PERVASIVE
DEVELOPMENTAL DISORDERS
The disorders in this subclass are
characterized by qualitative impairment in
the development of reciprocal social
interaction, in the development of verbal and
nonverbal communication skills, and in
imaginative activity. Often there is
a markedly restricted repertoire of
activities and interests, which frequently
are stereotyped and repetitive. The severity
and expression of these impairments vary
greatly from child to child.
These disorders frequently are associated
with a variety of other conditions.
Distortions or delays in development are
common in the following areas; intellectual
skills, as measured by standardized
intelligence tests (in most cases there is an
associated diagnosis of Mental Retardation);
comprehension of meaning in language and the
production of speech (in addition to problems
in the social use of speech for reciprocal
communication); posture and movements;
patterns of eating, drinking, or sleeping;
and responses to sensory input.
Various diagnostic terms, including Atypical
Development, Symbiotic Psychosis, Childhood
Psychosis, Childhood Schizophrenia, and
others, have been used to describe these
disorders in the past. However, clinical
descriptions have typically over-lapped; and
apart from Autistic Disorder, no generally
recognized subtypes have yet emerged. Though
some early investigators suggested that these
disorders were continuous with adult
psychoses (e.g., Schizophrenia), substantial
research suggests that they are unrelated to
the adult psychoses. For that reason, and the
difficulties of assessing psychosis in
childhood, the term psychosis has not been
used here to label this group of disorders:
Pervasive Developmental Disorders is used
because it describes most accurately the core
clinical disturbance in which many basic
areas of psychological development are
affected at the same time and to an even
degree.
This classification recognizes only one
subgroup of the general category Pervasive
Developmental Disorders: Autistic Disorder,
also known as Infatile Autism and Kanner's
syndrome. The evidence suggests, however,
that this disorder is merely the most severe
and prototypical form of the general category
Pervasive Developmental Disorders. Cases that
meet the general description of a Pervasive
Developmental Disorder but not the specific
criteria for Autistic Disorder are diagnosed
as Pervasive Developmental Disorder Not
Otherwise Specified (PDDNOS). Whereas in
clinical settings Autistic Disorder is more
commonly seen than PDDNOS, studies in England
and the United States, using criteria similar
to those in this manual, suggest that PDDNOS
is more common than Autistic Disorder in the
general population.
Qualitative impairment in
reciprocal social interaction.
This impairment is characterized by failure
to develop interpersonal relationships and by
lack of responsiveness to, or interest in,
people. In infancy these deficiencies may be
manifested by a failure to cuddle, by lack of
eye contact and facial responsiveness, and by
indifference or aversion to affection and
physical contact. As a result, parents often
suspect that the child is deaf (not realizing
that deafness, by itself, is rarely
associated with extreme social indifference).
Adults may be treated as interchangeable, or
the child may cling mechanically to a
specific person. The attachment of some
toddlers to their parent(s) may be bizarre,
e.g., a child may seem to recognize his
mother primarily on the basis of smell.
In some cases the disorder apparently follows
a period of normal, or relatively normal,
social development in the first years of
life; but even in early childhood, there is
invariably failure to develop cooperative
play, imaginative play, and friendships. As
the child grows older, however, greater
awareness of, and social interest in, others
may develop. Some of the least handicapped
may eventually reach a stage in which they
can become passively involved in other
children's games or physical play, or include
other children as "mechanical aids"
in their own stereotyped activities.
Impairment in communication and
imaginative activity.
Impairment in communication includes both
verbal and nonverbal skills. Language may be
totally absent. When it develops, it is often
characterized by: immature but essentially
normal grammatical structure; delayed or
immediate echolalia; pronoun reversals (e.g.,
use of "you" when -i- is intended);
inability to name objects; inability to use
abstract terms; idiosyncratic utterances
whose meaning is clear only to those who are
familiar with the child's past experiences
(termed metaphorical language by Kanner); and
abnormal speech melody, such as questionlike
rises at ends of statements or monotonous
tone of voice. Nonverbal communication, e.g.,
facial expression and gesture, is absent or
minimal or, if present, is socially
inappropriate in form.
Even when there are no gross abnormalities in
language skills, communication is often
impaired by circumstantially and
irrelevancies. A disturbance in the
comprehension of language may be evidenced by
an inability to understand jokes, puns, and
sarcasm.
