Others use the general category label of PDD because they are hesitant to diagnose very young children with a specific type of PDD, such as autism. Both approaches contribute to confusion about the term, because the term PDD actually refers to a category of disorders and is not a diagnostic label. Signs and symptoms
Symptoms of PDD may include behavioral and communication problems such as:

Difficulty using and understanding language
Difficulty relating to people, objects, and events; for example, lack of eye contact, pointing behavior, and lack of facial responses
Unusual play with toys and other objects. Paranoia, a characteristic form of social anxiety, derealization, transient psychosis, and unconventional beliefs if environment or routine are changed without notice
Repetitive body movements or behavior patterns, such as hand flapping, hair twirling, foot tapping, or more complex movements
Difficulty regulating behaviors and emotions, which may result in temper tantrums, anxiety, and aggression
Emotional breakdowns
Delusional or unconventional perception of the world
Maladaptive daydreaming
Mirrored-Self Misidentification – the delusion that the individual in the mirror that you are, is a child, even though you are an older teen or an adult

Degrees
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. Unusual responses to sensory information – loud noises, lights – are common. Diagnosis
Diagnosis is usually made during early childhood.
The diagnostic category pervasive developmental disorders (PDD), as opposed to specific developmental disorders (SDD), is a group of disorders characterized by delays in the development of multiple basic functions including socialization and communication. The pervasive developmental disorders include autism, Asperger syndrome, pervasive developmental disorder not otherwise specified (PDD-NOS, i.e., all autism spectrum disorders [ASD]), childhood disintegrative disorder (CDD), overactive disorder associated with mental retardation and stereotyped movements, and Rett syndrome. The first four of these disorders are commonly called the autism spectrum disorders; the last disorder is much rarer, and is sometimes placed in the autism spectrum and sometimes not.The terminology PDD and ASD is often used interchangeably and varies depending on location. The two have overlapping definitions but are defined differently by the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-V), and the International Classification of Diseases, 10th edition (ICD-10). DSM-V removed PDD as a diagnosis and replaced it with ASD and the relative severity of the condition. ICD-10 on the other hand labels ASD as a pervasive developmental disorder with the subtypes previously mentioned.The onset of pervasive developmental disorders occurs during infancy, but the condition is usually not identified until the child is around three years old. Parents may begin to question the health of their child when developmental milestones are not met, including age appropriate motor movement and speech production.There is a division among doctors on the use of the term PDD. Many use the term PDD as a short way of saying PDD-NOS (pervasive developmental disorder not otherwise specified).