Autism and Other Pervasive Developmental Disorders

About Pervasive Developmental Disorders

The term pervasive developmental disorders (PDDs) refers to a group of developmental conditions that affect children and involve delays or impairments in communication and social skills. Autism is the most well-known of the pervasive developmental disorders, so PDDs also are known as autism spectrum disorders.

PDDs also include Asperger syndrome and two less common conditions called childhood disintegrative disorder and Rett syndrome. Typically, PDDs are first diagnosed during infancy, toddlerhood, or early childhood.

All pervasive developmental disorders affect communication and social skills, as well as cognitive skills and behavior. All PDDs have things in common, but each has specific characteristics that set it apart from the others.

Signs of a PDD

Signs of a PDD are usually recognizable before a child is 3 years old. However, symptoms can range from severe to so subtle that they seem to be normal aspects of a young child's development. For that reason, it may take a few years for a PDD to be fully identified.

Early signs of a PDD can include:

• trouble interacting, playing with, or relating to others
• avoiding eye contact; not looking at people
• not pointing to objects to direct a parent's attention to things
• unusual movements, such as hand flapping, spinning, or tapping
• delays in developmental milestones or loss of milestones already achieved
• playing with the same toy in a way that seems odd or repetitive
• not using or understanding language
• not exploring environment with curiosity or interest

Children who show a pattern of these behaviors should be evaluated by their doctor. There are no blood tests or brain tests (such as MRIs) that diagnose PDDs, although such tests may be used to check for other conditions besides a PDD.

A diagnosis is made by a doctor with expertise in PDDs, such as a pediatric neurologist, developmental pediatrician, pediatric psychiatrist, or pediatric psychologist. Parent questionnaires, educational and cognitive assessments, language assessments, or play and behavior assessments might be used to help diagnose a PDD.

What Causes PDDs?

Causes of pervasive developmental disorders are not yet well understood. Scientists believe they are complex neurobiological (brain biology) problems, which may have a genetic basis like other conditions that stem from abnormalities in the chromosomes a child inherits.

Some studies have suggested that PDDs might stem from a host of causes, including food allergies, excessive amounts of yeast in the digestive tract, and exposure to environmental toxins. However, these theories have not been scientifically proven.

The weight of scientific evidence indicates that there is not a link between vaccines — or any of their ingredients — and autism. All in all, the risks of serious reactions to vaccinations are small compared with the health risks associated with the often-serious diseases they're intended to prevent. But if you have concerns about any vaccine for your child, don't hesitate to talk to your doctor. Ask about the benefits and risks of each vaccine and why they're so important for kids of all ages.