Eilis O’Connell MA, BCBA, LBA-NY
Association for Science in Autism Treatment

The Association for Science in Autism Treatment (ASAT) provides high quality, accurate, and timely resources for individuals on the autism spectrum, their families, and the professionals who work with them. Our organization upholds the value that all individuals should have knowledge and access to information with extensive scientific support regarding the effectiveness of treatments. While we mainly focus on the autism community, it is important to provide families with organizations that support an evidence-based approach to treatment for varying communities in need of facts and scientific resources.

ASAT recognizes that individuals with autism often have comorbid diagnoses that require additional intervention, resources, and support. Studies have found that certain co-occurring conditions are common in children with autism; and a diagnosis of autism and any co-occurring conditions are imperative for specific and effective treatment (Leyfer et al., 2006). The following diagnoses can accompany autism spectrum disorder (ASD): Down syndrome, cerebral palsy, attention deficit hyperactivity disorder (ADHD), obsessive compulsive disorder (OCD), epilepsy, and varying mental illnesses (i.e., depression, anxiety, etc.). The Diagnostic and Statistical Manual of Mental Disorders (DSM-5), created by the American Psychiatric Association (2013), provides criteria for the full array of psychiatric diagnoses. In some instances, a person can fulfill criteria across multiple diagnoses leading to a comorbid diagnosis. Additional conditions can manifest at birth and be diagnosed by your licensed medical physician (Hyman et al., 2020). Other diagnoses may not manifest until later in childhood with behavioral and/or medical symptoms that should be reported to your child’s pediatrician, who may refer to a specialist. The American Academy of Pediatrics (AAP) recommends regular screenings for emotional/behavioral conditions with your pediatrician (Hyman et al., 2020).

Across the lifespan of these various conditions, it is imperative that individuals and their families are able to find organizations that provide them with supports that are effective and scientifically sound. Multiple diagnoses bring a greater sea of varying needs and possible interventions that families must examine for both suitability and effectiveness. Choosing which intervention works best for your child with comorbid diagnoses will be an individualized process that centers around your child’s unique needs. It may be helpful to consider the following when speaking with professionals:

  • Research information from established organizations and reach out to professionals who specialize in each diagnosis.
  • Consider existing research carefully. Interventions with research to support their effectiveness may vary according to diagnosis. Comorbid diagnoses can result in unique needs for which there may be a limited research basis. Further, interventions that are proven effective for those with one diagnosis may have a limited basis for multiple diagnoses and may not be a suitable intervention.
  • Communicate with the educational and medical professionals that serve your child to ensure that your child’s distinctive needs are known; and that those needs are being met with the most up-to-date, evidence-based interventions, tailored specifically for them.
  • With multiple diagnoses, you may have a number of professionals from various disciplines serving your child and family; therefore, advocate for a multidisciplinary approach to ensure that the team is working cohesively and communicating effectively, so that there is more agreement on “what works” for your child to help them reach their goals.
  • In the school setting, students with Individualized Education Programs (IEPs) receive a triennial review to see if the child’s needs have changed and if other special education services and accommodations are needed. Although parents can raise concerns at any point, this is an important opportunity to share new diagnoses for the education team to consider additional needs. Invite to the meeting any professionals working with your child to ensure they can support the team in best practices for a particular need.

Below is a list of organizations that support evidence-based resources for the aforementioned diagnoses that may accompany autism. We selected these given the higher rates of comorbidity with these diagnoses and conditions amongst individuals with ASD.

Attention Deficit Hyperactivity Disorder

Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder that can impact an individual across the lifespan, including difficulty in paying attention, higher levels of activity, and difficulty in controlling one’s impulses (Center for Disease Control [CDC], 2021). It has been found that 31% of children with autism also meet criteria for an ADHD diagnosis (Leyfer et al., 2006). The National Resource Center on ADHD provides a variety of resources for individuals with ADHD, their families, and professionals that work with the population. Information on advocacy efforts, publications, toolkits for parents and caregivers, information libraries, and more provide a plethora of guidance for individuals with ADHD and those supporting them.

