Brain & Nervous System Guide to Autism What Is Atypical Autism? By Lisa Jo Rudy facebook twitter linkedin Lisa Jo Rudy, MDiv, is a writer, advocate, author, and consultant specializing in the field of autism. Learn about our editorial process Lisa Jo Rudy Medically reviewed by Medically reviewed by Pilar Trelles, MD on December 01, 2019 linkedin Pilar Trelles, MD, is board-certified in psychiatry and child and adolescent psychiatry. She is the medical director of the developmental disability center at Mount Sinai West Hospital. Learn about our Medical Review Board Pilar Trelles, MD on December 01, 2019 Print Table of Contents View All Table of Contents Autism and the DSM Atypical Autism Treatments Living With Autism Atypical autism or pervasive developmental disorder not otherwise specified (PDD-NOS) is a form of autism that was diagnosed from 1994 to 2013. It first appeared in the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) to encompass the many children who had some, but not all, symptoms of autism. Charly Franklin / Getty Images The next edition, the DSM-5 published in 2013, updated the diagnosis of autism to include a broader range of symptoms that fall under autism spectrum disorder (ASD), along with three levels to indicate support needs. Level 1 requires the least support, while Level 3 requires the most support. Most people who previously were given a diagnosis of PDD-NOS would likely receive a diagnosis of ASD under the new diagnostic criteria. Autism and the DSM The DSM is the American Psychiatric Association's manual that lists all mental and developmental disorders. There are five versions of the DSM, dating back to 1952. Unlike physical disorders, mental and developmental disorders are often based on social norms and each DSM update has new or revised diagnostic criteria and disorders. Autism was first classified as its own diagnosis in the DSM-III, published in 1980. Prior to that, children with autism-like behaviors were given a diagnosis of childhood schizophrenia. DSM-IV: PPD-NOS The DSM-IV was published in 1994 and divided autism into five separate diagnostic categories. Among these were autistic disorder, Asperger syndrome, and PDD-NOS. The term autism spectrum in the DSM-IV referred to pervasive developmental disorders (PDDs), a category of diagnoses with certain symptomatic similarities. Atypical autism was another name for one of the five official autism spectrum diagnoses: pervasive developmental disorder not otherwise specified (PDD-NOS). PDD-NOS referred to "presentations that do not meet the criteria for autistic disorder because of late age of onset, atypical symptomatology, subthreshold symptomatology, or all of these." The two main diagnostic criteria include: severe and pervasive impairment in the development of reciprocal social interaction or verbal and nonverbal communication skills;or when stereotyped behavior, interests, and activities are present, but the criteria are not met for a specific pervasive developmental disorder, schizophrenia, schizotypal personality disorder, or avoidant personality disorder. Characteristics of PDD-NOS are similar to autism but tend to be milder and include: Atypical or inappropriate social behaviorUneven skill development of skills, such as fine or large motor skills, visual or spatial organization, or cognitive skillsDelays in speech or language comprehensionDifficulty with transitionsDeficits in nonverbal and/or verbal communicationIncreased or decreased sensitivities to taste, sight, sound, smell and/or touchRepetitive or ritualistic behaviors A PDD-NOS or "atypical autism" diagnosis meant there were too few symptoms to be diagnosed with autistic disorder or Asperger syndrome, and the wrong symptoms to be diagnosed with Rett syndrome or childhood disintegrative disorder. DSM-5: Autism Spectrum Disorder When the DSM-5 was published 2013, it made the rather momentous decision to collapse all five of the autism diagnoses from DSM-IV into a single diagnostic category: autism spectrum disorder (ASD). A diagnosis of PDD-NOS is under the autism umbrella in the DSM-IV, and, according to the DSM-5, a diagnosis made under DSM-IV cannot be revoked. However, a person diagnosed with PDD-NOS may or may not fit the current criteria for autism. According to research published by Journal of the American Academy of Child and Adolescent Psychiatry in 2014, the majority of patients with a PDD-NOS diagnosis (63 percent) meet the criteria for autism spectrum disorder as outlined in DSM-5. The study also found that most prior PDD-NOS diagnoses that don't meet the current ASD criteria fit a diagnosis of social communication disorder (32%). The remaining 2% could be diagnosed with attention-deficit/hyperactivity disorder (ADHD) and anxiety disorder. Is It Autism or Social Communication Disorder? Atypical Autism Other terms to describe PDD-NOS include atypical autism, autistic tendencies, and autistic traits. But even among people with PDD-NOS or ASD can have a wide range of challenges. While some people with PDD-NOS have milder autism symptoms, that does not necessarily mean it is any less disabling. It is, in fact, quite possible to have this diagnosis and be severely disabled. However, many children and adults diagnosed with PDD-NOS have relatively mild symptoms. Could You or Your Child