F84: Pervasive developmental disorders

Pervasive developmental disorders (PDD) are a group of conditions that involve delays and impairments in several areas of development, including socialization and conversation. These disorders might be present from infancy, but may not fully manifest too noticeable until the child is a few years old. The exact causes are not known, but they are believed to result from a combination of genetic and environmental factors. Some common characteristics of these disorders include difficulties with using and understanding language, trouble relating to people, things, and events; playing in unusual ways with toys and other objects; uncommon behavior patterns, and many degrees of difficulty dealing with changes in routine. PDDs range in severity and manifestations and include conditions such as autism, Asperger's syndrome, and Rett's syndrome. The diseases can continuously evolve from childhood into adulthood, affecting the affected individual's ability to function socially, at school, at work, or in other areas of life.