DSM-IV – Diagnostic Classifications

Pervasive Development Disorders (PDD)

The term “PDD” is widely used by professionals to refer to children with autism and related disorders; however, there is a great deal of disagreement and confusion among professionals concerning the PDD label. Diagnosis of PDD, including autism or any other developmental disability, is based upon the Diagnostic and Statistical Manual of Mental Disorders – Fourth Edition (DSM-IV), published by the American Psychiatric Association (Washington, DC, 1994), and is the main diagnostic reference of mental health professionals in the U.S.

According to the DSM-IV, the term “PDD” is not a specific diagnosis, but an umbrella term under which the specific diagnoses are defined.

Diagnostic labels are used to indicate commonalities among individuals. The key defining symptom of autism that differentiates it from other syndromes and/or conditions is substantial impairment in social interaction (Frith, 1989). The diagnosis of autism indicates that qualitative impairments in communication, social skills, and a range of interests and activities exist. As no medical tests can be performed to indicate the presence of autism or any other PDD, the diagnosis is based on the presence or absence of specific behaviors. For example, a child may be diagnosed as having PDD-NOS if he or she has some behaviors that are seen in autism, but does not meet the full criteria for having autism. Most importantly, whether a child is diagnosed with a PDD (like autism) or a PDD-NOS, his/her treatment will be similar.

Autism is a spectrum disorder, with symptoms ranging from mild to severe. As a spectrum disorder, the level of developmental delay is unique to each individual. If a diagnosis of PDD-NOS is made, rather than autism, the diagnosticians should clearly specify the behaviors present. Evaluation reports are more useful if they are specific and become more helpful for parents and professionals in later years when reevaluations are conducted.

Ideally, a multidisciplinary team of professionals should evaluate a child suspected of having autism. The team may include, but may not be limited to, a psychologist or psychiatrist, a speech pathologist, and other medical professionals, including a developmental pediatrician and/or neurologist. Parents and teachers should also be included, as they have important information to share when determining a child’s diagnosis.

In the end, parents should be more concerned that their child finds the appropriate educational treatment based on their needs, rather than spending too much effort to find the perfect diagnostic label. Most often, programs designed specifically for children with autism will produce greater benefits, while the use of the general PDD label can prevent children from obtaining services relative to their needs.

Also within each diagnosis is the Autism Society’s Panel of Professional Advisors’ recommended definition of the autism spectrum and related syndromes and conditions, which is not to be used for research purposes but rather for defining the demographics of the Autism Society’s membership. The Autism Society is not attempting to represent individuals with related syndromes or conditions who do not also have autism, but rather those where autism is present in related syndromes and conditions, and where autism is the defining syndrome (e.g., autism-Asperger’s). The rationale for this position is due to the unique service needs that are imperative for individuals with autism that may not be required of the cohort disability.

• Autistic Disorder (299.00 DSM-IV)
• Asperger’s Disorder (299.80 DSM-IV)
• Rett’s Disorder (299.80 DSM-IV)
• Childhood Disintegrative Disorder (299.10 DSM-IV)
• PDD-NOS (299.80 DSM-IV)

Autistic Disorder (299.00 DSM-IV)

The central features of Autistic Disorder are the presence of markedly abnormal or impaired development in social interaction and communication and a markedly restricted repertoire of activity and interest. The manifestations of this disorder vary greatly depending on the developmental level and chronological age of the individual. Autistic Disorder is sometimes referred to as Early Infantile Autism, Childhood Autism, or Kanner’s Autism (page 66).

1. 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):
2. Qualitative impairment in social interaction, as manifested by at least two of the following:
3. 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.
   • Failure to develop peer relationships appropriate to developmental level
   • 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)
   • Lack of social or emotional reciprocity
4. Qualitative impairments in communication as manifested by at least one of the following:
5. 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 gestures or mime)
6. • In individuals with adequate speech, marked impairment in the ability to initiate or sustain a conversation with others
   • Stereotyped and repetitive use of language or idiosyncratic language
   • Lack of varied, spontaneous make-believe play or social imitative play appropriate to developmental level
7. Restricted repetitive and stereotyped patterns of behavior, interests, and activities, as manifested by at least one of the following:
8. • Encompassing preoccupation with one or more stereotyped patterns of interest that is abnormal either in intensity or focus
   • Apparently inflexible adherence to specific, nonfunctional routines or rituals
   • Stereotyped and repetitive motor mannerisms (e.g., hand or finger flapping or twisting, or complex whole-body movements)
   • Persistent preoccupation with parts of an object
9. Delays or abnormal functioning in at least one of the following areas, with onset prior to age 3 years:
10. • Social interaction
    • Language as used in social communication
    • Symbolic or imaginative play
11. The disturbance is not better accounted for by Rett’s Disorder or Childhood Disintegrative Disorder.

