Pervasive Developmental Disorder (PDD)

A group of conditions involving serious impairment in several areas of development, including physical, behavioral, cognitive, social, and language development.

The incidence of pervasive development disorders (PDDs) in the general population is estimated at 1%. These disorders are thought to be genetically based, and there is no evidence linking them to environmental factors. Many children who are diagnosed with PDDs today would have been labeled psychotic or schizophrenic in the past. The most serious form of pervasive developmental disorder is autism, a congenital condition characterized by severely impaired social interaction, communication, and abstract thought, and often manifested by stereotyped and repetitive behavior patterns.

In addition to autism, several other conditions are considered pervasive developmental disorders by the American Psychiatric Association. Rett's disorder is characterized by physical, mental, and social impairment that appears between the ages of five months and four years in children whose development has been normal up to that point. Occurring only in girls, it involves impairment of coordination, repetitive movements, a slowing of head growth, and severe or profound mental retardation, as well as impaired social and communication skills. Childhood disintegrative disorder is marked by the deterioration

This autistic child is encouraged to interact with the guinea pig in an effort to improve his social interaction. (Photo by Helen B. Senisi. Photo Researchers, Inc. Reproduced with permission.)

of previously acquired physical, social, and communication skills after at least two years of normal development. It first appears between the ages of two and 10, usually at three or four years of age, and many of its symptoms resemble those of autism. Other names for this disorder are Heller's syndrome, dementia infantilis, and disintegrative psychosis. It sometimes appears in conjunction with a medical condition such as Schilder's disease, but usually no organic cause can be found.

Asperger's disorder includes many of the same social and behavioral impairments as autism, except for difficulties with language. Children with this disorder lack normal tools of social interaction, such as the ability to meet someone else's gaze, use appropriate body language and gestures, or react to another person's thoughts and feelings. Behavioral impairments include the repetitive, stereotyped motions and rigid adherence to routines that are characteristic of autism. Like childhood disintegrative disorder, Asperger's disorder is thought to be more common in males than females.

Research based on autopsies and magnetic resonance imaging (MRI) of live patients shows that PDDs are connected with specific abnormalities in the brain. These conditions are usually evident in early childhood and often cause some degree of mental retardation. They are not curable, but there are a variety of treatments that can alleviate specific symptoms and help children function better in daily life. Drugs like Prozac, Zoloft, and Luvox, all selective serotonin reuptake inhibitors (SSRIs), can reduce aggression and repetitive thoughts and improve social interaction. Attention problems and hyperactivity respond to psychostimulants, such as Ritalin, Dexedrine, and Cylert, which can make children more responsive to other types of intervention. Behavior therapy has helped children with PDDs minimize negative behavior, such as repetitive activities and persistent preoccupations, and group therapy has helped improve social skills.

Education is an important component in the treatment of PDDs. Special education programs that address all types of developmental problems—social, linguistic, and behavioral—are mandated by federal law and available to children from the ages of four or five. Even those children with PDDs who can be enrolled in regular classes can benefit from supplemental special instruction programs. Speech, language, and occupational therapy can help children with PDDs, including autism, function at the highest level possible. In many cases, appropriate education and therapy from the earliest age can save these children from institutionalization.