ADHD, Anxiety and Autism?

Marina Sarris
Interactive Autism Network at Kennedy Krieger Institute

Date Published: January 23, 2014

A boy with autism fidgets as he struggles to stay focused and calm in class. Down the hall, a girl with Asperger's Syndrome bolts from the class when her anxiety gets to be too much.

Are these behaviors just a part of autism spectrum disorder, or do these children have another psychiatric condition? Does it matter?

Some researchers believe that conditions such as Attention Deficit Hyperactivity Disorder (ADHD), anxiety disorder, Obsessive Compulsive Disorder (OCD) and depression are "under-recognized" in youth with autism, which, in turn, "hampers clinical care and treatment."1 After all, how can you treat what you don't diagnose?

The cost of untreated conditions may be high. Depression, for example, may put someone with autism at risk for suicide, withdrawal and aggression.2

Health care providers have a variety of treatments for anxiety, attention-deficit, obsessive-compulsive and other disorders in their arsenal. "There is no specific treatment for autism, but there are treatments for many of the [other] psychiatric disorders that occur in children with autism," concluded one group of researchers.3

What's Known About Multiple Diagnoses?

Research into the co-existence of psychiatric disorders with autism is limited. Some doctors have believed that anxiety, obsessiveness, inattention and hyperactivity are part of autism itself. Until 2013, in fact, the manual that physicians used to diagnose psychiatric conditions told them not to diagnose ADHD in children with autism.4 However, many health care providers did so anyway, according to a study by the Interactive Autism Network (IAN).14

One group of researchers acknowledged the difficulty in learning how many people with autism have other mental conditions. "Various types of anxiety are believed to be so common in autism that symptoms of anxiety disorders have been thought by some clinicians and investigators to be aspects of autism," rather than separate conditions, they said.3

Studies have found widely varying rates of other psychiatric problems among people with autism, depending on the population studied and the methods used. Those co-occurring conditions include: depression (affecting 2 to 30 percent), ADHD (affecting 29 to 83 percent), OCD (1.8 to 81 percent), and other anxiety disorders (2.9 to 35 percent).1, 3, 5-8, 14

OCD is a type of anxiety disorder marked by obsessions and compulsive rituals that are time-consuming and distressing. The huge variation in rate is likely due to different methods of assessing OCD and judging impairment from it.3

The new diagnostic manual, published in 2013, acknowledges that most people with autism have psychiatric symptoms that are separate from autism itself. About 70 percent of them "may have" another mental disorder and 40 percent "may have two or more" such disorders, according to the fifth edition of the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, or DSM-5.9 That manual, sometimes called the psychiatrists' "bible," urges doctors to diagnose ADHD, anxiety, depression and other co-morbid conditions in people with autism when appropriate. A co-morbid condition is one that occurs along with autism.

A study of 112 children with ASD found that 70 percent of them had at least one other diagnosis and 41 percent had two or more, including social anxiety disorder, ADHD and oppositional defiant disorder (ODD).10 People with ODD have a pattern of angry or irritable moods, defiant behavior or vindictiveness.

Special Challenges for People With Two or More Disorders

Having a child with more than one disorder presents special challenges to families, according to several parents who participated in the Simons Simplex Collection autism research project. In interviews, several said their children with autism spectrum disorder also have conditions such as OCD, anxiety, bipolar disorder or ADHD.

One mother, whose teenage son has ADHD and autism, said it can be hard teasing apart which condition is causing which symptoms. "I have a hard time deciphering which is which, the ADHD or autism," she said. One thing of which she is certain, "Without the ADHD medication, his aggression is difficult to manage."

Having a second diagnosis can lead to better, more effective treatment for the children, said parents in the Simons project. There are medications and therapies proven to work in both OCD and ADHD, for example.

Kriston Norris, whose family was profiled in "Learning to Adapt," said her son with autism was helped by OCD treatments after receiving an OCD diagnosis. She also sought help from his school after learning her son also has OCD. Knowledge of a second diagnosis can help teachers craft an Individualized Education Program (IEP) or school accommodations that address all of a student's needs, not just the main symptoms of autism.

For some parents, the pursuit of another diagnosis led to new insights into their child's challenges.

One mother said her son was diagnosed with autism at age 3 and bipolar disorder at 5. Her son always had problems with muscle tone, which was believed to be "part of autism," she said. However, in 2013, a doctor diagnosed her son with a duplication of the 15q chromosomal region, a genetic condition that may explain all of his symptoms. Doctors find these duplications more often in children with autism, intellectual disability or other developmental delays.11

Her son's bipolar disorder falls into the general category of mood disorder, along with depression. Mood disorders are not uncommon in autism. Neither is medication use. A study of 1,605 children in the Simons Simplex project found that two out of five had used psychiatric medication, primarily ADHD drugs, antidepressants and "mood stablizers."12 Mood stabilizers include antipsychotic drugs, seizure medicine and lithium, which is often used to treat bipolar disorder.