Have Mild Autism? A study published in the Journal of the American Academy of Child and Adolescent Psychiatry compared individuals with PDD-NOS to individuals with autism and Asperger syndrome, and found children with PDD-NOS could be placed into one of three subgroups: a high-functioning group (24%) who resembled Asperger syndrome but had a transient language delay or mild cognitive impairmenta subgroup resembling autism (24%) but who had late age of onset, too severe cognitive delays, or too young to potentially meet the full diagnostic criteria for autisma group (52%) not fulfilling the criteria for autism because of fewer stereotyped and repetitive behaviors. In terms of the level of functioning measures, the PDD-NOS children had scores that were between those of the children with autism and those of the children with Asperger syndrome. In contrast, the PDD-NOS group had fewer autistic symptoms, especially repetitive stereotyped behaviors, than the other groups. Treatments Regardless of the subcategory autism spectrum diagnosis, the treatments recommended are likely to be very similar no matter what the official autism spectrum diagnosis: intensive behavioral and/or developmental therapy, along with speech, occupational, and physical therapies, and social skills classes for older children. Autism Treatment Living With Autism Autism presents differently in individuals and the autism spectrum covers a wide range of autism profiles and levels of disability associated with ASD. While autism is typically diagnosed in children, it is not a disorder you outgrow. While early intervention and treatment can help to teach coping strategies, adults with autism and PDD-NOS can still struggle with social interactions, behavioral challenges, and perceptual problems. Diagnosing Autism Was this page helpful? Thanks for your feedback! Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Ousley O, Cermak T. Autism Spectrum Disorder: Defining Dimensions and Subgroups. Curr Dev Disord Rep. 2014;1(1):20–28. doi:10.1007/s40474-013-0003-1 Kim YS, Fombonne E, Koh YJ, Kim SJ, Cheon KA, Leventhal BL. A comparison of DSM-IV pervasive developmental disorder and DSM-5 autism spectrum disorder prevalence in an epidemiologic sample. J Am Acad Child Adolesc Psychiatry. 2014;53(5):500-8. Surís A, Holliday R, North CS. The Evolution of the Classification of Psychiatric Disorders. Behav Sci (Basel). 2016;6(1):5. Published 2016 Jan 18. doi:10.3390/bs6010005 Miller JS, Bilder D, Farley M, et al. Autism spectrum disorder reclassified: a second look at the 1980s Utah/UCLA Autism Epidemiologic Study. J Autism Dev Disord. 2013;43(1):200–210. doi:10.1007/s10803-012-1566-0 Regier DA, Kuhl EA, Kupfer DJ. The DSM-5: Classification and criteria changes. World Psychiatry. 2013;12(2):92–98. doi:10.1002/wps.20050 Kim YS, Fombonne E, Koh YJ, Kim SJ, Cheon KA, Leventhal BL. A comparison of DSM-IV pervasive developmental disorder and DSM-5 autism spectrum disorder prevalence in an epidemiologic sample. J Am Acad Child Adolesc Psychiatry. 2014;53(5):500-8. Autism Speaks. What is PDD-NOS? 2019 autismspeaks.org Volkmar FR, Reichow B. Autism in DSM-5: progress and challenges. Mol Autism. 2013;4(1):13. Published 2013 May 15. doi:10.1186/2040-2392-4-13 Huerta M, Bishop SL, Duncan A, Hus V, Lord C. Application of DSM-5 criteria for autism spectrum disorder to three samples of children with DSM-IV diagnoses of pervasive developmental disorders. Am J Psychiatry. 2012;169(10):1056-64. McPartland J, Volkmar FR. Autism and related disorders. Handb Clin Neurol. 2012;106:407–418. doi:10.1016/B978-0-444-52002-9.00023-1 Walker DR, Thompson A, Zwaigenbaum L, et al. Specifying PDD-NOS: a comparison of PDD-NOS, Asperger syndrome, and autism. J Am Acad Child Adolesc Psychiatry. 2004;43(2):172-80. Howes OD, Rogdaki M, Findon JL, et al. Autism spectrum disorder: Consensus guidelines on assessment, treatment and research from the British Association for Psychopharmacology. J Psychopharmacol. 2018;32(1):3–29. doi:10.1177/0269881117741766 Mason D, McConachie H, Garland D, Petrou A, Rodgers J, Parr JR. Predictors of quality of life for autistic adults. Autism Res. 2018;11(8):1138–1147. doi:10.1002/aur.1965 Additional Reading Allen DA, Steinberg M, Dunn M, et al. Autistic disorder versus other pervasive developmental disorders in young children: same or different? Eur Child Adolesc Psychiatry. 2001 Mar;10(1):67-78. Billstedt E, Gillberg IC, Gillberg C. Autism in adults: symptom patterns and early childhood predictors. Use of the DISCO in a community sample followed from childhood. J Child Psychol Psychiatry. 2007;48(11):1102-10. doi: 10.1111/j.1469-7610.2007.01774.x Kim YS, Fombonne E, Koh YJ, et al. A comparison of DSM-IV pervasive developmental disorder and DSM-5 autism spectrum disorder prevalence in an epidemiologic sample. J Am Acad Child Adolesc Psychiatry. 2014;53(5):500-8. doi: 10.1016/j.jaac.2013.12.021. NIH: National Institute of Child Health and Human Development. Autism Spectrum Disorders (ASD) Fact Page. www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Autism-Spectrum-Disorder-Fact-Sheet Walker DR, Thompson A, Zwaigenbaum L, et al. Specifying PDD-NOS: a comparison of PDD-NOS, Asperger syndrome, and autism. J Am Acad Child Adolesc Psychiatry. 2004;43(2):172-80. doi: 10.1097/00004583-200402000-00012