PDD-NOS - Pervasive Developmental Disorder - Not Otherwise Specified

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 D.C., 1994, and is the main diagnostic reference of Mental Health professionals in the United States of America.

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 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 upon 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 PDD (like autism) or 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, 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 find 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 a child from obtaining services relative to their needs.
Also within each diagnosis is the Panel of Professional Advisors' recommended definition of the Autism Spectrum and related syndromes and conditions, which are not to be used for research purposes, but rather for defining the demographics of the membership of the Autism Society of America. The Autism Society of America 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-aspergers. 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.


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

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):

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)

Lack of social or emotional reciprocity

Qualitative impairments in communication as manifested by at least one of the following:
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)

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

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 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 object

B. Delays or abnormal functioning in at least one of the following areas, with onset prior to age 3 years:

Social interaction

Language as used in social communication

Symbolic or imaginative play

C. The disturbance is not better accounted for by Rett's Disorder or Childhood Disintegrative Disorder.

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 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.

A.  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

B. 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 handwashing)

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


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.

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.

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:
Expressive or receptive language
Social skills or adaptive behavior
Bowel or bladder control
Play
Motor skills

C. 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

D. The disturbance is not better accounted for by another specific Pervasive Developmental Disorder or by Schizophrenia.

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

Cornelia DeLange Syndrome

Cornelia DeLange Syndrome is a relatively rare syndrome associated with autism. Individuals with this syndrome have low birth weight, delayed growth, small stature, small head size, and distinctive facial features including the eyebrows (which usually meet at the midline), long eyelashes, short up-turned nose, and thin down-turned lips. Individuals with Cornelia DeLange Syndrome have developmental delays with the greatest area being in receptive and expressive language. Additionally, they have heightened sensitivity to touch, present behavioral difficulties including hyperactivity, short attention span, oppositional and repetitive behavior, and self-injurious behavior. Because these behavioral characteristics are similar in many ways to those present in individuals with autism, "autistic-like behaviors" are listed as an associated complication for individuals with Cornelia DeLange Syndrome. (Cornelia DeLange Syndrome Foundation, 1998)

Tourette's Syndrome

Tourette's Syndrome is an inherited neurological disorder characterized by repeated and involuntary body movements (tics) and uncontrollable vocal sounds. In a minority of cases, the vocalizations can include socially inappropriate words and phrases (coprolalia). Involuntary symptoms can include eye blinking, repeated throat clearing or sniffing, arm thrusting, kicking movements, shoulder shrugging, or jumping. Stereotyped motor movements, verbal stereotypes, such as, the repetition of words and phrases, and other mannerisms have suggested a potentially more interesting association between autism and Tourette's Syndrome. (Tourette's Syndrome Association, 1998)

Fragile X Syndrome

Early descriptions of Fragile X Syndrome focused on fully affected males and their many autistic-like features. These included: poor eye contact; language delay; perseveration and echolalia; self-abuse; behavioral stereotypes (hand flapping, body rocking); sensitivity to auditory stimuli or environmental change; tactile defensiveness; preoccupation with narrow range of stimuli; and poor social relating. Prevalence rates for Fragile X Syndrome amongst individuals with autism is approximately 10 percent. (Dykens & Volkmar, 1997, pp 390+)

William's Syndrome

William's Syndrome affects about 1 in 20,000 people and is caused, in most cases, by a deletion in one of the chromosomes 7s that contain the gene for elastin. People with autism with William Syndrome often show a distinctive cognitive profile. Relations between William Syndrome and autism have not yet been widely studied; however, some of the maladaptive behaviors of William Syndrome may be described as "autistic-like." These include obsessive worrying, perseveration, difficulties relating to peers, and body rocking and other repetitive behaviors. (Dykens & Volkmar, 1997, pp393+)

Down Syndrome

Down Syndrome occurs in approximately 1 in 800 births and is considered the most common chromosomal cause of retardation. Although rare, some epidemiological studies have found subjects with Down Syndrome and autism. Although autism is rare in persons with Down Syndrome, it should be considered in the range of diagnostic possibilities for persons with this syndrome. (Dykens & Volkmar, 1997, pp 394+) When autism affects a child with Down Syndrome the effects are quite severe, and, therefore, the autism condition must be the priority condition.

