Pervasive developmental disorders (PDD) — now known as autism spectrum disorder (ASD) — refers to a group of conditions that affect average development. It may appear as a delay in development of social and communication skills.

Signs of this condition usually become noticeable around the age of 3 years but can appear from early infancy.

The terms “pervasive developmental disorders” and “autism spectrum disorder” were previously used interchangeably by doctors. Doctors often diagnose “pervasive developmental disorder-not otherwise specified (PDD-NOS)” when a person has some core characteristics of autism but not others.

This article looks at the diagnosis of developmental disorders and ASD, as well as intervention and treatment options.

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PDD-NOS is one of several separate subtypes of autism that is now included under the umbrella term “autism spectrum disorder.”

The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders V (DSM-5) replaced the DSM-4 in 2013 and altered the diagnostic definition of autism.

The DSM-4 listed five pervasive developmental disorders:

The DSM-5 replaced autistic disorder, Asperger’s disorder, and PDD-NOS with the term autism spectrum disorder (ASD). However, people still commonly use the terms Asperger’s and PDD-NOS.

Doctors may diagnose PDD-NOS when a person does not meet the full criteria for the other four PDDs. A person may have some but not all of the characteristics of autism.

For example, they may have significant symptoms in one core area, such as restricted, repetitive behaviors. However, they may have few symptoms in another core area, such as social deficits.

Learn about parenting children with ASD here.

PDD-NOS usually first appears in young children, often before the age of 3. Signs of PDD-NOS may include:

  • difficulty understanding and using language
  • difficulty relating to people, events, or objects
  • playing unusually with toys or objects
  • finding changes to routine or familiarity difficult
  • repetitive body movements or patterns of behavior
  • limited social skills
  • responding unusually to sensory input, such as loud noises or bright lights

Speech and behavior may vary between each child. Some may have limited speech, and others may not speak at all. Others may have language development similar to same-age peers.

Learn about symptoms of autism in a 3-year-old here.

Many organizations and healthcare professionals may use the DSM-5 to diagnose ASD.

In some cases, people who received a PDD-NOS diagnosis before DSM-5’s release in 2013 may choose to have a re-diagnosis to determine which services they are eligible to get support from.

The American Academy of Pediatrics (AAP) recommends that all children aged 18–24 months old undergo screening for ASD.

To diagnose ASD, a team of healthcare professionals will assess the diagnostic criteria for ASD and conduct a thorough evaluation. This may include:

  • medical history of the maternal pregnancy
  • assessing developmental milestones and any sensory challenges
  • medical history, including any ear infections or seizures
  • family history of developmental disorders, genetic, or metabolic disorders
  • assessing cognitive function and language skills
  • a specific observational test, rating scale, or interview to determine ASD

Treatments vary depending on the specific needs of each individual. A therapist specializing in treatments for ASD can provide sessions that help develop a wide range of skills, including language and social skills. One-to-one support in the classroom or specialized education programs may help children with PDD.

Behavioral interventions help to decrease negative behaviors and increase positive behaviors. Family counseling may also be beneficial for the families of people with ASD.

Certain medications may help with conditions associated with ASD, such as anxiety or obsessive-compulsive disorder. If severe behavioral problems are present, certain types of antipsychotic medication may help.

People with ASD are at an increased risk of seizures, so doctors may prescribe anticonvulsant drugs to help manage them. If attention deficit disorder is present, medications can help ease impulsive or hyperactive behaviors.

Learn more about ASD here.

A combination of genetics and environment may cause ASD. Changes in how the brain develops in the early stages may play a role. Researchers have also identified certain genes that link to ASD.

There is no evidence that childhood vaccinations increase the risk of ASD.

Risk factors for ASD include:

  • having a sibling with ASD
  • having older parents
  • certain genetic conditions, such as Down syndrome or fragile X syndrome
  • very low birth weight

A team of healthcare professionals can help support people with ASD and their families, including behavioral therapists, language and social skills support, and family counselors.

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Early treatment of ASD includes specific educational programs and support services. They are a vital part of improving the outlook for people with ASD. ASD does not affect life expectancy.

The National Institute of Neurological Disorders and Stroke states that in many cases, symptoms of ASD may improve with treatment and as a child gets older.

If children under three have a regression of language skills, it may increase the risk of developing epilepsy. Some adolescents with ASD may experience depression or behavioral issues.

Some people with ASD may be able to live independently and healthily and may be able to communicate and interact well with others in a supportive setting.

PDD-NOS is a subtype of autism, a developmental disorder that affects development milestones related to things such as communication and social skills.

The DSM-5 uses the umbrella term ASD to diagnose PDD-NOS. Symptoms may first occur in young children, often before they are 3.

Early treatment and interventions may help improve the outlook for people with ASD. Behavioral, social, and language therapy, along with medication, may all help manage symptoms.