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Definition of the PDD Category
and its Five Specific Disorders
All types of PDD are neurological disorders that are usually
evident by age 3. In general, children who have a type of PDD have
difficulty in talking, playing with other children, and relating to
others, including their family.
According to the definition set forth in the DSM-IV (American
Psychiatric Association, 1994), Pervasive Developmental Disorders are
characterized by severe and pervasive impairment in several areas of
development:
social interaction skills;
communication skills; or
the presence of stereotyped behavior, interests, and activities.
Information on the
Five Specific Disorders in the PDD Category
For more information
on Autism, click here.
For more information
on Asperger's Syndrome, click here.
For more information
on Rett's Syndrome, click here.
For more information
on Childhood Disintegrative Disorder,
click here.
For more information
on PDD-NOS, see below.
The Five Types of PDD
(1) Autistic Disorder. Autistic Disorder, sometimes referred to as
early infantile autism or childhood autism, is four times more common
in boys than in girls. Children with Autistic Disorder have a moderate
to severe range of communication, socialization, and behavior
problems. Many children with autism also have mental retardation. The
DSM-IV criteria by which Autistic Disorder is diagnosed are presented
below.
Diagnostic Criteria for Autistic Disorder
A. A total of six (or more) items from (1), (2), and (3), with at
least two from (1), and one each from (2) and (3):
(1) qualitative impairment in social interaction, as manifested by at
least two of the following:
(a) marked impairment in the use of multiple nonverbal behaviors such
as eye-to-eye gaze, facial expression, body postures, and gestures to
regulate social interaction
(b) failure to develop peer relationships appropriate to developmental
level
(c) a lack of spontaneous seeking to share enjoyment, interests, or
achievements with other people (e.g., by a lack of showing, bringing,
or pointing out objects of interest)
(d) lack of social or emotional reciprocity
(2) qualitative impairments in communication as manifested by at least
one of the following:
(a) delay in, or total lack of, the development of spoken language
(not accompanied by an attempt to compensate through alternative modes
of communication such as gesture or mime)
(b) in individuals with adequate speech, marked impairment in the
ability to initiate or sustain a conversation with others
(c) stereotyped and repetitive use of language or idiosyncratic
language
(d) lack of varied, spontaneous make-believe play or social imitative
play appropriate to developmental level
(3) restricted repetitive and stereotyped patterns of behavior,
interests, and activities, as manifested by at least one of the
following:
(a) encompassing preoccupation with one or more stereotyped and
restricted patterns of interest that is abnormal either in intensity
or focus
(b) apparently inflexible adherence to specific, nonfunctional
routines or rituals
(c) stereotyped and repetitive motor mannerisms (e.g., hand or finger
flapping or twisting, or complex whole-body movements)
(d) persistent preoccupation with parts of objects
B. Delays or abnormal functioning in at least one of the following
areas, with onset prior to age 3 years: (1) social interaction, (2)
language as used in social communication, or (3) symbolic or
imaginative play.
C. The disturbance is not better accounted for by Rett's Disorder or
Childhood Disintegrative Disorder. (APA, 1994, pp. 70-71)
(Reprinted with permission from the Diagnostic and Statistical Manual
of Mental Disorders, Fourth Edition. Copyright 1994 American
Psychiatric Association.)
(2) Rett's Disorder. Rett's Disorder, also known as Rett Syndrome, is
diagnosed primarily in females. In children with Rett's Disorder,
development proceeds in an apparently normal fashion over the first 6
to 18 months at which point parents notice a change in their child's
behavior and some regression or loss of abilities, especially in gross
motor skills such as walking and moving. This is followed by an
obvious loss in abilities such as speech, reasoning, and hand use. The
repetition of certain meaningless gestures or movements is an
important clue to diagnosing Rett's Disorder; these gestures typically
consist of constant hand-wringing or hand-washing (Moeschler, Gibbs, &
Graham 1990). The diagnostic criteria for Rett's Disorder as set forth
in the DSM-IV appear below.