Cerebral Palsy

Cerebral palsy is a group of disorders that affects a person’s ability to move due to brain damage during pregnancy or shortly after birth (CDC, 2020). Cerebral palsy can manifest in different ways, affecting a person’s muscle control, movement, posture, balance, coordination, and reflexes. Cerebral palsy may co-occur with intellectual, visual, hearing, and speech impairments (CDC, 2020). The Cerebral Palsy Alliance is a research association that focuses on funding research solely about cerebral palsy. The website discusses current and past research projects related to early detection and intervention, chronic pain, technology, regenerative medicine, and genomics. There is also a section reviewing the causes, types, and facts surrounding cerebral palsy. The news page is a helpful resource reviewing a variety of topics in article form for individuals and their families.

Down Syndrome

Down syndrome is a condition in which a person has an extra copy of a chromosome, also known as Trisomy 21, resulting in physical and intellectual differences. The impact of Down syndrome varies across individuals but may result in common physical features and an IQ within the mildly-to-moderately low range (CDC, 2014). The National Down Syndrome Society (NDSS) is a human rights organization that focuses on resources and supports, policies and advocacy, and community engagement. The website provides resources across the lifespan, including local supports and a helpline. You can sign up for their monthly newsletter to stay up to date on the organization’s initiatives and activities. Specifically, they provide an article about the dual diagnosis of autism and Down syndrome. For greater insight and information into research initiatives for individuals with Down syndrome the Down Syndrome Education International (DSE) is a helpful site. DSE lists past and current research across the globe, along with resources of evidence-based teaching materials and trainings with online courses.


Epilepsy is a neurological disorder that results in unpredictable seizures that can affect a person across the lifespan. Epilepsy is a spectrum disorder with a range of seizure types and can potentially lead to other health problems (Epilepsy Foundation, 2014). Children with autism that have intellectual disability, are female, or who are born at lower gestational age are at greater risk of developing epilepsy (Hyman et al., 2020). The Epilepsy Foundation is an organization that provides a variety of educational and program resources for individuals living with epilepsy, and their families. The organization has links to local chapters of the foundation on their website. They provide information and guidance on advocacy actions, such as the promotion of research to gain a better understanding of epilepsy. Important resources for the community at large include a “toolbox” that has resources to help people manage their epilepsy, seizure first aid and safety, information for school preparedness, and more.

Mental Illness

Mental illness refers to a wide range of mental health disorders that impact a person’s mood, thinking, and behavior (Mayo Clinic, 2019). Mental illness can include but is not limited to depression, anxiety disorders, and schizophrenia. Signs and symptoms vary for the specific mental illness and can be identified by a trained psychologist and/or psychiatrist. Leyer et al. (2006) reported that 10% of children with autism have had at least one major depressive episode. It has been found that cognitive therapy and medications are successful interventions for depression (Hyman et al., 2020). The National Alliance on Mental Illness is an organization with a comprehensive list of resources for individuals with mental illness to navigate areas of need including health insurance, what to do in a crisis, and support in personal and work life. The website also has a link to local support groups you can find in your area and a video resource library. Advocacy efforts you can be involved in are listed, along with the ability to sign up for a digital newsletter.

Obsessive Compulsive Disorder

Obsessive compulsive disorder (OCD) is a mental health disorder in which a person has cycles of obsessions that can include unwanted thoughts, intrusive images and/or urges that result in compulsions, which leads an individual to engage in certain behaviors to “get rid” of the obsessions and their resulting feelings (International OCD Foundation, 2021). Leyfer and colleagues (2006) found that 37% of children with autism have a comorbid diagnosis of OCD. Behavioral approaches are first recommended for the treatment of OCD. Cognitive behavioral therapy has demonstrated the greatest effectiveness but may be less effective for individuals with ASD and OCD (Hyman et al., 2020). The International OCD Foundation aims to fight stigmas associated with OCD, increase effective research and access to treatment, and support individuals affected by OCD, along with the professionals who treat them. The website provides a “Find Help” section where a person can find local therapists, support groups, and programs. Resources are separated for different populations, such as children. You can sign up for a quarterly newsletter and access the archived ones on the website. The International OCD Foundation also provides a plethora of resources for professionals, including applications for grants and conferences.

