The diagnostic category pervasive developmental disorders (PDD), as opposed to specific developmental disorders (SDD), refers to a group of five disorders characterized by delays in the development of multiple basic functions including socialization and communication. The pervasive developmental disorders are:
- Pervasive developmental disorder not otherwise specified (PDD-NOS), which includes atypical autism, and is the most common;
- Autism, the best-known, now understood to be part of a spectrum;
- Asperger syndrome;
- Rett syndrome; and
- Childhood disintegrative disorder (CDD).
The first three of these disorders are commonly called the autism spectrum disorders; the last two disorders are much rarer, and are sometimes placed in the autism spectrum and sometimes not.
The onset of pervasive developmental disorders occurs during infancy, but the condition is usually not identified until the child is around 3 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. 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.
Classification
The pervasive developmental disorders are:
- Pervasive developmental disorder not otherwise specified (PDD-NOS), which includes atypical autism, and is the most common (47% of diagnoses);
- Autism, the best-known;
- Asperger syndrome (9% of autism diagnoses);
- Rett syndrome; and
- Childhood disintegrative disorder (CDD).
The first three of these disorders are commonly called the autism spectrum disorders; the last two disorders are much rarer, and are sometimes placed in the autism spectrum and sometimes not.
In May 2013, the Diagnostic and Statistical Manual-Fifth Edition (DSM-5) was released, updating the classification for pervasive developmental disorders. The grouping of disorders, including PDD-NOS, Autism, Asperger Syndrome, Rett Syndrome, and CDD, has been removed and replaced with the general term of Autism Spectrum Disorders. The American Psychiatric Association has concluded that using the general diagnosis of ASD supports more accurate diagnoses. The combination of these disorders was also fueled by the standpoint that Autism is characterized by common symptoms and should therefore bear a single diagnostic term. In order to distinguish between the different disorders, the DSM-5 employs severity levels. The severity levels take into account required support, restricted interests and repetitive behaviors, and deficits in social communication.
PDD and PDD-NOS
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. Others use the general category because the term PDD actually refers to a category of disorders and is not a diagnostic label.
PDD is not itself a diagnosis, while PDD-NOS is a diagnosis. To further complicate the issue, PDD-NOS can also be referred to as "atypical personality development", "atypical PDD", or "atypical Autism".
Because of the "NOS", which means "not otherwise specified", it is hard to describe what PDD-NOS is, other than its being an autism spectrum disorder (ASD). Some people diagnosed with PDD-NOS are close to having Asperger syndrome, but do not quite fit. Others have near full-fledged autism, but without some of its symptoms. The psychology field is considering creating several subclasses within PDD-NOS.
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
- Difficulty with changes in routine or familiar surroundings
- Repetitive body movements or behavior patterns, such as hand flapping, hair twirling, foot tapping, or more complex movements
- Inability to cuddle or be comforted
- Difficulty regulating behaviors and emotions, which may result in temper tantrums, anxiety, and aggression.
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 as well. Unusual responses to sensory information â€" loud noises, lights â€" are also common.
Diagnosis
Diagnosis is usually made during early childhood. With the release of the DSM-5 in May 2013, the diagnosis for PDD has been removed and replaced with autism spectrum disorders. Distinction between the past disorders is implicated by a series of severity levels. Individuals who received diagnoses based on the DSM-IV should still maintain their diagnosis under the autism spectrum disorders. A study published in the October 2012 issue of American Journal of Psychiatry, found that 91% of children with PDD diagnoses from the DSM-IV retained their diagnosis under the autism spectrum disorders diagnosis using the new DSM-5.
Due to the recent release of the new diagnostic criteria, the shift in classification and diagnoses will be gradual. Additionally, the replacement of pervasive developmental disorders with autism spectrum disorders has faced great criticism from those with past diagnoses and their family members.
Before the release of the DSM-5, some clinicians used PDD-NOS as a "temporary" diagnosis for children under the age of five when, for whatever reason, they are reluctant to diagnose autism. There are several justifications for this. Very young children have limited social interaction and communication skills to begin with, so it can be tricky to diagnose milder cases of autism in toddlers. The unspoken assumption is that by the age of five, unusual behaviors will either resolve or develop into diagnosable autism. However, some parents view the PDD label as no more than a euphemism for autism spectrum disorders, problematic because this label makes it more difficult to receive aid for early childhood intervention.
Care
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, play a critical role in improving the outcome of individuals with PDD.