Pervasive developmental disorder

The diagnostic category pervasive developmental disorders (PDD), as opposed to specific developmental disorders (SDD), refers to a group of disorders characterized by delays in the development of multiple basic functions including socialization and communication. Parents may note symptoms as early as infancy and typically onset is prior to 3 years of age. PDD is not fatal and does not affect normal life expectancy (however, an increased risk of suicide is associated with Asperger's syndrome).

Symptoms
Symptoms of PDD may include communication problems such as:
 * Difficulty using and understanding language
 * Difficulty relating to people, objects, and events
 * Unusual play with toys and other objects
 * Difficulty with changes in routine or familiar surroundings
 * Repetitive body movements or behavior patterns

Types and degrees
Autism, a developmental brain disorder characterized by impaired social interaction and communication skills, and limited range of activities and interests, is the most characteristic and best studied PDD. Other types of PDD include Asperger's syndrome, childhood disintegrative disorder, Rett syndrome, and PDD not otherwise specified (PDD-NOS). Children with PDD vary widely in abilities, intelligence, and behaviors. Some children do not speak at all, others speak in limited phrases or conversations, and some have relatively normal language development. Repetitive play skills and limited social skills are generally evident as well. Unusual responses to sensory information – loud noises, lights – are also common.

Diagnosis in early childhood
Some clinicians use PDD-NOS as a "temporary" diagnosis for children under the age of 5, when for whatever reason there is a reluctance to diagnose autism. There are several justifications for this: very young children have limited social interaction and communication skills to begin with, therefore it can be tricky to diagnose milder cases of autism in toddlerhood. The unspoken assumption is that by the age of 5, unusual behaviors will either resolve or develop into diagnosable autism. However, some parents view the PDD label as no more than a euphemism for autistic spectrum disorders, which makes it more difficult to receive aid for early intervention.

Cure and care
There is no known cure for PDD. Medications are used to address certain behavioral problems; therapy for children with PDD should be specialized according to the child's specific needs. Some children with PDD benefit from specialized classrooms in which the class size is small and instruction is given on a one-to-one basis. Others function well in standard special education classes or regular classes with support. Early intervention including appropriate and specialized educational programs and support services plays a critical role in improving the outcome of individuals with PDD.

Reference

 * The ADHD-Autism Connection: A Step toward more accurate diagnosis and effective treatment. By Diane M. Kennedy. ISBN 1578564980 – The aim of this book is to explore the similarities that attention-deficit hyperactivity disorder (ADHD) shares with pervasive developmental disorders.