental Deficiency Adaptive
Behavior Scale). Ideally, these scales should
be used in conjunction with a clinical
judgment of general adaptation. If these
scales are not available, clinical judgment
of general adaptation alone, the person's age
and cultural background being taken into
consideration, may suffice.
Associated features. When
a specific physical disorder is associated
with Mental Retardation, the features of the
physical disorder will, of course, also be
present. For example, in cases of Mental
Retardation associated with Down syndrome,
the physical features of Down syndrome will
be present. The more severe the Mental
Retardation (especially if it is severe or
profound), the greater the likelihood of
associated abnormalities in one or more
systems, such as the neurologic (e.g.,
seizures), Neuromuscular, visual, auditory,
and cardiovascular systems. These
abnormalities may further impair the person's
adaptive functioning. It should be noted,
however, that in Mental Retardation
associated with Down syndrome,, social skills
are likely to be higher than would he
expected by the level of Mental Retardation.
Behavioral symptoms commonly seen in Mental
Retardation include passivity, dependency,
low self-esteem, low frustration tolerance,
aggressiveness, poor impulse control, and
stereotyped self-stimulating and
self-injurious behavior. In some cases, these
behaviors may be learned and conditioned by
environmental factors; in other cases, they
may be linked to an underlying physical
disorder, such as self-injurious behavior
associated with Lesch-Nyhan syndrome. At the
present time there is no satisfactory
subclassification of behavioral symptoms
associated with Mental Retarda¬ tion.
The prevalence of other mental disorders is
at least three or four times greater among
people with Mental Retardation than in the
general population. Particularly common as
associated diagnoses are Pervasive
Developmental Disorders, Attention-deficit
Hyperactivity Disorder, and Stereotypy/Habit
Disorder.
Age at onset. By
definition, Mental Retardation requires that
onset be before age 18. When a similar
clinical picture develops for the first time
after the age of 18, the syndrome is a
Dementia, not Mental Retardation. An example
would be a 19-year-old with previously normal
intelligence who developed the clinical
picture of Mental Retardation after
sustaining brain damage in an automobile
accident. However, a Dementia can be
superimposed on previously existing Mental
Retardation. An example would be a child with
mild Mental Retardation whose functioning
deteriorates after sustaining brain damage in
an automobile accident. When the clinical
picture develops before the age of 18 in a
person who previously had normal
intelligence, Mental Retardation and Dementia
should both be diagnosed.
Course. The course of
Mental Retardation is a function of both
biologic factors, such as an underlying
etiologic physical disorder, and
environmental factors, such as educational
and other opportunities, environmental
stimulation, and appropriateness of
management. If the underlying physical
abnormality is static (as in fragile X
syndrome), the course of the Mental
Retardation is variable: with good
environmental influences, functioning may
improve; with poor environmental influences,
it may deteriorate. If the underlying
physical abnormality is progressive (as in a
lipid storage disorder), functioning will
tend to deteriorate, although with good
environmental influences, the deterioration
may proceed more slowly.
As a rule, children with Mental Retardation
are no longer admitted to custodial-type
institutions, and adults with Mental
Retardation are only rarely thus
institutionalized. As a result, the prognosis
for Mental Retardation has improved
dramatically in recent years. The majority of
people with Mental Retardation now adapt well
to life in the community, within the limits
of their handicap.
Some people with mild Mental Retardation
develop good adaptive skills and maintain
jobs in competitive employment. For such
people the diagnosis of Mental Retardation
may no longer be justified, even if it was
appropriate when they were of school age and
their intellectual deficits limited their
academic functioning.
Impairment. By
definition, there is always impairment in
adaptive functioning. The degree of
impairment is correlated with the level of
general intellectual functioning, the
presence of associated features and
complications, and educational and other
environmental opportunities.
Complications. Other
mental disorders, such as Depressive
Disorders, psychotic disorders, and
Personality Disorders, may be complications.
The diagnosis of other mental disorders may
be difficult because of cognitive and
language deficits that may mask the clinical
manifestations of the other disorders. For
example, a person with Mental Retardation may
have difficulty verbalizing depressive
thoughts and feelings. For nonverbal people
with Mental Retardation, the nonspecific
diagnostic categories (e.g., Depressive
Disorder Not Otherwise Specified), rather
than the specific ones, may have to be
employed.
