Autism and Co-Occurring Conditions: A Guide

Autism is known to co-occur with several health conditions—but what does this mean? What other diagnoses are most prevalent among autistic individuals, and does an autism diagnosis inform treatment of co-occurring conditions?

Co-occurring health conditions are multiple distinct conditions that are observed in one individual. In medical spaces and scientific literature, these are also often called “comorbidities.” While we often associate the term “morbid” with death, in a medical context, “morbidity” simply refers to a disease or condition, and “comorbid” means medical conditions that occur together. Still, the term “co-occurring” has come into more popular use recently because of the associations that the term “comorbid” carries for many.

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Understanding what conditions regularly co-occur with autism can help autistic people build more holistic pictures of our health, supporting us in understanding which conditions may have a relationship to autism, and perhaps even encouraging us to pursue relevant diagnoses and interventions for untreated symptoms. For co-occurring mental health conditions, and sometimes even physical health conditions, understanding the condition’s intersections with symptoms of autism may inform a more holistic, impactful treatment plan.

Autism is considered a neurodevelopmental disorder, meaning it is characterized by cognitive, behavioral, communication, and motor differences. Other neurodevelopmental disorders can co-occur with some frequency with autism.

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Autism and ADHD

One of the most commonly cited co-occurrences with autism is attention-deficit/hyperactivity disorder (ADHD); between 50 and 70% of autistic people also have ADHD. While autism and ADHD present with distinct symptoms, there is a notable overlap in symptoms between the two conditions, even among individuals who only have autism and not ADHD, or vice versa. These can include sensory differences, executive dysfunction, differences in focus, and emotional dysregulation.

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For those with both autism and ADHD, often called AuDHD, these overlapping experiences and traits can feel heightened. Many AuDHDers also experience conflict between the traits of each diagnosis that compete with each other, such as seeking out novel experiences but confronting anxiety and distress when engaged in them. Autistic and ADHD traits can also converge to create unique experiences, such as a blend of enduring special interests and fleeting hyperfixations, and the frustration that can come with balancing and dedicating time to them.

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Autism and learning disabilities

Learning disabilities can also co-occur with autism spectrum disorder, presenting at a higher rate in autistics than among non-autistics—though this co-occurrence is less well-researched and less well-documented. Learning disabilities are a different kind of neurodevelopmental disorder from autism, and generally affect the way someone learns and understands things. This can include differences in reading and speech (dyslexia), math and numbers (dyscalculia), and writing by hand (dysgraphia).

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Many mental health diagnoses are also more prevalent among autistic individuals than among neurotypical people, notably anxiety and mood disorders. This co-occurrence, at least in part, reflects the many challenges autistic people tend to face and the long-term impact they can have on our wellbeing.

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Autism and anxiety and depression

‍Anxiety and depression are perhaps the most common mental health conditions to co-occur with autism; anxiety has a lifetime prevalence among autistic adults of 42%, and that of depression is 37%.. Autistic people are predisposed to chronic stress because of experiences and traits like social differences, sensory processing differences, difficulty with self-expression, and feeling misunderstood. These challenges can cause feelings of anxiety, sadness, and isolation, and can contribute towards the development of anxiety disorders and depression. Finally, masking and camouflaging, which involve suppression of autistic traits, are also associated with an increased risk of depression and anxiety.

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Autism and social anxiety

Social phobia, also known as social anxiety disorder, is much more common among autistics than neurotypicals. The prevalence of social anxiety among autistic individuals is estimated to be as high as 50%, a staggering figure compared to that of non-autistic people, which is estimated to be between 7 and 13%. For many autistic adults, this may not be a particularly surprising statistic; social anxiety is a natural result of a lifetime of navigating relational difficulties and impossibly opaque social expectations without the social guidebook neurotypicals seem to be born with. The consequences of getting it wrong sting, and set many  of us up for a pattern of anticipatory anxiety in social situations.

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Autism and OCD

Obsessive compulsive disorder (OCD) can also co-occur with autism. Many autistic people also experience symptoms that are similar to those of OCD, such as repetitive and restrictive behaviors and involuntary cognitive loops, without qualifying for a full OCD diagnosis. While this overlap in symptoms has complicated research around the co-occurrence of the two conditions, OCD does seem more prevalent in autistics than in non-autistics. Recent studies also provide evidence of OCD presenting in autistic people with both unique OCD symptoms and OCD symptoms that overlap with those of autism.

