Pervasive Developmental Disorder

Pervasive Developmental Disorders, or PDDs, can affect children during early stages of development
Pervasive Developmental Disorders, or PDDs, can affect children during early stages of development. See more parenting pictures.
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Your happy, healthy baby seems to be right on track with his development. Then you enter the toddler years, and something seems different. Maybe he's not speaking or trying to verbalize the way other children do. Or he refuses to socialize, shutting himself off from contact with others. Maybe he becomes fixated on an object or activity and repeats it an abnormal number of times. You take your child to the doctor, and after a battery of tests, questionnaires and assessments, the doctor comes up with a diagnosis of Pervasive Developmental Disorder. What exactly does that mean?

Pervasive Developmental Disorders (also referred to as PDDs) are a category of developmental conditions that can affect children during the crucial stages of early development. A child with a PDD has some kind of delay in the formation of his behavior and communication skills. PDDs affect a person's basic skills such as speech, socialization and imagination. Although children may have symptoms of PDD at a very early age, they may not be truly noticeable until around age three, when it's more obvious that a child is not developing language or socialization skills at the same rate as others in his age bracket. Boys tend to develop PDDs more often than girls.


Because PDDs affect a child's behavior and communication, social and cognitive skills, some experts feel the label "pervasive" may be misleading. The term means "to become spread throughout all parts of," and while the child with PDD doesn't have fully pervaded development, it doesn't mean that every child with PDD has greatly retarded development, either. Nor does it mean that the disorder affects every aspect of a child's development. Some children may be severely affected by their PDD, but in others, it can be barely noticeable [Source:, WebMD]. There are no cures for PDDs, but people with one may benefit from medication, therapy or both.

Five types of diagnoses fall into the PDD category, and each type of disorder can range from mild to severe, depending on the child. On the next pages, we'll look at these five PDDs and their characteristics.



Different Pervasive Development Disorders

Some disorders, like autism, may require special treatment, such as guide dogs.
Some disorders, like autism, may require special treatment, such as guide dogs.
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Five major conditions make up the pervasive developmental disorder diagnosis:

  • Autism -- The most well known PDD, autism is a neurological developmental disorder that can affect one in every 150 people [Source: WebMD]. Autistic people have problems with verbal and nonverbal communication and social interaction, and they display excessive repetition or an obsession with narrow interests. A majority are also mentally retarded. Autism does not affect every child the same way, so to that end, autism is also referred to as autism spectrum disorder. This spectrum allows for variances in behavioral patterns and skills in those with autism, from mild to highly debilitating.
  • Asperger's syndrome -- This syndrome, named for Viennese pediatrician Hans Asperger, is considered by many medical professionals to be part of the autism spectrum. Children with Asperger's are often high functioning and intelligent, but they can have poor social skills and communication issues. Other typical traits of Asperger's include problems reading body language, understanding humor and creating obsessive routines or interests. Some children with Asperger's may be unusually sensitive to sensory stimuli that other people aren't bothered by, such as lights or noises.
  • Childhood disintegrative disorder -- This is a rare condition in which children's skills regress over time. Children with this condition have normal development, but when they're between two and ten, they lose many of their abilities and skills. This can include social and language skills, but it also many include motor skills and other learned functions like bowel and bladder control. Mental retardation is a high possibility in children with this disorder.
  • Rett's syndrome -- This is another rare disorder that affects girls only, because it's caused by a gene mutation on the X chromosome. Boys who are born with this syndrome die at a very young age because the disease affects them more severely. A girl with Rett's develops normally, but the syndrome kicks in when they're between six and 18 months old. Rett's attacks girls both physically and mentally. Language skills deteriorate until the girl can no longer speak, and sufferers also lose muscle tone and coordination, walk stiffly, and lose meaningful use of their hands. They may also experience seizures.
  • Pervasive developmental disorder not otherwise specified (PDDNOS) -- PDDNOS is a condition similar to autism in that children may have communicative or sensory impairment, but they don't develop other marked characteristics of autism. Children with PDDNOS are generally more social than children with autism.

Next, we'll look at how you can see the symptoms of PDD.


Signs of Pervasive Developmental Disorder

Some children may show difficulty relating to objects.
Some children may show difficulty relating to objects.
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The symptoms of PDD are different for each child and can manifest themselves at different times in a child's development, but there are many common threads that can help diagnose a PDD.

