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Pervasive Developmental Disorder
Article Last Updated: Mar 26, 2008
AUTHOR AND EDITOR INFORMATION
Section 1 of 12  
Author: Sufen Chiu, MD, PhD, Assistant Clinical Professor (Volunteer Faculty), University of California Davis Medical School; Consulting Staff, Child and Adolescent Psychiatry of Sacramento County; Consulting Staff, Sutter Center for Psychiatry; Consulting Staff, Transcultural Wellness Center
Sufen Chiu is a member of the following medical societies: American Academy of Child and Adolescent Psychiatry, American Academy of Pediatrics, American Psychiatric Association, California Medical Association, and Sierra Sacramento Valley Medical Society
Coauthor(s):
Randi Jenssen Hagerman, MD, FAAP, Professor of Pediatrics, Medical Director MIND Institute, Endowed Chair in Fragile X Research, Division of Developmental/Behavioral Pediatrics, University of California Davis Medical Center;
Henrietta Leonard, MD, Program Director, Child and Adolescent Psychiatry, Professor of Psychiatry and Human Development, Division of Child and Adolescent Psychiatry, Rhode Island Hospital and Brown University
Editors: Carol Diane Berkowitz, MD, Executive Vice Chair, Department of Pediatrics, Professor, Harbor-University of California at Los Angeles Medical Center; Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine.com, Inc; Carrie Sylvester, MD, MPH, Director of Education in Child and Adolescent Psychiatry, Professor, Departments of Psychiatry and Pediatrics, Northwestern University Medical School; Caroly Pataki, MD, Professor of Clinical Psychiatry, Department of Psychiatry and Biobehavioral Sciences, Division Chair of Child and Adolescent Psychiatry, Director of Training, Child and Adolescent Psychiatry Residency Program, University of Southern California Keck School of Medicine
Author and Editor Disclosure
Synonyms and related keywords:
personality developmental disorder, PDD, autistic disorder, autism, Rett disorder, Rett syndrome, childhood disintegrative disorder, Asperger disorder, Asperger syndrome, pervasive developmental disorder not otherwise specified, childhood disintegration, obsessive compulsive disorder, OCD, attention deficit hyperactivity disorder, ADHD, schizophrenia, anxiety, regression, language delay, epilepsy, cerebral palsy, tuberous sclerosis, phenylketonuria, neurofibromatosis, Down syndrome, congenital rubella
Background
Pervasive developmental disorders (PDDs) include a spectrum of behavioral problems commonly associated with autism. The Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) includes autism, Rett syndrome, childhood disintegration, Asperger syndrome, and PDD not otherwise specified under the spectrum of PDD.1 These individual disorders are discussed briefly in this article. For detailed reviews of each, see the eMedicine articles listed above. The most notable behavioral problems arise in social interaction and communication. Other problematic areas include stereotyped behaviors, restrictive interests or activities, and cognitive deficits. Autistic disorder in its most severe presentation may describe a child aged 3 years who presents with no expressive language, seeking comfort from parents in atypical ways, with pervasive hand flapping, no eye contact, and battles over toilet training. In the mildest presentation, PDD not otherwise specified may be used to describe a child aged 9 years with poor peer interactions and normal verbal and nonverbal intelligence. This child's preoccupation with one of a few restricted interests even tires the patience of typically developing peers with similar interests.
Pathophysiology
The underlying pathophysiology of PDD is under investigation. Current research implicates several CNS systems at different levels. For example, at the molecular level, the type of serotonin-transporter gene promoter may modulate the severity of PDD. Recent data suggest a role for immune system. At the neuroanatomic level, preliminary brain imaging studies have shown differences.2 No single anomaly has been demonstrated reliably because of differences between studies related to intelligence quotient (IQ), medication exposure, age of the patient sample, and methods for case ascertainment (low vs high functioning, autistic disorder vs Asperger disorder). Children with PDD may have other specific cognitive deficits, including central auditory processing problems, which imply distorted pathways between hearing and cortical processing. They may also have specific cognitive strengths. In isolated cases, these special cognitive talents lead to these individuals being labeled savants.
Frequency
United States
A survey of existing literature by Fombonne in 2003 indicated that the current rates for PDD are 30-60 cases per 10,000 population for all forms of PDD, 2.5 cases for 10,000 population for Asperger disorder, and 0.2 case per 10,000 population for childhood disintegrative disorder.3 Fombonne attributes the increase in prevalences over time to changes in case definitions and to improved awareness. Available surveys lack sufficient proof to support an increase in the prevalence of PDD for other reasons.
International
No evidence suggests that international prevalence of the disease differs from prevalence in the United States.
Mortality/Morbidity
- Obsessive-compulsive disorder (OCD) and attention deficit hyperactivity disorder (ADHD) are often comorbid psychiatric symptoms that some clinicians label separately, whereas others include them as part of the presentation of PDD. Regardless of the approach, these symptoms of OCD and ADHD may be disabling and require treatment with standard approaches that include but that are not limited to medications and behavioral therapy.
