A new study by Stanford neuroscientists found that sex and age are strongly tied to which diagnoses tend to co-occur with Autism Spectrum Disorders (ASD). It is widely known that individuals diagnosed with ASD tend to carry a slew of other diagnoses as well. Much of ASD research tends to be focused on the causes of ASD itself, which alludes scientists to date, but this is not particularly helpful for families and providers who are trying to tease apart if their loved one carries an ASD diagnosis, another medical diagnosis, or something else entirely.

In the study, published in the May 2017 volume of Autism Research, the researchers compared data from 4,790 people with Autism Spectrum Disorder and a whopping 1,842,575 without ASD using the Stanford Translational Research Integrated Database Environment (STRIDE), an online database of all cases treated at Stanford University Medical Center from 1995 to the present. It is the largest study to date comparing comorbidities (co-occuring disorders) in ASD and non-ASD populations.

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Findings indicate that epilepsy, attention deficit hyperactivity disorder, central nervous system disorders, and cranial abnormalities tended to occur at surprisingly large frequency in males (over 19% of the male ASD population endorsed), in females (over 15% of the female ASD population endorsed), and in children and adolescents with ASD of both sexes. Although the prevalence of these co-occuring disorders declined people aged, other disorders arose in their place. Older individuals with ASD (defined as over 35 years and above) were found to have increasing diagnoses of schizophrenia. Approximately 25% of adult males with ASD carry a schizophrenia diagnosis while only 7.7% of adult females with ASD also carry a schizophrenia diagnosis. Bowel disorders were also found to co-occur frequently in ASD in childhood and adulthood.

Carefully examining how the results and implications of this study can assist in making more precise ASD diagnoses and in creating increasingly efficacious treatments for ASD across the lifespan. Kaustubh Supekar, a neuroscientist and the study’s first author, answered several questions in an interview about the implications of these findings.

SNB: How do you envision this work evaluating sex & age differences in comorbid conditions in ASD will contribute to the development of more precise diagnostic & treatment methods for ASD?

KS: Diagnosis: More often than not, an individual may present with symptoms that are indicative of ASD, a comorbid condition, both or none. Our study findings provide insights into the likelihood of a condition co-occurring with ASD in a given age-range and gender grouping, and therefore have important implications for such differential diagnosis 

KS: Treatment: Comorbidity patterns reported by our study provide a comprehensive mapping of conditions that are likely to share etiology in males, females, or both, as a function of age.  This map has the potential to not only provide better understanding of the pathophysiology underlying ASD but also inform drug repurposing. For example, our findings suggest that antiepileptic drugs could be more effectively administered to individuals with ASD, particularly children and adolescents with the disorder. 

SNB: Why is this work important for diagnosing medical professionals to be aware of?

KS: Our findings call for a broad range of assessment instruments be made available to clinicians so that they are less likely to miss a diagnosis. For instance, based on our findings, an older male adult (age > 35 y.o.) receiving ASD treatment should also be screened for schizophrenia and the other way around. This would allow for more accurate diagnosis and better treatment.

SNB: How does this work directly impact families with concerns for their ASD (or suspected ASD) family member? 

KS: The results described in our manuscript have the potential to assist families with ASD to better assess disease complexity and allocation of resources based on the expected comorbidity burden. Additionally, it will enable better disease management with proactive screening and subsequent treatment of highly-probable comorbid conditions.

If you are interested in contributing to this type of research, the Stanford Cognitive and Systems Neuroscience Laboratory at Stanford University is recruiting participants between 7 and 12 years old (both typically developing and with ASD or ADHD). You can learn more about their studies here: http://med.stanford.edu/braindevelopment.html


Supekar, K., Iyer, T., & Menon, V. (2017). The influence of sex and age on prevalence rates of comorbid conditions in autism. Autism Research.

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