Asperger’s Disorder (299.80 DSM-IV)

The essential features of Asperger’s Disorder are severe and sustained impairment in social interaction and the development of restricted, repetitive patterns of behavior, interest, and activity. The disturbance must clinically show significant impairment in social, occupational, and other important areas of functioning. In contrast to Autistic Disorder, there are no clinically significant delays in language. In addition, there are no clinically significant delays in cognitive development or in the development of age-appropriate self-help skills, adaptive behavior, and curiosity about the environment in childhood.

1. Qualitative impairment in social interaction, as manifested by at least two of the following:
   • 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
   • Failure to develop peer relationships appropriate to developmental level
   • 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 to other people)
   • Lack of social or emotional reciprocity
2. Restricted repetitive and stereotyped patterns of behavior, interests, and activities, as manifested by at least one of the following:
   • Encompassing preoccupation with one or more stereotyped and restricted patterns of interest that is abnormal either in intensity or focus
   • Apparently inflexible adherence to specific, non-functional routines or rituals
   • Stereotyped and repetitive motor mannerisms (e.g., hand or finger flapping or twisting, or complex whole-body movements)
   • Persistent preoccupation with parts of objects
3. The disturbance causes clinically significant impairment in social, occupational, or other important areas of functioning.
4. There is no clinically significant general delay in language (e.g., single words used by age 2 years, communicative phrases used by age 3 years)
5. 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.
6. Criteria are not met for another specific Pervasive Developmental Disorder or Schizophrenia.

Rett’s Disorder (299.80 DSM-IV)

The essential feature of Rett’s Disorder is the development of multiple specific deficits following a period of normal functioning after birth. There is a loss of previously acquired purposeful hand skills before the subsequent development of characteristic hand movement resembling hand wringing or hand washing. Interest in the social environment diminishes in the first few years after the onset of the disorder. There is also significant impairment in expressive and receptive language development with severe psychomotor retardation. (Page 71)

1. All of the following:
   • Apparently normal prenatal and prenatal development
   • Apparently normal psychomotor development through the first 5 months after birth
   • Normal head circumference at birth
2. Onset of all of the following after the period of normal development:
   • Deceleration of head growth between ages 5 and 48 months
   • 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)
   • Loss of social engagement early in the course (although often social interaction develops later)
   • Appearance of poorly coordinated gait or trunk movements
   • Severely impaired expressive and receptive language development with severe psychomotor retardation

Childhood Disintegrative Disorder (299.10 DSM-IV)

The central feature of Childhood Disintegrative Disorder is a marked regression in multiple areas of functioning following a period of at least two years of apparently normal development. After the first two years of life, the child has a clinically significant loss of previously acquired skills in at least two of the following areas: expressive or receptive language; social skills or adaptive behavior; bowel or bladder control; or play or motor skills. Individuals with this disorder exhibit the social and communicative deficits and behavioral features generally observed in Autistic Disorder, as there is qualitative impairment in social interaction, communication, and restrictive, repetitive, and stereotyped patterns of behavior, interests, and activities. (Page 73)

1. Apparently normal development for at least the first 2 years after birth is manifested by the presence of age-appropriate verbal and nonverbal communication, social relationships, play, and adaptive behavior.
2. Clinically significant loss of previously acquired skills (before age 10 years) in at least two of the following areas:
   • Expressive or receptive language
   • Social skills or adaptive behavior
   • Bowel or bladder control
   • Play
   • Motor skills
3. Abnormalities of functioning in at least two of the following areas:
   • Qualitative impairment in social interaction (e.g., impairment in nonverbal behaviors, failure to develop peer relationships, lack of social or emotional reciprocity)
   • 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)
   • Restricted, repetitive, and stereotyped patterns of behavior, interests, and activities, including motor stereotypes and mannerisms
4. The disturbance is not better accounted for by another specific Pervasive Developmental Disorder or by Schizophrenia.

PDD-NOS (299.80 DSM-IV)

The essential features of PDD-NOS are severe and pervasive impairment in the development of reciprocal social interaction or verbal and nonverbal communication skills; and stereotyped behaviors, interests, and activities. The criteria for Autistic Disorder are not met because of late age onset; atypical and/or sub-threshold symptomatology is present. (Pages 77-78)

This category should be used when there is a severe and pervasive impairment in the development of reciprocal 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, Schizotypical Personality Disorder, or Avoidant Personality Disorder. For example, this category includes “atypical autism“– presentations that do not meet the criteria for Autistic Disorder because of late age of onset, atypical symptomatology, sub-threshold symptomatology, or all of these.