Impairment in imaginative activity may
include absence symbolic or fantasy play with
toys or absence of playacting of adult roles,
or imaginative activity may be restricted in
content and repetitive and stereotyped in
form. This is in marked contrast to the
varied content of normal "pretend"
play. For example, a child with the disorder
may insist on lining up an exact number of
playthings in the same manner over and over
again, or repetitively mimic the actions of a
television character.
Markedly restricted
repertoire of activities and interests.
This restriction may take
various forms. In the younger child there may
be resistance or even catastrophic reactions
to minor changes in the environment, e.g.,
the child may scream when his or her place at
the dinner table is changed. There is often
attachment to objects such as a string or
rubber band. Motor stereotypes include
hand-clapping, peculiar hand movements,
rocking, and dipping and swaying movements of
the whole body. In the older child there may
be an insistence on following routines in a
precise way, e.g., taking the same route to a
favorite restaurant. There may be fascination
with movement, such as passively staring at
an electric fan or other rapidly revolving
object. The child himself may be skillful at
making all kinds of objects spin, so that he
can watch them, or may spin himself around.
The child may be exclusively interested in
buttons, parts of the body, or playing with
water.
Verbal stereotypes include repetition of
words or phrases regardless of meaning. In
older children, tasks involving long-term
memory, for example, recall of the exact
words of songs heard years before, train
timetables, historical dates, or chemical
formulae, may be excellent, but the
information tends to be repeated over and
over again, regardless of the social context
and the appropriateness of the information.
Associated features. In
general, the younger the child and the more
severe the handicaps, the more associated
features are likely to be present. They may
include the following;
- Abnormalities in the development of
cognitive skills. The profile of
specific skills is usually uneven,
regardless of general level of
intelligence. In most cases there is
an associated diagnosis of Mental
Retardation, most commonly in the
moderate range
- Abnormalities of posture and motor
behavior, such as stereotypes
(arm-flapping, jumping, grimacing) in
response to excitement, walking on
tiptoe, odd hand and body postures,
and poor motor coordination.
- Odd responses to sensory input, such
as ignoring some sensations (e.g.,
pain, heat, cold), displaying
oversensitivity to certain sensations
(e.g., covering ears to shut out some
sounds; dislike of being touched),
and being fascinated by some
sensations (e.g., exaggerated
reaction to lights or odors).
- Abnormalities in eating, drinking, or
sleeping (e.g., limiting diet to few
foods, excessive drinking of fluids,
recurrent awakening at night with
rocking).
- Abnormalities of mood (e.g., labile
mood, giggling or weeping for no
apparent reason, apparent absence of
emotional reactions, lack of fear of
real dangers, excessive fearfulness
in response to harmless objects or
events, generalized anxiety and
tension).
- Self-injurious behavior, such as
head-banging, or finger-, hand-, or
wrist-biting.
Other mental disorders, such as Major
Depression, may occur during adolescence and
adult life. They are most easily recognized
in people who have stifficient speech to
describe symptoms accurately.
Age at onset. Onset is
reported by parents to be before age three in
the great majority of cases. Very few cases
are reported with an onset after five or six.
However, it may be difficult to establish age
at onset retrospectively unless those who
cared for the child during the early years
are able to give accurate information about
language development, sociability, and play.
Manifestations in infancy are more subtle and
hard to define than those seen after two
years of age. Parents of only children may be
unaware of the problems until the child is
observed with other children (for example, on
entering school), and may then date the age
at onset from that point, although a careful
history often reveals that the abnormalities
were present earlier. Parents may also date
onset from a particular event, such as the
birth of a sibling, or from the time when the
child experienced a severe illness or
accident or emotional trauma. In such cases,
it is difficult to know whether subtle signs
of the disorder may not have been present
before the event.
In extremely rare cases, there is a period of
apparently normal development followed by
rapid disintegration of social and cognitive
skills and development of the characteristic
features of a Pervasive Developmental
Disorder. Such cases have been termed
Heller's syndrome or disintegrative
psychosis, but according to this manual,
should be classified as either Autistic
Disorder or Pervasive Developmental Disorder
Not Otherwise Specified.
Course. Manifestations of
the disorder are, in almost all cases,
lifelong, although they vary with
chronological age and severity of the
handicaps. Some children experience an
improvement in social, language, and other
skills at about age five to six years; in a
few cases, this may be very marked.
Puberty can bring changes in either
direction. Cognitive functions and social
skills may decline or improve independently
of each other. There is often an exacerbation
of aggressive, oppositional, or other
troublesome behavior, which may last for many
years. A small minority of the children
eventually are able to lead independent
lives, with only minimal signs of the
essential features of the disorder; but the
social awkwardness and ineptness may persist.