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Autism and PTSD

Autistic individuals are also more likely to have a diagnosis of PTSD, associated with acute traumatic events, or complex PTSD (C-PTSD), associated with ongoing traumatic experiences. Autistic nervous systems are less flexible than neurotypical nervous systems; they are more sensitive to adverse events, and more susceptible to trauma. Autistic individuals are also more likely to experience traumatic events than neurotypicals, particularly social traumas like bullying, isolation, and other forms of victimization, which can lead to a complex trauma history for many autistics. Emerging research in children suggests that the types of experiences which can produce lasting trauma may be different for autistic people than for neurotypicals (i.e., persistent sensory stressors).

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Autism and bipolar disorder

Some research also suggests bipolar disorder can co-occur with autism. Bipolar is considered a mood disorder, like depression, and is characterized by alternations between depression and mania or hypomania, or periods of high energy, euphoria, and confidence. The co-occurrence of bipolar disorder with autism is less well-studied than that of other mental health conditions, but its prevalence among autistics has been estimated at 5-7%, compared to 1% among non-autistics.

In addition to mental health conditions, many physical disorders occur in autistic individuals at higher rates than among neurotypical people. Several of these co-occurrences are well-studied, while others require more research to understand their prevalence.

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Autism and gastrointestinal disorders

Gastrointestinal symptoms and disorders are among the most common physical ailments to co-occur with autism. Abdominal pain, constipation, and diarrhea, often associated with irritable bowel syndrome (IBS), make up some of the most frequent GI complaints among autistic individuals. Crohn’s disease and ulcerative colitis, the two kinds of inflammatory bowel disease (IBD), are also more prevalent among autistic people. It is estimated that between 30 and 70% of autistic people have a GI disorder. One study found 36% of autistic participants to have GI disorders, a significant difference from the 21% of non-autistic participants with GI disorders.

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The higher incidence of gastrointestinal disorders among autistic people has received a fair deal of attention, but hasn’t been fully explained. The gut-brain connection is, however, often implicated when exploring these co-occurrences. Also called the gut-brain axis, this connection is a way that the central nervous system and enteric nervous system, responsible for digestion and other gut function, communicate bidirectionally with each other. Ongoing research on the gut-brain axis, especially in autistic people, could unearth more information about why GI symptoms are so prevalent among autistic people.

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Autism and sleep disorders

Sleep disorders also co-occur regularly with autism. Many autistic individuals report taking longer on average to fall asleep than non-autistics, as well as waking up more frequently throughout the night, and overall lower sleep quality.

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There are a few factors that can contribute to sleep differences among autistic people. Many of us experience difficulty “turning off” our brains and winding down for sleep, whether that’s due to relentless, racing, or looping thoughts; anxiety; a need for sensory stimulation; or sensitivity to sensory inputs like any sound or light, or physical sensations like those from sheets or sleep clothes. Autism also correlates strongly with disturbances in the melatonin system, which can affect circadian rhythms and sleep quality.

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Autism and seizure disorders

Seizure disorders also present at a higher rate in autistic people, which is estimated to be between 11 and 39% . Epilepsy is also more common among autistic individuals with intellectual disabilities, occurring at a rate three times higher than in autistics without intellectual disabilities. Research suggests the relationship between autism and seizure disorders is not causal; it seems likely that there is overlap in the environmental and genetic factors that contribute to both conditions. Seizure disorders can present throughout an autistic person’s life—some individuals with autism and epilepsy first experience seizures during childhood, and others in adulthood. 

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Autism and autoimmune disorders

Autistic individuals also experience higher rates of autoimmune dysfunction. Autoimmune disorders such as type 1 diabetes, rheumatoid arthritis, and celiac disease co-occur in autistic individuals at higher rates than they do in neurotypical people. There is also a significant body of research on the connection between parental autoimmune disorders and autism; the likelihood of receiving an autism diagnosis in childhood can be nearly 50% higher among children of parents who have an autoimmune disorder than among those who don’t. Researchers are still investigating the nature of the relationship between autism and autoimmune disorders.

