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What Can We Learn from Studying Severe Autism?

Marina Sarris
Interactive Autism Network
Date Published: 
November 15, 2018

Research into autism has risen rapidly in recent decades, along with the autism rate itself. But has one group been left behind?

Yes, according to some researchers. In a recent editorial, Dr. Matthew Siegel, a child psychiatrist and researcher, says that research into people severely affected by the condition has declined.1 This group includes people who have few spoken words, have intellectual disability, or have challenging behaviors. These youth have a form of autism that resembles the condition originally described in 1943, in a landmark article by psychiatrist Leo Kanner.2

Dr. Siegel is not alone in his assessment. Older children who speak few words make up the "neglected end of the spectrum," according to other autism experts.3 Little is known about them because they have been left out of many research studies, those experts contend.

To reverse that trend, Dr. Siegel and other doctors and psychologists formed the Autism Inpatient Collection project, or AIC.4 The project has enrolled more than 1,000 youth ages 4 to 20 since it began in 2014. All were patients who had been admitted to special psychiatric units in one of six hospitals across the United States. Although hospital stays are relatively rare, children with autism are six times more likely to be hospitalized for psychiatric problems than other children.5

Early Results from the Autism Inpatient Study

watercolor painting of a boy in silhouette, from iStockAIC researchers have learned several things from these children, teens and young adults. Among them:

  • About one in four had been the victim of physical, emotional, or sexual abuse, and a small percentage of those youth had Post Traumatic Stress Disorder (PTSD).6
  • 22 percent of those who could speak had talked often about death or suicide.7
  • Coping skills were more important than verbal skills when it came to aggression and angry outbursts.8
  • Youth who spoke fluently experienced more depression, and more defiant and argumentative behavior, than those who did not.9
  • Five factors increased the risk of youth becoming hospitalized for psychiatric reasons. Mood and sleep disorders are numbers one and two on the list.10

Researchers modeled the inpatient study on another autism study, the Simons Simplex Collection (SSC). The SSC had enrolled more than 2,600 families who had only one child with autism. Both projects are funded by the Simons Foundation Autism Research Initiative. Like the Simons Simplex project, the AIC collects developmental history and genetic information from participants.

Researchers have already identified some genetic changes related to autism by studying Simons Simplex members, among others with autism.11-13 Now scientists will begin studying the DNA of AIC members to see what they can learn from them, Dr. Siegel said.

"Are we going to find a higher rate of genetic variations in this group versus less severely-affected groups, like the Simons Simplex Collection? That's the first and most basic question," said Dr. Siegel, who also directs the Developmental Disorders Program at Spring Harbor Hospital in Maine, and is associate professor of psychiatry and pediatrics at Tufts University. Youth in the Simons Simplex project, on average, have a higher IQ, better communication skills, and fewer psychiatric conditions than youth in the AIC, he explained.

Potential Barriers to Participating in Autism Research

Sometimes youth with more severe symptoms face obstacles to participating in autism studies, Dr. Siegel said. Their behaviors may make it hard for their families to take them to research centers, or for them to sit through the tests required to take part in studies. "We do have higher rates of behavioral and psychiatric challenges in the more severely affected folks, so just getting into those studies, and getting them through them, is probably more difficult."

The AIC project removes some of those barriers by collecting DNA and other information from the youth during their stay in one of the six hospitals, he said. Those hospitals are in Maine, Ohio, Colorado, Maryland, Pennsylvania, and Rhode Island.

He said he hopes scientists will learn more about severe autism and how best to help those with it. The project also may challenge certain ideas about autism that came from studies of people with milder symptoms, according to Dr. Siegel's editorial, "The Severe End of the Spectrum: Insights and Opportunities from the Autism Inpatient Collection."1 His article was published in the Journal of Autism and Developmental Disorders, which devoted a special issue to the AIC in November 2018.