Most remain handicapped, with marked signs of
the disorder. Factors related to long-term
prognosis include IQ and the development of
social and language skills.
Degree of impairment. The
degree of impairment varies. In the majority
of cases, a structured environment is
necessary throughout life. In very rare
cases, the person may complete college or
even graduate education.
Complications. The major
complication is the development of epileptic
seizures. Most of those who develop seizures
have an IQ below 50. In about 25% or more of
cases of Autistic Disorder, there has been
one or more episodes of seizure by the time
the person reaches adulthood; in a sizable
minority, onset of seizures is in
adolescence.
In adolescence or early adult life,
depression in response to partial realization
of handicaps is common in those of higher
levels of ability Catatonic phenomena,
particularly excitement or posturing, or an
undifferentiated psychotic state with
apparent delusions and hallucinations can
occur in response to stress, but often clear
rapidly if the stress is removed.
Prevalence. Studies in
England and the United States, using criteria
similar to those in this manual, suggest that
the prevalence of Autistic Disorder is
approximately 4 to 5 children in every
10,000. Autistic Disorder was previously
thought to be more common in upper
socioeconomic classes, but studies suggest
that this finding was a function of referral
bias. The prevalence of Pervasive
Developmental Disorder (Autistic Disorder and
Pervasive Developmental Disorder Not
Otherwise Specified) has been estimated at 10
to 15 children in every 10,000.
Sex ratio. Pervasive
Developmental Disorder is more common among
males than females, studies showing ratios
ranging from 2:1 to 5:1
* Most studies of Autistic Disorder show a
ratio of 3:1 or 4:1.
Predisposing Factors. A
very wide range of pre-, peri- and postnatal
conditions causing brain dysfunction are
thought to predispose to the development of
Pervasive Developmental Disorders. Autistic
Disorder has been reported in association
with maternal rubella, untreated
phenylketonuria, tuberous sclerosis, anoxia
during birth, encephalitis, infantile spasms,
and fragile X syndrome. In the past, certain
abnormalities of parental personality and
child-rearing practices were thought to
predispose to the development of Autistic
Disorder, but controlled studies have not
confirmed this view.
Familial pattern.
Autistic Disorder is apparently more common
in the siblings of children with the disorder
than in the general population.
Differential diagnosis.
Mental Retardation and Pervasive
Developmental Disorder often coexist, but it
should be understood that most people with
even severe Mental Retardation do not have
the essential features of Pervasive
Developmental Disorder in that they are
sociable and can communicate-even nonverbally
if they have no speech. Differential
diagnosis in people with severe or profound
Mental Retardation may be difficult. When
interest and pleasure in social approaches
are evident, through eye contact, facial
expression, bodily movements, and
vocalizations, the diagnosis of Pervasive
Developmental Disorder should not be made.
Schizophrenia
The diagnosis of Schizophrenia is
extremely rare in childhood, whereas
Pervasive Developmental Disorder is almost
always first diagnosed in infancy or
childhood. As adults, people with Pervasive
Developmental Disorder may have many of the
"negative symptoms" of the residual
phase of Schizophrenia, such as social
isolation and withdrawal, markedly peculiar
behavior, blunted or inappropriate affect and
oddities of language. The stereotyped,
repetitive acting of a particular role-of an
object, animal, or individual by a person
with Pervasive Developmental Disorder may be
mistaken for a delusion. If the criteria for
Autistic Disorder are met, the additional
diagnosis of Schizophrenia should be made
only in the rare instances in which prominent
delusions or hallucinations meeting the
criteria for Schizophrenia can be documented.
Schizophrenia, however, preempts a diagnosis
of Pervasive Developmental Disorder Not
Otherwise Specified.
Hearing impairments and Specific
Developmental Language and Speech Disorders
affect the development of understanding
and/or use of speech. Some visual impairments
result in poor eye contact, and can be
associated with staring at repetitive hand
movements. Disorders involving only sensory
and perceptual impairment can be
differentiated from Pervasive Developmental
Disorder by the presence of social
interaction and a desire for communication
appropriate for the person's mental age.
In Schizoid and Schizotypal Personality
Disorders there are deficits in interpersonal
relatedness. The diagnosis of Autistic
Disorder preempts the diagnosis of these
personality disorders. However, these
personality disorders preempt the diagnosis
of Pervasive Developmental Disorder Not
Otherwise Specified.
In Tic Disorders and Stereotypy/Habit
Disorder there are stereotyped body
movements, but there is no qualitative
impairment in reciprocal social interaction.