Diagnostic Criteria for Rett's Disorder
A. All of the following:
(1) apparently normal prenatal and perinatal development
(2) apparently normal psychomotor development through the first 5
months after birth
(3) normal head circumference at birth
B. Onset of all of the following after the period of normal
development
(1) deceleration of head growth between ages 5 and 48 months
(2) loss of previously acquired purposeful hand skills between ages 5
and 30 months with the subsequent development of stereotyped hand
movements (e.g., hand-wringing or hand washing)
(3) loss of social engagement early in the course (although often
social interaction develops later)
(4) appearance of poorly coordinated gait or trunk movements
(5) severely impaired expressive and receptive language development
with severe psychomotor retardation. (APA, 1994, pp. 72-73)
(Reprinted with permission from the Diagnostic and Statistical Manual
of Mental Disorders, Fourth Edition. Copyright 1994 American
Psychiatric Association.)
(3) Childhood Disintegrative Disorder. Childhood Disintegrative
Disorder, an extremely rare disorder, is a clearly apparent regression
in multiple areas of functioning (such as the ability to move, bladder
and bowel control, and social and language skills) following a period
of at least 2 years of apparently normal development. By definition,
Childhood Disintegrative Disorder can only be diagnosed if the
symptoms are preceded by at least 2 years of normal development and
the onset of decline is prior to age 10 (American Psychiatric
Association, 1994). DSM-IV criteria are presented below.
Diagnostic Criteria for Childhood Disintegrative Disorder
A. Apparently normal development for at least the first 2 years after
birth as manifested by the presence of age-appropriate verbal and
nonverbal communication, social relationships, play, and adaptive
behavior.
B. Clinically significant loss of previously acquired skills (before
age 10 years) in at least two of the following areas:
(1) expressive or receptive language
(2) social skills or adaptive behavior
(3) bowel or bladder control
(4) play
(5) motor skills
C. Abnormalities of functioning in at least two of the following
areas:
(1) qualitative impairment in social interaction (e.g., impairment in
nonverbal behaviors, failure to develop peer relationships, lack of
social or emotional reciprocity)
(2) qualitative impairments in communication (e.g., delay or lack of
spoken language, inability to initiate or sustain a conversation,
stereotyped and repetitive use of language, lack of varied
make-believe play)
(3) restricted, repetitive, and stereotyped patterns of behavior,
interests, and activities, including motor stereotypes and mannerisms
D. The disturbance is not better accounted for by another specific
Pervasive Developmental Disorder or by Schizophrenia. (APA, 1994, pp.
74-75)
(Reprinted with permission from the Diagnostic and Statistical Manual
of Mental Disorders, Fourth Edition. Copyright 1994 American
Psychiatric Association.)
(4) Asperger's Disorder. Asperger's Disorder, also referred to as
Asperger's or Asperger's Syndrome, is a developmental disorder
characterized by a lack of social skills; difficulty with social
relationships; poor coordination and poor concentration; and a
restricted range of interests, but normal intelligence and adequate
language skills in the areas of vocabulary and grammar. Asperger's
Disorder appears to have a somewhat later onset than Autistic
Disorder, or at least is recognized later. An individual with
Asperger's Disorder does not possess a significant delay in language
development; however, he or she may have difficulty understanding the
subtleties used in conversation, such as irony and humor. Also, while
many individuals with autism have mental retardation, a person with
Asperger's possesses an average to above average intelligence (Autism
Society of America, 1995). Asperger's is sometimes incorrectly
referred to as "high-functioning autism." The diagnostic criteria for
Asperger's Disorder as set forth in the DSM-IV are presented below.