People with Mental Retardation are
particularly vulnerable to exploitation by
others, such as being physically and sexually
abused or being denied rights and
opportunities.
Etiologic factors and familial
patterns. Etiologic factors may be
primarily biologic, psychosocial, or a
combination of both. In approximately 30%-40%
of the cases seen in clinical settings, no
clear etiology can be determined despite
extensive evaluation efforts. The following
are the major causative factors in the
remaining cases:
- hereditary factors (in approximately
5% of cases), such as inborn errors
of metabolism (e.g., Tay-Sachs
disease), other single-gene
abnormalities (e.g., tuberous
sclerosis), and chromosomal
aberrations (e.g., translocation Down
syndrome);
- early alterations of embryonic
development (in approximately 30%),
such as chromosomal changes (e.g.,
trisomy 21 syndrome), prenatal damage
due to toxins (e.g., maternal alcohol
consumption, infections) or unknown
causes;
- pregnancy and per natal problems (in
approximately 10%), such as fetal
malnutrition, prematurely, hypoxia,
trauma;
- physical disorders acquired in
childhood (in approximately 5%), such
as infections, traumas, and lead
poisoning;
- environmental influences and mental
disorders (in approximately 15%-20%),
such as deprivation of nurturance and
of social, linguistic, and other
stimulation, and complications of
severe mental disorders (e.g., a drop
in adaptive functioning in a person
with a borderline level IQ following
early-onset Schizophrenia).
The prevalence of Mental Retardation due
to known biologic factors is similar among
children of upper and lower socioeconomic
classes, except that certain etiologic logic
factors are linked to lower socioeconomic
status, such as lead poisoning and premature
births. In cases in which no specific
biologic causation can be identified, lower
socioeconomic classes are overrepresented,
and the Mental Retardation is usually milder
(but all degrees of severity are
represented).
The age at which a diagnosis of Mental
Retardation is first made in a person depends
on the degree of its severity and whether a
physical disorder with characteristic
phenotypic features is present. thus,
children with Severe Mental Retardation and
children with Down syndrome are diagnosed
earlier than children with mild retardation
of unknown cause.
Prevalence. Recent
studies suggest that at any one point in
time, the prevalence rate of Mental
Retardation is approximately 1%.
Sex ratio. Mental
Retardation is more common among males, with
a male:female ratio of approximately 1.5:1.
Differential diagnosis.
The diagnosis of Mental Retardation should be
made when the criteria are met, regardless of
the presence of another diagnosis. In
Specific Developmental Disorders
(unassociated with Mental Retardation) there
is a delay or failure of development in a
specific area, such as reading or language,
but in other areas of development the child
is developing normally. in contrast, a child
with Mental Retardation always has general
delays in development in many areas.
In Pervasive Developmental Disorders there is
qualitative impairment in the development of
rec iprocal social interaction, in the
development of verbal and nonverbal
communication skills, and in the development
of imaginative activity. These abnormalities
are not normal for any stage of development,
whereas in Mental Retardation (unassociated
with ano ther disord er) there are
generalized delays in development, but the
person behaves as if he or she were passing
through an earlier normal developmental
stage.
Mental Retardation may, however, coexist with
Specific Developmental Disorders (e.g., a
severe language deficit out of proportion to
other areas of development in an person with
Mild Mental Retardation). People with a
Pervasive Developmental Disorder also
frequently have Mental Retardation.
The V code Borderline intellectual
Functioning is given when there is borderline
intellectual functioning, which generally is
in the IQ range of 71 to 84, and the
diagnosis of Mental Retardation is not
warranted. Differentiating Mild Mental
Retardation from Borderline Intellectual
Functioning requires careful consideration of
all available information, including
psychological test scores.
Diagnostic criteria for Mental
Retardation
A. Significantly subaverage
general intellectual functioning: an IQ of 70
or below on an individually administered IQ
test (for inf ants, a c linical judg ment of
significantly subaverage intellectual
functioning, since available intelligence
tests do not yield numerical lQ values)
B. Concurrent deficits or
impairments in adaptive functioning, i.e.,
the person's effectiveness in meeting the
standards expected for his or her age by his
or her cultural group in areas such as social
skills and responsibility, communication,
daily living skills, personal independence,
and self-sufficiency.