- Aggression is a symptom not specific to any particular psychiatric disorder. The etiologies are broad and include constipation, depression, anxiety, psychosis, or adjustment disorder. Treatment requires clarification of etiology to help select medications and other appropriate therapies.
- Psychosis is often the most difficult symptom to elicit and diagnose appropriately in children with PDD. Not long ago, children with PDD were often identified as having childhood-onset schizophrenia. The DSM establishes criteria that clearly distinguish PDD from childhood-onset schizophrenia. The DSM recognizes that children with PDD may develop psychotic disorders if they present with clear evidence of auditory, visual, tactile, and/or olfactory hallucinations. Nevertheless, determining whether a child has PDD or psychosis may be difficult during the initial clinical evaluation. For example, individuals with mental retardation may present with cognitive disorganization; they may link irrelevant thoughts together or have beliefs in magical beings, even as adults. These findings are considered normal in a person with intellectual disability.
Race
Race has not been implicated as a risk factor for PDD.
Sex
Sex bias for PDD is significant.
- Autism and PDD not otherwise specified may affect boys up to 5 times more often than girls.
- In Asperger syndrome, boys may be affected 10 times more often than girls.
- Only in Rett syndrome are girls more commonly affected than boys; Rett syndrome is rarely diagnosed in boys. However, new molecular testing for Rett syndrome is identifying more affected boys than previously reported.
Age
Autistic disorder carries an onset criterion; evidence of the disorder must be present by age 3 years. Rett syndrome and childhood disintegrative disorder are also usually apparent by age 3 years. Regression, or the loss of developmental milestones, remains controversial in autistic disorder. The loss of developmental milestones traditionally suggested Rett syndrome or childhood disintegrative disorder. However, growing evidence suggests that regression may be an important subtype of autistic disorder.
History
Reactive attachment disorder is an important differential diagnostic entity for pervasive developmental disorder (PDD). If any child has a clinically significant history of physical or emotional deprivation, a PDD diagnosis should be deferred until the child has had an opportunity to recover in an enriched environment. Any history of deficiencies in the following areas is an indication for an evaluation for PDD.
- Language development
- Delay - Suggests autism or PDD not otherwise specified
- Regression4 - Consistent with Rett disorder or childhood disintegrative disorder but may also be an important subtype of autistic disorder
- Normal language development - Diagnostic feature of Asperger disorder
- Poor social interaction
- Social isolation
- Poor eye contact
- Attachment to unusual objects
- Overdeveloped circumscribed interests in odd or specific topics
- Inability to engage in imaginative play
- Stereotyped behaviors
- Hand flapping
- Self-injurious behavior (eg, head banging)
- Difficulty making a transition between activities
- Sensory integration difficulties
- Oral aversion to certain textures or colors
- Olfactory aversion
- Tactile aversion to certain fabrics (eg, tags on clothing, position of socks)
- Auditory aversion to loud noises or types of music
The social communication questionnaire (SCQ) is a short parent report of current and past behavior. It has been validated to be consistent with the Autism Diagnostic Observation Schedule (ADOS) and has excellent sensitivity and specificity for PDDs.5 The form is filled out by parents and is short enough to be completed in the waiting room.
Physical
Physical examination findings are usually normal, but the evaluation should be thorough to exclude genetic or metabolic disorders.6 Children with PDD often have no physical findings. The most important exception is Rett disorder; almost all patients who present with this disorder have the characteristic findings of hand-wringing, hyperventilation, or both.
Causes
Identified organic disorders that occur with PDD include epilepsy (the most common medical condition associated with PDD), cerebral palsy, fragile X syndrome (see Media file 1), tuberous sclerosis, phenylketonuria, neurofibromatosis, Down syndrome, and congenital rubella. Roughly 10% of patients with PDD present with a known medical disorder. Seizures are the most frequent comorbidity.
Failure to Thrive
Hearing Impairment
Mood Disorder: Depression
Schizophrenia and Other Psychoses
Other Problems to be Considered
Reactive attachment disorder
Landau-Kleffner syndrome
Schizotypal personality disorder
Mental retardation
Lab Studies
- Fragile-site mental retardation 1 gene (FMR1) DNA testing for fragile X syndrome is indicated.
- High-resolution cytogenetic studies with fluorescence in situ hybridization (FISH) is used to test for 15q duplication.
- If the history or physical findings suggest additional concerns, consider the following:
- High-resolution cytogenic studies with FISH testing for Prader-Willi, Angelman, and Williams syndromes
- Creatine phosphokinase measurement - To rule out muscular dystrophy
- Determination of lead level - To rule out lead poisoning
- Urine organic acid test
- Plasma amino acid test
- Lactate and/or pyruvate test - To rule out mitochondrial disorders
- Serum ammonia test - To rule out urea cycle defects
- Test for very long fatty acids - To rule out peroxisomal disorders
- Test of thyroid-stimulating hormone - To rule out hypothyroidism
Imaging Studies
- Brain MRI and not head CT may be helpful in the clinical assessment of global developmental delay, as the Practice Committee of the Child Neurology Society outlined in 2003.7
- Functional MRI, magnetic resonance spectroscopy (MRS), positron emission-tomography (PET) and single photon CT (SPECT) remain research tools. MRS is growing in promise as a tool in screening for conditions such as a deficiency in the creatine transporter gene.8
Other Tests
- Electroencephalography
- Results are abnormal in 25% of children with autism.