Studying Autism along a Widening Spectrum

blue watercolor painting from PixabayStudies of "higher functioning" autism began in earnest a few decades ago, after psychiatrists began expanding the borders of the condition we now call autism spectrum disorder, or ASD. Autism is not diagnosed by blood tests or medical scans, but rather by how closely someone's symptoms fit a definition published in a psychiatric diagnostic manual. Those definitions may change every decade or so, when the manual is updated.

In the late 1980s, American psychiatrists added atypical autism, called Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS), to their diagnostic manual. A few years later they included Asperger's Disorder. People with PDD-NOS and Asperger's did not have all the symptoms found in the original definition of autism. Due to those changes, the number of people with "milder" autism grew – as did research on them. "It makes sense that, with an autism total population shift, that correspondingly research on those more severely affected would go down as a proportion of the total research landscape," Dr. Siegel said.

Other factors may be at play. Some research may be harder to do with youth who do not speak fluently, such as studies of how well talk-based therapies work for anxiety, he said.

Other autism studies exclude children with limited language or significant developmental delays because the tests needed for the research usually require the child to understand a certain amount of language.3 Some researchers are looking for tests that could be used reliably with people with few or no spoken words.

In a recently completed study, Dr. Siegel and his colleagues wanted to find out what proportion of autism research included those with severe autism. In order to do that, he said, they had to come up with a definition of severe autism.

Defining Severity in Autism

It’s a difficult question so perhaps that is why there is not an agreed upon definition in the field.

photo of Dr. Matthew Siegel, autism researcher and psychiatrist, of Spring Harbor Hospital in MaineWhat does it mean to have severe autism? "It’s a difficult question so perhaps that is why there is not an agreed upon definition in the field," Dr. Siegel said.

Does it mean having an IQ below a certain level, or being unable to speak in sentences? Articles in both the popular press and research journals sometimes refer to severe autism in those ways.

Since 2013, the psychiatric diagnostic manual has defined autism severity based upon the two main symptoms of autism: social communication problems, and repetitive behaviors and obsessive interests. A person with Level 1 (mild) autism might have trouble making friends, converse in odd ways, and have trouble switching between activities, according to the manual. A person with Level 3 (severe) autism, may have few spoken words, rarely make social overtures, and have "extreme difficulty coping with change."14

Dr. Siegel, and other researchers, are proposing a definition that he finds useful as a doctor who works with these youth. They looked at three major areas of functioning: communication ability, intelligence scores, and everyday living skills. "We picked those domains for several reasons," he said. "We thought these are the areas that have the most impact on someone's life and also are the most relevant to treatment."

Someone who scores in the bottom 2 percent of the general population on one of those measures – IQ, communication, or daily living skills – could be considered to be severely affected by autism, he said. Even someone with average IQ and verbal skills might fall into the severe category if he or she has severe struggles with daily living skills, under this proposal.

"We were coming at it from the standpoint of what do you need to know if you're going to treat someone," he explained.

Image credits: 1-2) iStock; 3) Pixabay, 4) Matthew Siegel, MD with permission.

