Autism Comorbidity: Common Co-Occurring Conditions, Diagnosis, and Treatment

Autism comorbidity refers to the presence of one or more co-occurring medical, neurological, or mental health conditions alongside autism spectrum disorder (ASD).

For those living with autism, having comorbidity or multiple comorbidities is often a reality. While percentages vary based on the comorbidity under examination, most individuals with autism are living with at least one comorbidity. For example, studies have shown that people with autism are 2.2 times more likely to have severe headaches.

This high rate of comorbidity in this population can pose serious challenges to these individuals, caregivers, and professionals in the intellectual and developmental disabilities (IDD) field. To help, we’ll discuss some of the most common comorbidities for those with autism and a few of the available treatment options.

What is autism comorbidity?

In the context of ASD, comorbidity describes additional diagnoses — medical, neurological, or mental health — that occur in the same individual. Because these conditions can overlap with autistic traits or add new challenges, they often shape the diagnostic process, guide treatment choices, and affect outcomes over time.

Common co-occurring conditions with autism

ADHD

Attention deficit hyperactivity disorder (ADHD) and autism often co-occur. In fact, studies have found that roughly half of children with autism experience ADHD as a comorbidity.

Researchers have yet to figure out why these two conditions so often coexist. But we do know that they are both neurological conditions that affect the ability to focus, control impulses, manage time, keep organized, and interact socially with others.

Anxiety

Anxiety may be the most common comorbidity for those with autism. Research indicates that up to 84% of autistic individuals also live with anxiety. Elevated levels of anxiety can exacerbate certain complications of autism, such as social withdrawal and repetitive behaviors.

While genetic factors and insufficient supports play a role in the comorbidity of autism and anxiety, experts also point to:

• Language processing abilities: Some people with autism may have difficulty expressing their wants and needs, leading to frustration and anxiety.
• Sensory sensitivity: Enhanced sensitivity to light, sound, taste, and other sensations can prove overwhelming, which can lead to or enhance anxiety.
• Difficulty with social situations: Some autistic individuals have a hard time understanding social cues, which can cause feelings of isolation.
• Task frustration: Some individuals with autism may experience difficulties with motor skills, cognition, and other functions which are used for completing tasks.
• Detail-focused temperament: It’s common for autistic individuals to have hyper-focused attention to detail. This can make changes in routines or shifting focus hard.

Depression

The CDC estimates that 26% of people with autism also have depression. The reasons for this vary.

Some studies point to the attention to detail that many autistic individuals exhibit. These studies argue that this attention to detail can cause individuals to ruminate on an upsetting topic, leading to feelings of depression.

Other research points to difficulty with social interactions as a leading factor.

Epilepsy

Epilepsy is another common comorbidity with autism. Approximately one-in-three individuals with autism are also diagnosed with epilepsy. While the two conditions share genetic markers, researchers do not fully understand why they so often co-occur.

It is common for autistic individuals to have abnormalities detected on an electroencephalography (EEG), with some studies showing that up to 60% of those with autism will show EEG abnormalities. This does not mean that these individuals will experience seizures. Rather, researchers believe it is a secondary symptom of their brain’s physiology which reflects differences in neural pathways among autistic individuals.

Gastrointestinal issues

Research has found that those with autism are four to six times more likely to experience gastrointestinal issues than their neurotypical peers. These issues can present in a variety of ways, the most common being:

• Constipation
• Diarrhea
• Abdominal pain

While the link between gastrointestinal distress and autism remains unclear, one possible cause for this comorbidity could be food selectivity among autistic individuals.

Sleep disorders

Sleep disorders present in individuals with autism far more commonly than their neurotypical peers. Studies have found that sleep issues are twice as common among autistic children than other populations.

The most common sleep disorders among those with autism include:

• Breathing dysregulation, such as sleep apnea
• Insomnia
• Restlessness
• Night walking
• Sleep anxiety

This increased link between autism and sleep disorders could stem from other comorbidities. If an autistic individual is experiencing gastrointestinal distress or anxiety, for example, it can make comfortable sleep much harder to achieve.

Treatment options for those with autism and comorbidity

CBT for individuals with autism and a comorbidity

The comorbidity of autism and depression or anxiety changes how therapists and caregivers approach individual treatment plans. In general, cognitive behavioral therapy (CBT) and non-medication therapies are good first-step solutions for managing the possible presence of a comorbid mental health condition.

Part of the rationale for using CBT to treat comorbid conditions is its versatility. Therapists can successfully incorporate CBT into existing therapeutic sessions, including applied behavior analysis. Furthermore, CBT is based on teaching how irrational thoughts develop. This enables people with autism and comorbid anxiety or depression to stop the thought process before it continues.

Additional strengths of CBT include its long-term usability in managing mental health disorders, usefulness in exposure-based therapies for helping people overcome specific phobias and fears, and low-risk side effects on the mind and body. In children, CBT may be included as part of a treatment plan in the form of role playing as well.

Medication

Medication may be considered as part of a broader, individualized treatment plan—particularly when comorbid conditions such as anxiety, depression, or ADHD significantly impact daily functioning. However, medication decisions should always be made in collaboration with qualified healthcare professionals.

Some of the more commonly prescribed medication types for autism comorbidities include:

• SSRIs for anxiety and depression: While research on antidepressant drugs for anxiety and depression that are comorbid with autism is ongoing, SSRIs have shown good results in reducing anxious depressive thoughts in recent studies.
• Stimulants or non-stimulants for ADHD: Stimulants have proven to reduce hyperactivity among children with ADHD and autism; though it’s less effective than among children with just ADHD.
• Melatonin for sleep disorders: Studies suggest that melatonin reduces the time it takes to fall asleep after getting in bed and increases the total sleep time for those with autism.

After receiving a prescription, individuals and their caregivers or professional care team should continue monitoring their overall mental and physical health. For example, treatment for depression or anxiety may also take several weeks to be effective when medications are used. Medications for mental health, particularly antidepressants, require a person to build up a suitable level of the medication in the body to be effective. As a result, individuals with autism and depression or anxiety should be carefully monitored to ensure they are not a danger to themselves or others until the appropriate serum levels have been reached.

Frequently Asked Questions about autism comorbidity

What is autism comorbidity?

Autism comorbidity refers to the presence of one or more co-occurring medical, neurological, or mental health conditions alongside autism spectrum disorder (ASD). These additional conditions can affect how autism presents and often influence diagnosis, treatment planning, and long-term outcomes.

What are the most common comorbidities with autism?

Common autism comorbidities include attention deficit hyperactivity disorder (ADHD), anxiety disorders, depression, epilepsy, gastrointestinal disorders, and sleep disturbances. Many autistic individuals experience more than one comorbid condition, which can increase the complexity of care.

Why is comorbidity common in individuals with autism?

Autism comorbidity is common due to a combination of genetic, neurological, and environmental factors. Some conditions share underlying biological mechanisms, while others may develop as a result of challenges related to communication, sensory processing, or social interaction. Ongoing research continues to explore these connections.

How does comorbidity affect autism diagnosis?

Comorbid conditions can complicate autism diagnosis because symptoms often overlap. For example, anxiety or ADHD may mask or mimic characteristics of autism, leading to delayed or inaccurate diagnoses. Comprehensive, multidisciplinary evaluations are often necessary to identify all co-occurring conditions.

How does comorbidity impact treatment for autism?

Autism comorbidity requires a coordinated, individualized approach to treatment. Providers may need to address multiple conditions at once using a combination of behavioral therapies, environmental supports, and, in some cases, medication. Effective care plans consider how each condition interacts to affect the individual’s overall functioning and quality of life.