- Results are abnormal in all children with Rett syndrome.
- Results can be diagnostic for children with Landau-Kleffner syndrome because seizure activity in the brain speech centers often causes this rare disorder.
- Hearing test9
- Psychological and neuropsychological testing
- In older children, testing may help distinguish pervasive developmental disorder (PDD) not otherwise specified from a mood disorder, early presentation of schizophrenia, or schizotypal personality disorder.10
- Testing may reveal verbal and nonverbal learning disabilities.
Consultations
- Child psychiatrist, developmental/behavioral pediatrician
- To evaluate and treat comorbid diagnoses such as depression
- To lead multidisciplinary team for case management, which may include family psychoeducational therapy, psychopharmacologic treatment, speech therapy, occupational therapy, physical therapy, and behavioral therapy
- Psychologist, education specialist
- To assess baseline functions for intellectual capacity and learning disabilities
- To design cognitive behavioral strategies for facilitating education and for modifying difficult behaviors (This area is rapidly growing, with increasing evidence suggesting that specific types of therapy may be effective for early intervention that enhance generalization of social skills.)
Many types of medications are used to address different behavioral issues and comorbid disorders associated with pervasive developmental disorder (PDD). Recently, the US Food and Drug Administration (FDA) approved risperidone for use in children to treat irritability associated with autistic disorder.11 Data from several large randomized placebo-controlled trials suggest that antipsychotic medications may be helpful, particularly for aggression. In addition, treatment with antipsychotics may improve restricted, repetitive, and stereotyped patterns of behavior and interests. However, no medications substantially change deficits in social interaction and communication. The use of antipsychotic medications requires careful monitoring of weight, fasting lipid profile, and fasting plasma glucose as recommended by the consensus statement published in Diabetes Care.12
Further Inpatient Care
- Thorough medical evaluation is warranted before psychiatric hospitalization is considered.
- Inpatient care is warranted to manage acute medical issues or for a workup of subclinical medical disorders.
- Patients often present with medical problems that manifest as changes in behavior.
- Psychiatric hospitalization is indicated whenever the safety of the patient cannot be maintained.
Further Outpatient Care
Outpatient management requires a multidisciplinary approach.
- Comorbid medical problems, including seizures and constipation, are frequent.
- Certain behaviors may require medication by a child and adolescent psychiatrist or behavioral-developmental pediatrician.
- A speech pathologist's expertise is essential to develop a communication plan.
- A special education professional may be needed to design a specific curriculum for each child with pervasive developmental disorder (PDD).
- Occupational and physical therapists may be indicated for motor deficits and sensory processing deficits.
- A social worker not only helps find financial, educational, and emotional resources but also provides important psychosocial support for the family.
- Psychologists often develop behavioral plans and ongoing therapy to improve social relationships.
Patient Education
Medical/Legal Pitfalls
- Failure to conduct a thorough medical review: A thorough review is important because none of the pervasive developmental disorders (PDDs) has a medical cure. Treatable conditions may cause symptoms of PDD, or they may worsen behaviors associated with these disorders.
- Failure to suggest legal consultation: Many parents of children with PDD need legal guidance to help them understand their legal rights to benefits and services for their children from public schools and from the medical system.
This article is dedicated to Henrietta Leonard, MD (program director of child and adolescent psychiatry and professor of psychiatry and human development in the division of child and adolescent psychiatry at Rhode Island Hospital and Brown University) who passed away in August 2007. Dr. Leonard will be missed by many for her passion for teaching, highest ethical standards, and dedication to children's mental health. Without her, this chapter would never have been realized.
| Media file 1:
Young child with fragile X syndrome who does not have obvious dysmorphic features. |
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Media type: CT
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- APA. Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Washington, DC: APA; 1994.
- Redcay E, Courchesne E. When is the brain enlarged in autism? A meta-analysis of all brain size reports. Biol Psychiatry. Jul 1 2005;58(1):1-9. [Medline].
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- McDougle CJ, Scahill L, Aman MG, et al. Risperidone for the core symptom domains of autism: results from the study by the autism network of the research units on pediatric psychopharmacology. Am J Psychiatry. Jun 2005;162(6):1142-8. [Medline].
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- Sutcliffe JS, Delahanty RJ, Prasad HC, et al. Allelic heterogeneity at the serotonin transporter locus (SLC6A4) confers susceptibility to autism and rigid-compulsive behaviors. Am J Hum Genet. Aug 2005;77(2):265-79. [Medline].
- Volkmar F, Cook E Jr, Pomeroy J, et al. Summary of the Practice Parameters for the Assessment and Treatment of Children, Adolescents, and Adults with Autism and other Pervasive Developmental Disorders. American Academy of Child and Adolescent Psychiatry. J Am Acad Child Adolesc Psychiatry. Dec 1999;38(12):1611-6. [Medline].
Pervasive Developmental Disorder excerpt Article Last Updated: Mar 26, 2008
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