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Pervasive Developmental Disorder

Pervasive Developmental Disorder

Alternate Names

  • PDD


Pervasive developmental disorder, abbreviated as PDD, is a set of complex disorders that affect the brain. PDDs are characterized by an intense difficulty in social interactions and communication with others.

What is going on in the body?

PDD is a neurological disorder that affects the brain. It appears to affect the way a person reacts and interacts with others. PDD affects boys four times more often than girls. It is equally prevalent in people from all parts of society. There are several different disorders that fall under the category of pervasive developmental disorders.
  • Autistic disorder (autism) is the most severe of the PDDs. A person with autism has extreme difficulty in social interactions and communication. This is obvious before the age of 3 years.
  • Asperger's disorder includes symptoms of difficulty in social interactions and little interest in activities. There usually is no difficulty with language skills. The person may be average or above average for age in intellectual testing.
  • Rett's disorder is only seen in girls. It is characterized by normal behavior at first and then sudden loss of skills and loss of control of the hands. This is followed by repetitive hand gestures, such as flapping. Symptoms usually begin between the ages of 1 and 4 years.
  • Childhood disintegrative disorder (CDD) is a disorder in which normal development is seen until the age of 2 years and then a loss of social skills and a tendency toward autistic behavior occurs.
  • Pervasive developmental disorder-nonspecific may be considered when symptoms of the other disorders are not present but there is a considerable difficulty with specific behaviors.
Symptoms can vary in intensity in any of these disorders. Some people may have severe symptoms that affect their lives dramatically. Others have symptoms that they are easily able to compensate for.


What are the causes and risks of the disease?

The causes of PDD are not well known. Some cases may be genetic, although this has not been proven. What is known is that PDD is not caused by bad parenting, mental illness, or "that a kid just doesn't want to behave." Psychological factors have not been found to contribute to PDD.
Some cases of PDD have been associated with trauma, disease, or structural abnormalities before or during birth, including:
  • the mother having rubella, or German measles, while she was pregnant
  • untreated phenylketonuria, a problem in the body's ability to handle certain chemicals named phenylketones
  • lack of oxygen during birth
  • encephalitis or other serious infections affecting the brain as an infant
  • spasms from a variety of illnesses during infancy
After considerable study, researchers have concluded that PDDs are not linked to the receipt of childhood vaccines.


What can be done to prevent the disease?

Since the cause of PDD is not known, PDD can be difficult to prevent. Early recognition and treatment may reduce the effects of PDD.


How is the disease diagnosed?

A team of healthcare professionals should evaluate the person with PDD. The team may include a developmental physician, a psychologist, a neurologist, a speech therapist, and learning consultant. Diagnosis begins with a history and physical exam. Further testing is then needed to identify other possible causes of the symptoms. These include blood tests, cranial CT scans, cranial MRI scans, and electroencephalograms (EEGs).

Long Term Effects

What are the long-term effects of the disease?

Long-term effects of PDD depend on the severity of the symptoms, as well as on how soon a person starts treatment. The symptoms of PDD may last a lifetime, but often these can be improved with careful intervention and treatment. In other cases, PDD may cause struggles for a lifetime.

Other Risks

What are the risks to others?

Pervasive developmental disorders are not contagious. It is not yet clear if some causes of PDD are genetic. Genetic counseling may be useful to couples with a family history of PDD.


What are the treatments for the disease?

Treatment for PDD first focuses on education. This should be tailored to each person's specific needs and symptoms. Some of the treatments include:
  • behavioral therapy to help the person handle his or her environment
  • "inclusion programs" to help the person adapt to the outside world as much as possible
  • providing a structured environment for the person
  • audio-visual therapies
  • dietary review
  • medications, including antipsychotic medications, depending on the symptoms
  • music therapy
  • physical therapy
  • speech therapy
Treatment may also include teaching the person how to handle new situations. This can include asking for help, directions, and other needs. A person with a PDD often needs guidance in getting jobs and handling the daily work routine.
The families and friends of people with PDD need support as well. The more support they have, the better the adjustment to living with a person with PDD. Sometimes the person with PDD may need to live in a group home.

Side Effects

What are the side effects of the treatments?

Side effects depend on the treatments used. Behavioral therapy can cause frustration for the person and the family experiencing it. Each medication has its own set of side effects. Some of the more common of these are stomach upset, rash, irritability, depression, and allergic reactions.

After Treatment

What happens after treatment for the disease?

Treatment for PDD will usually last a lifetime. A person with a mild form of PDD may be able to monitor him or herself for when treatment needs to continue. A person with a more severe form of PDD may need assistance with treatment and therapy programs.


How is the disease monitored?

PDD needs to be monitored closely. Treatments need to be adjusted over time. Persons with a mild form of PDD may improve as they mature. Those with a more severe form of PDD may worsen over time and may need adjustments to their treatment program. They may also have to rely on a caregiver to monitor their behavior and help them get the care they need.

Sources Current Pediatric Diagnosis and Treatment, Hathaway, Hay, Groothuis, Paisley, 1993/ Professional Guide to Diseases, Springhouse,1995

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