Diagnostic Criteria for Asperger's Disorder
A. Qualitative impairment in social interaction, as manifested by at
least two of the following:
(1) marked impairment in the use of multiple nonverbal behaviors such
as eye-to-eye gaze, facial expression, body postures, and gestures to
regulate social interaction
(2) failure to develop peer relationships appropriate to developmental
level
(3) a lack of spontaneous seeking to share enjoyment, interests, or
achievements with other people (e.g., by a lack of showing, bringing,
or pointing out objects of interest)
(4) lack of social or emotional reciprocity
B. Restricted repetitive and stereotyped patterns of behavior,
interests, and activities, as manifested by at least one of the
following:
(1) encompassing preoccupation with one or more stereotyped and
restricted patterns of interest that is abnormal either in intensity
or focus
(2) apparently inflexible adherence to specific, nonfunctional
routines or rituals
(3) stereotyped and repetitive motor mannerisms (e.g., hand or finger
flapping or twisting, or complex whole-body movements)
(4) persistent preoccupation with parts of objects
C. The disturbance causes clinically significant impairment in social,
occupational, or other important areas of functioning.
D. There is no clinically significant general delay in language (e.g.,
single word used by age 2 years, communicative phrases used by age 3
years).
E. There is no clinically significant delay in cognitive development
or in the development of age-appropriate self-help skills, adaptive
behavior (other than in social interaction), and curiosity about the
environment in childhood.
F. Criteria are not met for another specific Pervasive Developmental
Disorder, or Schizophrenia. (APA, 1994, p. 77)
(Reprinted with permission from the Diagnostic and Statistical Manual
of Mental Disorders, Fourth Edition. Copyright 1994 American
Psychiatric Association.)
(5) Pervasive Developmental Disorder Not Otherwise Specified.
Children with PDDNOS either (a) do not fully meet the criteria of
symptoms clinicians use to diagnose any of the four specific types of
PDD above, and/or (b) do not have the degree of impairment described
in any of the above four PDD specific types.
According to the DSM-IV, this category should be used "when there is a
severe and pervasive impairment in the development of social
interaction or verbal and nonverbal communication skills, or when
stereotyped behavior, interests, and activities are present, but the
criteria are not met for a specific Pervasive Developmental Disorder,
Schizophrenia, Schizotypal Personality Disorder, or Avoidant
Personality Disorder" (American Psychiatric Association, 1994, pp.
77-78).
The Confusion of Diagnostic Labels
The intent behind the DSM-IV is that the diagnostic criteria not
be used as a checklist but, rather, as guidelines for diagnosing
pervasive developmental disorders. There are no clearly established
guidelines for measuring the severity of a person's symptoms.
Therefore, the line between autism and PDDNOS is blurry (Boyle, 1995).
As discussed earlier, there is still some disagreement among
professionals concerning the PDDNOS label. Some professionals consider
"Autistic Disorder" appropriate only for those who show extreme
symptoms in every one of several developmental areas related to
autism. Other professionals are more comfortable with the term
Autistic Disorder and use it to cover a broad range of symptoms
connected with language and social dysfunction. Therefore, an
individual may be diagnosed by one practitioner as having Autistic
Disorder and by another practitioner as having PDDNOS (or PDD, if the
practitioner is abbreviating for PDDNOS).
Generally, an individual is diagnosed as having PDDNOS if he or she
has some behaviors that are seen in autism but does not meet the full
DSM-IV criteria for having Autistic Disorder. Despite the DSM-IV
concept of Autistic Disorder and PDDNOS being two distinct types of
PDD, there is clinical evidence suggesting that Autistic Disorder and
PDDNOS are on a continuum (i.e., an individual with Autistic Disorder
can improve and be rediagnosed as having PDDNOS, or a young child can
begin with PDDNOS, develop more autistic features, and be rediagnosed
as having Autistic Disorder).
To add to the list of labels that parents, teachers, and others may
encounter, a new classification system was recently developed by ZERO
TO THREE: National Center for Infants, Toddlers, and Families (1994).
Under this system, called the Diagnostic Classification of Mental
Health and Developmental Disorders of Infancy and Early Childhood, the
term Multisystem Developmental Disorder, or MSDD, is used to describe
pervasive developmental disorders.
However, amidst all this confusion, it is very important to remember
that, regardless of whether a child's diagnostic label is autism,
PDDNOS, or MSDD, his or her treatment is similar.
For more information,
visit
http://www.nichcy.org/pubs/factshe/fs1txt.htm.
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