  • Impaired social interaction -- Children with PDD may become unresponsive, indifferent and avoid eye contact. They may seem withdrawn and have trouble relating to people. They may also talk for long periods about a particular topic without the ability to sense whether the person they're talking to wants to engage in or change the conversation. These children may have difficulty making friendships and empathizing with others.
  • Unusual play -- Children with PDD may have trouble relating to objects, sometimes fixating on one part of a toy. They may also fixate on an item so intently that they exclude others.
  • Repetitive movement -- Repetitive motions are another signal of PDD. Rocking back and forth, spinning or flapping hands are all typical signs. Children may have self-abusive behaviors and can be known to bite themselves or bang their head against a wall.
  • Communication issues -- Children with PDD may learn to communicate later in life. They might also learn to talk, then lose their ability to do so. Before they learn how to speak, they tend not to babble or point for things they want. They may have difficulty both using and understanding language or interpreting body language and facial expressions.
  • Sensory issues -- Many children with PDD have sensory problems. This can manifest itself as being extremely sensitive to light, being unable to hear some sounds or experiencing different ways the skin feels things.
  • Excessive behavioral problems -- Extreme temper tantrums, aggressive behavior, sleeping problems, fearfulness, anxiety, and being unable to stray from a set routine or familiar surroundings are all signs of a possible PDD.
  • Physical characteristics -- In the case of Rett's syndrome, some of its first signs are physical problems. Growth of the head will slow down, and girls may lose muscle tone.

Once diagnosed with PDD, a patient has many options for treatment. As we mentioned before, there's no cure for PDD, but many people with PDDs can be high functioning. With proper treatment, others may lead rich and full lives. On the next page, we'll explore the different options.


Dealing with Pervasive Developmental Disorder

Michael Dedrick-Dwyer, who has autism, takes 30-minute ride on a horse with therapist Rebecca Reubens in Coconut Creek, Fla.
Michael Dedrick-Dwyer, who has autism, takes 30-minute ride on a horse with therapist Rebecca Reubens in Coconut Creek, Fla.
Tom Ervin/Getty Images

While all individuals who have PDD suffer from it differently, many treatments can help ease some of the symptoms of the disorder. Early intervention and creating a treatment program can be very beneficial to sufferers of PDD.

There's no cure-all for every person with PDD. Because PDD affects people differently, treatments also vary greatly by the individual, so what works for one child with PDD may not necessarily work for another. It's important to work with your doctor to correctly diagnose the type of PDD your child has. A childhood development disorder specialist may also be called in to help with diagnosis and treatment.


Some children benefit from medication that will treat certain behavioral problems, such as anxiety, or help combat other medical issues the PDD brings on, such as seizures. Different types of therapy can also be extremely helpful. Some benefit from therapy that can help with communication skills or obsessive routines. Cognitive behavior therapy can help children become aware of troubling situations and help them develop the skills needed to deal with them. Physical, occupational and sensory therapy may help with the clumsiness aspects of PDD. Art therapy and music therapy may also be beneficial. In some cases, special diets may ease symptoms.

Programs can be developed both in school and at home to help children improve their socialization and communication skills. Programs in a school setting may also help reduce various behaviors that prevent the child from learning and functioning normally. In school some children may thrive in small classrooms with individual instruction. Others may benefit from standard special education classes. Some even do well in regular, mainstreamed classes and don't need any specialized support.

In severe cases, children with PDDs may not be able to live independently at any point in their lives. Particularly with childhood disintegrative disorder, children may need full-time professional care in a group home or similar facility.

Although it can be time-consuming and frustrating to find the proper diagnosis and develop a treatment plan, parents can do well by educating themselves about PDD, finding the right team for their child and getting support from other families who are dealing with PDD. For lots more information on pervasive developmental disorders, see the links on the next page


Lots More Information

Related HowStuffWorks Articles

  • "Asperger Syndrome: An Autism Spectrum Disorder." Reviewed on April 2008. (Feb. 26, 2010)
  • "Autism and other pervasive developmental disorders." Reviewed on April 2008. (Feb. 26, 2010)
  • "Asperger's Syndrome." Nov. 18, 2008. (Feb. 26, 2010)
  • "Childhood disintegrative disorder." Sept.16, 2008. (Feb. 26, 2010)
  • National Institute of Neurological Disorders and Stroke. "Autism Fact Sheet." Oct. 19, 2009. (Feb. 26, 2010)
  • National Institute of Neurological Disorders and Stroke. "NINDS Asperger Syndrome Information Page." Oct. 19, 2009. (Feb. 26, 2010)
  • National Institute of Neurological Disorders and Stroke. "NINDS Pervasive Developmental Disorders Information Page." Oct. 19, 2009. (Feb. 26, 2010)
  • "Autism." May 19, 2008. (Feb. 26, 2010)
  • "Pervasive Development Disorders (PDDs)." Reviewed on Sept. 3, 2009. (Feb. 26, 2010)
  • "Rett Syndrome." Reviewed on Sept. 3, 2009. (Feb. 26, 2010)
  • Yale University. "Pervasive Developmental Disorder - Not Otherwise Specified (PDD-NOS)." Dec. 16, 2009. (Feb. 26, 2010)