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Additional Resources: 
  1. Siegel, M. (2018). The severe end of the spectrum: Insights and opportunities from the autism inpatient collection (AIC). Journal of Autism and Developmental Disorders, 48(11), 3641-3646. doi:10.1007/s10803-018-3731-6. Abstract
  2. Kanner, L. (1943). Autistic disturbances of affective contact. Nervous Child, 2, 217-250.
  3. Tager-Flusberg, H., & Kasari, C. (2013). Minimally verbal school-aged children with autism spectrum disorder: The neglected end of the spectrum. Autism Research : Official Journal of the International Society for Autism Research, 6(6), 468-478. doi:10.1002/aur.1329 [doi] Abstract.
  4. Siegel, M., Smith, K. A., Mazefsky, C., Gabriels, R. L., Erickson, C., Kaplan, D., . . . Autism and Developmental Disorders Inpatient Research Collaborative (ADDIRC). (2015). The autism inpatient collection: Methods and preliminary sample description. Molecular Autism, 6, 61-015-0054-8. eCollection 2015. doi:10.1186/s13229-015-0054-8 [doi] Abstract.
  5. Croen, L. A., Najjar, D. V., Ray, G. T., Lotspeich, L., & Bernal, P. (2006). A comparison of health care utilization and costs of children with and without autism spectrum disorders in a large group-model health plan. Pediatrics, 118(4), e1203-11. doi:118/4/e1203 [pii] Abstract.
  6. Brenner, J., Pan, Z., Mazefsky, C., Smith, K. A., Gabriels, R., Siegel, M., . . . for the Autism and Developmental Disorders Inpatient,Research Collaborative. (2018). Behavioral symptoms of reported abuse in children and adolescents with autism spectrum disorder in inpatient settings. Journal of Autism and Developmental Disorders, 48(11), 3727-3735. doi:10.1007/s10803-017-3183-4. Abstract.
  7. Horowitz, L. M., Thurm, A., Farmer, C., Mazefsky, C., Lanzillo, E., Bridge, J. A., . . . Autism and Developmental Disorders Inpatient Research Collaborative (ADDIRC). (2017). Talking about death or suicide: Prevalence and clinical correlates in youth with autism spectrum disorder in the psychiatric inpatient setting. Journal of Autism and Developmental Disorders, doi:10.1007/s10803-017-3180-7[doi]. Abstract.
  8. Williams, D. L., Siegel, M., Mazefsky, C. A., & Autism and Developmental Disorders Inpatient Research Collaborative (ADDIRC). (2017). Problem behaviors in autism spectrum disorder: Association with verbal ability and adapting/coping skills. Journal of Autism and Developmental Disorders, doi:10.1007/s10803-017-3179-0 [doi] Abstract.
  9. Lerner, M. D., Mazefsky, C. A., Weber, R. J., Transue, E., Siegel, M., Gadow, K. D., & Autism and Developmental Disorders Inpatient Research Collaborative (ADDIRC). (2018). Verbal ability and psychiatric symptoms in clinically referred inpatient and outpatient youth with ASD. Journal of Autism and Developmental Disorders, 48(11), 3689-3701. doi:10.1007/s10803-017-3344-5 [doi] Abstract
  10. Righi, G., Benevides, J., Mazefsky, C., Siegel, M., Sheinkopf, S. J., Morrow, E. M., & Autism and Developmental Disabilities Inpatient Research Collaborative (ADDIRC). (2017). Predictors of inpatient psychiatric hospitalization for children and adolescents with autism spectrum disorder. Journal of Autism and Developmental Disorders, doi:10.1007/s10803-017-3154-9 [doi] Abstract
  11. O'Roak, B. J., Deriziotis, P., Lee, C., Vives, L., Schwartz, J. J., Girirajan, S., . . . Eichler, E. E. (2011). Exome sequencing in sporadic autism spectrum disorders identifies severe de novo mutations. Nature Genetics, 43(6), 585-589. doi:10.1038/ng.835 [doi] Abstract
  12. O'Roak, B.,J., Vives, L., Fu, W., Egertson, J. D., Stanaway, I. B., Phelps, I. G., . . . Shendure, J. (2012). Multiplex targeted sequencing identifies recurrently mutated genes in autism spectrum disorders. Science (New York, N.Y.), 338(6114), 1619-1622. doi:10.1126/science.1227764. Abstract
  13. Bernier, R., Golzio, C., Xiong, B., Stessman, H. A., Coe, B. P., Penn, O., . . . Eichler, E. E. (2014). Disruptive CHD8 mutations define a subtype of autism early in development. Cell, 158(2), 263-276. doi:S0092-8674(14)00749-1 [pii] Abstract.
  14. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Arlington, VA: American Psychiatric Association.