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What are Pervasive Developmental Disorders?
In the current mental health Diagnostic and Statistical Manual (DSM IV), published by the American Psychiatric Association, pervasive developmental disorders (PDD) refer to five separate developmental diagnoses. This group of disorders, also called autism spectrum disorders, includes:
- Autistic Disorder
- Asperger Syndrome
- Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS)
- Rett Syndrome
- Childhood Disintegrative Disorder
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Pervasive developmental disorders are neurological conditions that affect the way an individual experiences his or her environment. The symptoms of pervasive development disorders can affect individuals very differently, depending on their severity and configuration. Some experience symptoms that are quite mild, while others can be severely impacted by these disorders. Some may seem to display all of the symptoms while others exhibit only a few. Autism spectrum disorders are lifelong, though individuals can learn to cope with some of the challenges. In general, those with PDDs experience qualitative impairments in three main areas: language and communication; social interaction and repetitive interests and patterns of behavior.
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Language and Communication
Children and adults with pervasive developmental disorders may:
- Have difficulty using or understanding language to communicate their needs
- Repeat or echo language that they have heard in the past (e.g. script from a movie)
- Have a very literal understanding of language and difficulty understanding idioms (e.g. It’s raining cats and dogs)
- Have limited understanding of body language, facial expression and tone of voice
Someone who has classic autism may have very little functional communication, or may use sign language or a communication device. On the other hand, a person with Asperger syndrome might have a high vocabulary and good oral language skills, but may miss the point of jokes, sarcasm or non-verbal communication.
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Those who have been diagnosed with PDD may:
- Seem uninterested in the people in their environment
- Have difficulty understanding and regulating their emotions
- Be unable to identify with the emotions or perspective of others
- Appear uninterested in playing
- Use toys differently than their intended purpose (e.g. spinning the wheels of a toy car, rather than driving it around a floor map)
Often, the individual with PDD is the student walking around the playground by themselves at recess, or the adult who sits in the work cafeteria by him or herself. Though they may seem to prefer isolation, this isn’t always the case. Difficulty understanding social dynamics and following conversation can make any situation difficult, but many individuals can learn appropriate social skills with support.
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Restrictive and Repetitive Patterns of Behavior
Individuals with pervasive developmental disorders may:
- Adhere rigidly to routines
- Have difficulty managing transitions
- Engage in repetitive physical movements (e.g. rocking, flapping, tapping)
- Show preference for familiar items
- Have intense preoccupations with specific topics or objects
People with PDD tend to prefer regular, structured routine and may have difficulty when that routine is changed. A loud school assembly, a two-week visit from Aunt Polly or a misplaced stuffed animal might be trying for the average person but for the child or adult with a PDD, these situations might seem devastating.
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Some symptoms of pervasive developmental disorders are not crucial in the diagnosis, but seem to affect many individuals on the autism spectrum. Many people with PDD may experience heightened or diminished sensitivities to sensory stimuli. For example, one person might display an adverse reaction to loud noises or certain textures while another may be less likely to react to intense pain.
Higher than average levels of anxiety in individuals with autism are common. This is understandable when you consider that we live in a very social world that can be difficult to predict. In fact, it is not uncommon for those with PDD to engage in challenging behavior, ranging from interrupting others to violent outbursts. These behaviors are not symptoms of PDD, per say. Rather, challenging behaviors may be a reaction to anxiety or sensory issues.
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Child Disintegrative Disorder
Child disintegrative disorder (CDD) is very rare, affecting only 2 of every 100,000 children diagnosed with pervasive developmental disorder. In CDD, symptoms are similar to those in the other disorders but regression follows a period of normal development until age 3 or 4. Symptoms of CDD also include loss of bowel and bladder control, development of seizure activity and loss of cognitive ability.
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Rett syndrome is also rare (in comparison to the other pervasive development disorders) and primarily affects girls at a rate of one in 10,000 to 15,000. Rett’s is also characterized by a regression in development, beginning between six and eighteen months. Symptoms include delay or regression in motor skills, reduced communication and social interaction, and compulsive wringing or washing hand movements.
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References & Resources:
Center for Disease Control and Prevention: Facts, Autism Spectrum Disorders, http://www.cdc.gov/ncbddd/autism/facts.html
National Institute of Mental Health, http://www.nimh.nih.gov/health/publications/autism/complete-index.shtml
White, S., Oswald, D., Ollendick, T. and Scahill, L. (2009). Anxiety in children and adolescents with autism spectrum disorders. Clinical Psychology Review, 29, 216–229.
Green, S.A., and Ben-Sasson, A. (2010). Anxiety disorders and sensory over-responsivity in children with autism spectrum disorders: Is there a causal relationship? Journal of Autism and Developmental Disorders, 40, 1495–1504.