We hope you find the above descriptions useful in your journey to learn more about diagnoses and conditions that sometimes occur along with ASD. The following professional organizations can provide additional resources, including referrals to families:

Association for Behavioral and Cognitive Therapies (ABCT)

ABCT is a multidisciplinary organization that works to enhance the treatment of various human conditions through the use of cognitive, behavioral, and biological evidence-based principles. Diagnoses such as depression, anxiety, and OCD have research to support the use of Cognitive Behavioral Therapy (CBT) as a treatment. The organization’s website provides resources for numerous diagnoses including but not limited to ADHD, child mood disorders, OCD, and ASD. ABCT provides a fact sheet exploring what to expect from therapy and discusses the different types of therapy, such as psychotherapy and CBT. The website also contains a helpful page to locate CBT therapists near your area and has options to select specialties related to specific diagnoses.

Behavior Analysis Certification Board (BACB)

The BACB is an organization that certifies professionals delivering ABA services including Board Certified Behavior Analysts (BCBAs) and Registered Behavior Technicians (RBTs). They are the governing board for credentialed professional utilizing behavior analysis, and ensure these professionals adhere to an ethical code. On this website you can find a directory of BCBAs within your area. The BACB also provides fact sheets and videos explaining what behavior analysis is and the subspecialities in which BCBAs can specialize.

Society of Clinical Child and Adolescent Psychology (SCCAP)

SCCAP is an organization that created the “Effective Child Therapy” initiative to ensure caregivers have easy to access, comprehensive information related to mental health and behavioral concerns in children and adolescents. An emphasis is placed on treatments with strong scientific backing of their effectiveness. The site contains a section exploring several evidence-based therapies including descriptions of different forms of CBT, interpersonal psychotherapy for depression, and organizational skills training for ADHD. A helpful document is provided that describes the level of research support for each therapy that is listed on the website to support caregiver’s discernment. The website contains a plethora of resources for families including a page on how to know if therapy is working, a parent site of videos from mental health experts, and a tips and tools page.

We hope the listed resources prove supportive and provide individuals with evidence-based information about varying comorbid diagnoses. With any potential intervention, systematic and applied research is still needed to determine the external validity of these treatments for individuals with autism and an accompanying disorder. Seek out the advice of a trusted medical provider and/or psychologist to ensure effective treatment is chosen. Many times, potential interventions suggested may require modifications that can be done mindfully with the support of your multidisciplinary team.


American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). https://doi.org/10.1176/appi.books.9780890425596

Center for Disease Control and Prevention (2020, December 28). Facts about Down syndrome.

Center for Disease Control and Prevention (2021, January 26). Attention deficit/hyperactivity disorder (ADHD). https://www.cdc.gov/ncbddd/adhd/index.html

Center for Disease Control and Prevention (2020, December 31). What is Cerebral Palsy?

Epilepsy Foundation (2014, January 21). What is Epilepsy? https://www.epilepsy.com/learn/about-epilepsy-basics/what-epilepsy

Hyman, S. L., Levy, S. E., & Myers, S. M. (2020). Identification, evaluation, and management of children with autism spectrum disorder. Pediatrics, 145(1), https://doi.org/10.1542/peds.2019-3447

International OCD Foundation (2021). What is OCD? https://iocdf.org/about-ocd/

Leyfer, O. T., Folstein, S. E., Bacalman, S., Davis, N. O., Dinh, E., Morgan, J., Tager-Flusberg, H., & Lainhart, J. E. (2006). Comorbid psychiatric disorders in children with autism: Interview development and rates of disorders. Journal of Autism and Developmental Disabilities, 36(7), 849-861. https://doi.org/10.1007/s10803-006-0123-0

Mayo Health Clinical (2019, June 8). Mental illness. https://www.mayoclinic.org/diseases-conditions/mental-illness/symptoms-causes/syc-20374968

Citation for this article:

O’Connell, E. (2021). Comorbidity in autism: A review of related organizations. Science in Autism Treatment, 18(6).

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