C. Onset before the age of
18.
Degrees of severity.
There are four degrees of severity,
reflecting the degree of intellectual
impairment: Mild, Moderate, Severe, and
Profound. IQ levels to be used as guides in
distinguishing the four degrees of severity
are:
Degree of severity
Mild
Moderate
Severe
Profound
IQ
50-55 to approx. 70
35-40 to 50-55
20-25 to 35-40
Below 20 or 25
Mild Mental Retardation
Mild Mental Retardation is roughly equivalent
to what used to be refereed to as the
educational category of "educable."
This group constitutes the largest segment of
those with the disorder about 85%. People
with this level of Mental Retardation
typically develop social and communication
skills during the preschool years (ages 0-5),
have minimal impairment in sensorimotor
areas, and often are not distinguishable from
normal children until a later age. By their
late teens they can acquire academic skills
up to approximately sixth-grade level; during
their adult years, they usually achieve
social and vocational skills adequate for
minimum self-support, but may need guidance
and assistance when under unusual social or
economic stress. At the present time,
virtually all people with Mild Mental
Retardation can live successfully in the
community, independently or in supervised
apartments or group homes (unless there is an
associated disorder that makes this
impossible).
Moderate Mental Retardation
Moderate Mental Retardation is roughly
equivalent to what used to be referred to as
the educational category of
"trainable." This former term
should not be used since it wrongly implies
that people with Moderate Mental Retardation
cannot benefit from educational programs.
This group constitutes 10% of the entire
population of people with Mental Retardation.
Those with this level of Mental Retardation
can talk or learn to communicate during the
preschool years. They may profit from
vocational training and, with moderate
supervision, can take care of themselves.
They can profit from training in social and
occupational skills, but are unlikely to
progress beyond the second grade level in
academic subjects. They may learn to travel
independently in familiar places. During
adolescence, their difficulties in
recognizing social conventions may interfere
with peer relationships. In their adult
years, they may be able to contribute to
their own support by performing unskilled or
semiskilled work under close supervision in
sheltered workshops or in the competitive job
market. They need supervision and guidance
when under stress. They adapt well to life in
the community, but usually in supervised
group homes.
Severe Mental Retardation
This group constitutes 3%-4% of people with
Mental Retardation. During the pre¬ school
period, they display poor motor development,
and they acquire little or no communicative
speech. During the school-age period, they
may learn to talk, and can be trained in
elementary hygiene skills. They profit to
only a limited extent from instruction in
pre-academic subjects, such as familiarity
with the alphabet and simple counting, but
can master skills such as learning
sight-reading of some "survival"
words, such as "men" and
"women" and "stop." In
their adult years, they may be able to
perform simple tasks under close supervision.
Most adapt well to life in the community, in
group homes or with their families, unless
they have an associated handicap that
requires specialized nursing or other care.
Profound Mental Retardation
This group constitutes approximately 1 %-2%
of people with Mental Retardation. During the
early years, these children display minimal
capacity for sensorimotor functioning. A
highly structured environment, with constant
aid and supervision, and an individualized
relationship with a caregiver are required
for optimal development. Motor development
and self-care and communication skills may
improve if appropriate training is provided.
Currently, many of these people live in the
community, in group homes, intermediate care
facilities, or with their families. Most
attend day programs, and some can perform
simple tasks under close supervision in a
sheltered workshop.
Unspecified Mental Retardation
This category should be used when there is a
strong presumption of Mental Retardation but
the person is untestable by standard
intelligence tests. This may be the case when
children, adolescents, or adults are too
impaired or uncooperative to be tested. It
may also be the case with infants when there
is a clinical judgment of significantly
subaverage intellectual functioning, but the
available tests, such as the Bayley, Cattle,
and others, do not yield IQ values. In
general, the younger the age, the more
difficult it is to make a diagnosis of Mental
Retardation, except for those with profound
impairment.
This category should not be used when the
intellectual level is presumed to be above 70
Page
2
Back to Special
Needs Index