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Autism and other physical conditions

Many other physical health conditions seem to co-occur with autism with some frequency—either from anecdotal data or preliminary studies—but have not been researched in as much depth yet. One is food allergies—though there is very limited data on food allergies in autistic adults, some research suggests that food allergies are more prevalent in autistic children; one study found that the prevalence of food allergies in autistic children was more than double that in neurotypical children. It’s very possible a similar co-occurrence exists among autistic adults and simply hasn’t been studied, as the field of autism research has focused on children for much of its lifetime. As with many conditions that co-occur with autism, we don’t fully understand why allergies are more prevalent among autistics, though there is some reason to believe the gut-brain axis plays a role, since food allergies can affect the gut microbiome. Other physical conditions that appear to co-occur with autism to some degree include migraines, immune dysfunction, some metabolic disorders, and hypermobility spectrum disorders like Ehlers-Danlos syndromes.

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Autistic individuals often require support in medical settings to ensure physicians understand our symptoms and provide appropriate treatment for co-occurring conditions. Autistic people experience differences in communication and sensory processing, including interoception, which refers to perception of internal bodily sensations like pain or hunger. Since many providers lack experience and training caring for autistic patients, these differences can result in medical providers misunderstanding or altogether neglecting symptoms of co-occurring conditions. Increased competency working with autistic patients is an imperative for clinicians; however, absent a healthcare system that is generally responsive to neurodiversity, many autistic people benefit from tools to support their own medical self-advocacy and communication with providers.   

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Understanding the needs and characteristics of autistic patients can also help clinicians provide more tailored, effective treatments for co-occurring conditions.. Often, the standard of care for co-occurring conditions in autistic people is similar to or the same as that for non-autistic people presenting with the same condition. Sometimes, however, interventions for co-occurring conditions in autistic individuals can be improved by making additional considerations around how the condition intersects with autism.

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When it comes to gastrointestinal symptoms and disorders in autistic people, treatment generally looks similar to that of the same conditions in neurotypical individuals. However, since many autistics experience food aversions and restrictive diets, nutritional evaluations can be an important addition to the treatment of GI disorders in autistic patients, in order to identify and address potential nutritional deficits that could be contributing to symptoms.

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For autistics with sleep disorders, many of the same recommendations given to non-autistics around sleep hygiene might be useful to improve sleep quality and duration. These include creating a consistent bedtime routine, reducing screen time before bed, and making sure the bedroom is dark, cool, quiet, and comfortable.

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If hypo- or hypersensitivity or an inability to wind down regularly contribute to an autistic person’s sleep dysfunction, it can help to tackle these symptoms individually with respect to their impact on sleep. This can mean replacing bedding and sleep clothes with ones made from different materials, or removing tags; using a weighted blanket; trying calming practices like meditation and yoga to quiet the mind before bed; or other approaches depending on the individual.

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Understanding the intersection of co-occurring conditions with autism is perhaps most valuable when it comes to treating mental health conditions. Holding together simultaneous diagnoses of autism with other mental health disorders can help an individual parse and process their lived experience more completely, and can help them find truly individualized support.

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Importantly, an autism-affirming therapist will understand how autism can overlap with, interact with, and inform co-occurring mental health conditions. They can work with each individual to provide the right support for their unique experiences.

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Therapists employ a variety of therapeutic approaches; for each individual patient, some approaches work better than others, and many can be supportive for autistic people. Some research suggests cognitive behavioral therapy (CBT), often used with both neurotypical and autistic patients, can be a particularly valuable approach for autistics because of its structured nature and its focus on applying skills in specific contexts rather than generalizing learnings in a top-down way.

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Of course, what works best for each autistic individual will vary person-to-person. It’s best to discuss these approaches one-on-one with a therapist, or even to talk with a few providers to see which approaches work best.

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While there is a somewhat significant body of research around the conditions that most regularly co-occur with autism, there is just as much need for further exploration. Researchers have barely scratched the surface on many common co-occurrences, and others still are widely reported anecdotally, but haven’t been investigated in scientific literature.

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Hopefully, a more widespread understanding of these co-occurrences can help more of us identify symptoms of co-occurring conditions earlier and seek interventions that can improve their quality of life.

With the particularly high rate of co-occurring anxiety, depression, and other mental health disorders that autistics experience, therapy can be one of the most valuable interventions for autistic people to pursue. Prosper Health can match you with a therapist whose approach aligns with what works best for you, and who understands the experiences of autistic adults and can support your individual needs and goals.