Autistic
Disorder
The essential features constitute a severe
form of Pervasive Developmental Disorder,
with onset in infancy or childhood. The
other features of the disorder are described
on the previous page.
Diagnostic Criteria for Autistic
Disorder
At least eight of the following sixteen items
are present, these to include at least two
items from A, one from B, and one from C.
Note: Consider a criterion to be met only if
the behavior is abnormal for the person's
developmental level.
A. Qualitative impairment
in reciprocal social interaction as
manifested by the following:
(The examples within parentheses are arranged
so that those first mentioned are more likely
to apply to younger or more handicapped, and
the later ones, to older or less handicapped,
persons with this disorder.)
- marked lack of awareness of the
existence or feelings of others (e.g,
treats a person as if he or she were
a piece of furniture; does not notice
another person's distress; apparently
has no concept of the need of others
for privacy)
- no or abnormal seeking of comfort at
times of distress (e.g., does not
come for comfort even when ill, hurt,
or tired; seeks comfort in a
stereotyped way, e.g., says
"cheese, cheese, cheese"
whenever hurt)
- no or impaired imitation (e.g., does
not wave bye-bye; does not copy
mothers domestic activities;
mechanical imitation of others'
actions out of context)
- no or abnormal social play (e.g.,
does not actively participate in
simple games; prefers solitary play
activities; involves other children
in play only as "mechanical
aids")
- gross impairment in ability to make
peer friendships (e.g., no interest
in making peer friendships; despite
interest in making friends,
demonstrates lack of understanding of
conventions of social interaction,
for example, reads phone book to
uninterested peer)
B. Qualitative impairment
in verbal and nonverbal communication, and in
imaginative activity, as manifested by the
following:
(The numbered items are arranged so that
those first listed are more likely to apply
to younger or more handicapped, and the later
ones, to older or less handicapped, persons
with this disorder.)
- no mode of communication, such as
communicative babbling, facial
expression, gesture, mime, or spoken
language
- markedly abnormal nonverbal
communication, as in the use of
eye-to-eye gaze, facial expression,
body posture, or gestures to initiate
or modulate social interaction (e.g.,
does not anticipate being held,
stiffens when held, does not look at
the person or smile when making a
social approach, does not greet
parents or visitors, has a fixed
stare in social situations)
- absence of imaginative activity, such
as playacting of adult roles, fantasy
characters, or animals; lack of
interest in stories about imaginary
events
- marked abnormalities in the
production of speech, including
volume, pitch, stress, rate, rhythm,
and intonation (e.g., monotonous
tone, questionlike melody, or high
pitch)
- marked abnormalities in the form or
content of speech, including
stereotyped and repetitive use of
speech (e.g., immediate echolaha or
mechanical repetition of television
commercial); use of "you"
when "I" is meant (e.g.,
using "You want cookie?" to
mean I want a cookie");
idiosyncratic use of words or phrases
(e.g., "Go on green riding"
to mean "1 want to go on the
swing"); or frequent irrelevant
remarks (e.g., starts talking about
train schedules during a conversation
about sports)
- marked impairment in the ability to
initiate or sustain a conversation
with others, despite adequate speech
(e.g., indulging in lengthy
monologues on one subject regardless
of interjections from others)
C. Markedly restricted
repertoire of activities and interests, as
manifested by the following:
- stereotyped body movements, e.g.,
hand-flicking or -twisting, spinning,
head-banging, complex whole-body
movements
- persistent preoccupation with parts
of objects (e.g., sniffing or
smelling objects, repetitive feeling
of texture of materials, spinning
wheels of toy cars) or attachment to
unusual objects (e.g., insists on
carrying around a piece of string)
- marked distress over changes in
trivial aspects of environment, e.g.,
when a vase is moved from usual
position
- unreasonable insistence on following
routines in precise detail, e.g.,
insisting that exactly the same route
always be followed when shopping
- markedly restricted range of
interests and a preoccupation with
one narrow interest, e.g., interested
only in lining up objects, in
amassing facts about meteorology, or
in pretending to be a fantasy
character
D. Onset during infancy
or childhood.
Pervasive
Developmental Disorder
Not Otherwise Specified
This category should be used when there is
a qualitative impairment in the development
of reciprocal social interaction and of
verbal and nonverbal communication skills,
but the criteria are not met for Autistic
Disorder, Schizophrenia, or Schizotypal or
Schizoid Personality Disorder. Some people
with this diagnosis will exhibit a markedly
restricted repertoire of activities and
interests, but others will not.
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