Tuberous Sclerosis

Tuberous Sclerosis affects as many as 1 in 10,000 people and is characterized by abnormal tissue growth or benign tumors in the brain and other organs such as the skin, kidneys, eyes, heart, and lungs. Autistic-like symptoms were first described in patients with Tuberous Sclerosis a decade before Kanner's classic delineation of Infantile Autism. These early noted symptoms include stereotypes, absents or abnormal speech, withdrawal, and impaired interactions. Today the Tuberous Sclerosis society suggests that approximately 60 percent of its membership have autism or autistic-like behavior or symptoms. (Bassiri, 1998, Personal Correspondence) (Dykens & Volkmar, 1997, pp 395+)

Landau-Kleffner Syndrome

This syndrome has its onset in childhood and is characterized by acquired aphasia and seizures in association with abnormal EEG's. Landau-Kleffner Syndrome, often referred to as "acquired epileptic aphasia," may present autistic symptomatology. However, the primary symptom is represented by language regression. (Minshew Sweeney, & Bauman, 1997, pp 361+)

Sensory Impairments

Visually and auditory impaired individuals may also have autism.
Additionally, Kluver- Bucy Syndrome (Ivey M. et. al, 1989) has symptoms similar to autism such as difficulty in receiving and processing sensory information.

Defining Symptomatology

Occasionally with autism there are certain symptoms that become defining of the individual as he/she ages. It is critical not to confuse the evolving, defining symptom as primary in nature, but rather secondary to the syndrome of autism itself. Those symptomatologies are obsessive /compulsive disorder; bipolar disorder, depressions; anxiety disorder; epilepsy; and attention-deficit/hyperactivity disorder.

Disorders of Metabolism/Infections

Other forms of metabolic disorders may have autistic-like symptomatology. These include Prader-Willi Syndrome, PKU (phenylketonuria), and Lesch-Nyhan Syndrome to name a few. Additionally, there is a theory that identifies Candida yeast infection as a culpable agent in autism. (Rimland, 1988) The majority of cases of autism however, are of unknown origin. DLH: 1999

www.nichd.nih.gov/health/topics/fragile_x_syndrome.cfm

Down Syndrome

www1.ndss.org

www.kidshealth.org/kid/health_problems/birth_defect/down_syndrome.html

Tourette's Syndrome

www.tsa-usa.org

www.ninds.nih.gov/disorders/tourette/detail_tourette.htm

www.kidshealth.org/parent/medical/brain/tourette.htm

www.tourettes-disorder.com

ghr.nlm.nih.gov/condition=corneliadelangesyndrome

www.ucdmc.ucdavis.edu/children/services/cleft/health/anomalies/cornelia.html

Landau-Kleffner Syndrome

nidcd.nih.gov/health/voice/landklfs.htm

www.autism.org/landau.html

Williams Syndrome

www.ninds.nih.gov/disorders/williams/williams

International Rett Syndrome Association
9121 Piscataway Road, Suite 2B
Clinton, MD 20735
(301) 856-3334
(800) 818-7388
www.rettsyndrome.org

Rett Syndrome Research Foundation
4600 Devitt Drive
Cincinnati, OH 45246
(513) 874-3020
www.rsrf.org

Easter Seals
230 W. Monroe Street, Suite 1800
Chicago, IL 60606-4802
(312) 762-6200
(800) 221-6827
www.easter-seals.org

National Institute of Child Health and Human Development
Building 31, Room 2A32
Bethesda, MD 20892-2425
(301) 496-5133
www.nichd.nih.gov