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Arnett Lab | Caregiver and Child Resources | Overview

The goal of our video blog is to summarize ADHD-related research and discuss implications for day-to-day care of children with ADHD. We hope that you find the content in our videos to be entertaining and helpful! Thank you!

-The Arnett Lab

Latest Episode

Episode 6: Answers through ADHD Research: Comorbidity in ADHD 


Comorbidity is when a child or adolescent meets criteria for more than one disorder. A national study found that approximately 50% of children with ADHD meet criteria for an additional disorder. Some of the most common symptoms and comorbid diagnoses that children with ADHD experience are anxiety, depression, behavioral disorders like oppositional defiance, and learning disorders like dyslexia.

In a twin study published by Erik Willcutt and colleagues (2007), these researchers showed that genes that contribute to ADHD also contribute to dyslexia; these “shared genetic factors” are found for other comorbidities as well. Another reason for comorbidity in ADHD is that ADHD is a disorder of dysregulation, and this includes dysregulated emotions as well as dysregulated attention and behavior. A study by Tracey Tsang (2015) found that children with ADHD who also have a coexisting disorder tend to have more severe ADHD symptoms and more functional impairment, indicating that increased dysregulation seems to affect children across multiple symptom domains. Finally, sometimes coexisting disorders are secondary to the ADHD symptoms themselves. For example, a child with ADHD may have more difficulty in school, and therefore experience stress or low self-esteem due to their ADHD diagnosis.

Families can support their children at home by carefully monitoring coexisting symptoms and consulting with a child psychologist if these additional symptoms interfere with the child’s functioning. Oftentimes, behavioral, or pharmacological treatment for ADHD can also improve coexisting symptoms. However, if the additional symptoms do not get better, we recommend seeking evidence-based treatment for that coexisting condition.


Biederman, J., Monuteaux, M. C., Spencer, T., Wilens, T. E., & Faraone, S. V. (2009). Do stimulants protect against psychiatric disorders in youth with ADHD? A 10-year follow-up study. Pediatrics, 124(1), 71-78.

Larson, K., Russ, S. A., Kahn, R. S., & Halfon, N. (2011). Patterns of comorbidity, functioning, and service use for US children with ADHD, 2007. Pediatrics, 127(3), 462-470.

Reimherr, F. W., Marchant, B. K., Gift, T. E., & Steans, T. A. (2017). ADHD and anxiety: clinical significance and treatment implications. Current psychiatry reports, 19(12), 1-10.

Shapero, B. G., Gibb, B. E., Archibald, A., Wilens, T. E., Fava, M., & Hirshfeld-Becker, D. R. (2021). Risk factors for depression in adolescents with ADHD: the impact of cognitive biases and stress. Journal of Attention Disorders, 25(3), 340-354.

Song, M., Dieckmann, N. F., & Nigg, J. T. (2019). Addressing discrepancies between ADHD prevalence and case identification estimates among US children utilizing NSCH 2007-2012. Journal of Attention Disorders, 23(14), 1691-1702.

Tsang, T. W., Kohn, M. R., Efron, D., Clarke, S. D., Clark, C. R., Lamb, C., & Williams, L. M. (2015). Anxiety in Young People With ADHD: Clinical and Self-Report Outcomes. Journal of Attention Disorders, 19(1), 18–26.

Uchida, M., Spencer, T. J., Faraone, S. V., & Biederman, J. (2018). Adult outcome of ADHD: an overview of results from the MGH longitudinal family studies of pediatrically and psychiatrically referred youth with and without ADHD of both sexes. Journal of attention disorders, 22(6), 523-534.

Willcutt, E. G., Pennington, B. F., Olson, R. K., & DeFries, J. C. (2007). Understanding comorbidity: A twin study of reading disability and attention-deficit/hyperactivity disorder. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics, 144(6), 709-714.