A smaller study of 160 children with ASD found that about one-fourth of them had a mood disorder and almost a third had "aggressive/self-injurious behaviors." That study found some children who appeared to have OCD, but researchers did not report the number because they could not "reliably" distinguish between OCD and "autistic rituals."13

The Art of Diagnosis

That raises another issue identified in several research studies: how do you diagnose certain conditions in people with autism if they have problems describing their symptoms? Even if a patient has some language, will he describe his emotions or obsessions in the same way as someone who doesn't have autism? "This type of information can only be elicited in older, verbal, less severely affected individuals," according to one research team.13

The psychiatric manual (DSM-5) offers some advice on this. A change in sleep or eating, and an increase in "challenging behavior, should trigger an evaluation for anxiety or depression" in people with autism who have limited or no language.9

But do the tools used to diagnose other psychiatric conditions work well when used with people with autism? Outside of a research setting, health care providers do not have "standardized scales" for assessing all other psychiatric disorders in people with ASD, according to the Interactive Autism Network study.14 That may complicate the process of diagnosing another mental disorder in someone with autism. A group of researchers tested a tool called the Autism Comorbidity Interview-Present and Lifetime Version several years ago; the tool would help doctors diagnose other conditions in people with autism. They concluded the tool was reliable but warranted further study among people of different ages, intelligence levels and verbal abilities.3

Thanks to scientific advances, doctors have come to understand that the boundaries between different disorders are blurrier than they believed just a decade or two ago. "Many symptoms assigned to a single disorder may occur, at varying levels of severity, in many other disorders," according to the DSM-5. Doctors will continue to use their clinical training and experience to sort it all out, the manual suggests.15

Paul H. Lipkin M.D., director of IAN, welcomes the changes in how children are diagnosed and treated. “While children with autism spectrum disorders share common social, behavioral, and communication difficulties, some have other developmental or behavioral problems that are not part of this diagnosis. With DSM-5, ASD is now considered distinct from these other conditions. This not only better highlights the individuality and special needs of each child or adult with ASD; it also allows family and professionals to target a person’s difficulties with more specific and, we hope, better therapies and medical treatments,” he said.

Thank you to the families of the Simons Simplex Collection who contacted us and who provided the idea for this article.

Additional Resources: 


  1. Joshi, G., Petty, C., Wozniak, J., Henin, A., Fried, R., Galdo, M., Kotarski, M., Walls, S. & Biederman, J. (2010) The heavy burden of psychiatric comorbidity in youth with autism spectrum disorders: a large comparative study of a psychiatrically referred population. J Autism Dev Disord. 2010 Nov;40(11):1361-70. View abstract.
  2. Matson, J.L. & Nebel-Schwalm, M.S. (2007) Comorbid psychopathology with autism spectrum disorder in children: An overview. Research in Developmental Disabilities 28 (2007) 341-352. View abstract.
  3. Leyfer, O.T., Folstein, S.E., Bacalman, S., et al. (2006) Comorbid psychiatric disorders in children with autism: Interview development and rates of disorders. Journal of Autism and Developmental Disorders. 2006;36:849-861. View abstract.
  4. American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disorders (4th ed., rev.). Washington, DC. (Pg. 74)
  5. Ghaziuddin, M., Ghaziuddin, N. & Greden, J. (2002) Depression in persons with autism: Implications for research and clinical care. Journal of Autism and Developmental Disorders. 2002;32:299-306. View abstract.
  6. Ghaziuddin, M. & Greden,  J. (1998) Depression in children with autism/pervasive developmental disorders: A case-control family history study. Journal of Autism and Developmental Disorders. 1998;28:111-115. View abstract.
  7. Wozniak, J., Biederman, J., Faraone, S.V., et al. (1997) Mania in children with pervasive developmental disorder revisited. Journal of the American Academy of Child and Adolescent Psychiatry. 1997;36:1552-60. View abstract.
  8. Muris, P., Steerneman, P., Merckelbach, H., Holdrinet, I. & Meesters, C. (1998) Comorbid anxiety symptoms in children with pervasive developmental disorders. Journal of Anxiety Disorders. 1998;12:387-393. View abstract.
  9. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Arlington, VA: American Psychiatric Publishing. (Pg. 58-59)
  10. Simonoff, E., Pickles, A., Charman, T., Chandler, S., Loucas, T. & Baird, G. (2008) Psychiatric disorders in children with autism spectrum disorders: prevalence, comorbidity, and associated factors in a population-derived sample. J Am Acad Child Adolesc Psychiatry. 2008 Aug;47(8):921-9. View abstract.
  11. Singer, E. (Aug. 30, 2012) Chromosome 15 duplications common in autism. Retrieved from
  12. Mire, S.S., Nowell, K.P., Kubiszyn, T. & Goin-Kochel, R.P. (2013) Psychotropic medication use among children with autism spectrum disorders within the Simons Simplex Collection: Are core features of autism spectrum disorder related? Autism. 2013 Sep 26. View abstract.
  13. Ming, X., Brimacombe, M., Chaaban, J., Zimmerman-Bier, B. & Wagner, G.C. (2008) Autism spectrum disorders: concurrent clinical disorders. J Child Neurol. 2008 Jan;23(1):6-13. View abstract.
  14. Rosenberg, R.E., Kaufmann, W.E., Law, J.K. & Law, P.A. (2011) Parent Report of Community Psychiatric Comorbid Diagnoses in Autism Spectrum Disorders. Autism Res Treat. 2011; 2011: 405849. View abstract.
  15. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Arlington, VA: American Psychiatric Publishing. (Pg. 5-6)
These archived articles were originally published as part of the Interactive Autism Network (IAN) research project. 
The project is closed and no longer accepting participants.

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