What they are and what they look like

Comorbidity occurs when two or more conditions or disorders are present in the same individual. On average, around three quarters of individuals diagnosed with ASD have at least one comorbid condition. Attention deficit/hyperactivity disorder (AD/HD), anxiety, and depression are the most prevalent comorbidities among individuals on the spectrum.1,2 Gastrointestinal issues and epilepsy, among others, are also frequently identified.3

Comorbidities can be difficult to diagnose and can make diagnosing ASD equally as challenging. Therefore, it is important to understand what comorbidities are and what they look like. To help you get started, listed below are the most prevalent co-occurring conditions for individuals with ASD. A short list of “red flags” to keep watch for are provided, along with links to helpful resources and more information:


On average, between 50-60% of children with ASD are diagnosed with comorbid anxiety.4,1 Anxiety can take many forms and can be difficult to spot in individuals on the spectrum as there is significant symptom overlap with common characteristics of ASD, like stimming and obsessive behaviors. Some red flags to look for are:

  • Disrupted sleeping patterns/ trouble sleeping
  • Avoiding social situations
  • Become more dependent on schedules and routines
  • Increased meltdowns (in number or intensity)
  • Self-injurious actions (i.e., scratching, head-banging, biting, etc.)
  • Increased stimming (more often or more intense)
  • Sweaty palms
  • Increased heart rate5

Anxiety can be medically diagnosed, and an array of treatment options are available. Anti-anxiety medications are attainable with diagnosis and there are several cognitive behavioral therapy programs that have been adjusted for individuals on the spectrum dealing with anxiety.4


Individuals with ASD are four times more likely to be diagnosed with clinical depression during their lifetime than their neurotypical counterparts.7 The causes for the increased probability are hard to pinpoint, and though many theories are being tested, more research is needed.8 Some red flags to look for include: 

  • Loss of interest in favorite activities or topics
  • Chronic sadness and/or fatigue
  • Noticeably worse hygiene habits
  • Significant weight changes
  • Increasingly seeking isolation
  • Trouble concentrating and/or sleeping
  • Chronic feelings of hopelessness, irritability, or guilt
  • Increased indecisiveness9

Depression can be a profoundly serious illness, especially for children and adults with ASD. On average, individuals on the spectrum struggle more with suicidal tendencies and thoughts than the general population.10

If you or a loved one with ASD are experiencing any of these symptoms, please speak to your doctor. You are not alone and there are several therapies and medications that can help ease the hardship of depression. 

If you need help today, please call a helpline (24/7):

Attention deficit/hyperactivity disorder (AD/HD)

Studies have shown the prevalence of AD/HD in autistic individuals ranges from 14-78%. Effects of AD/HD are generally more intense for children with ASD, especially in social settings.11 Individuals with AD/HD exhibit the following trait(s):

  • Continued inability to pay attention
  • Problems with time management
  • Difficulty remembering things
  • Issues with organized tasks and hyperactivity8

AD/HD symptoms overlap substantially with those of ASD, so it can be especially difficult to diagnose. If you think you or your child may have AD/HD, it is best to see a specialist for an assessment. Ensure the specialist is familiar with ASD and AD/HD. Consult your medical provider to create a tailored treatment if you receive a diagnosis.12,8

Gastrointestinal Issues (GI)

Children on the spectrum are up to eight times more likely to have gastrointestinal issues than their non-ASD counterparts.13,3 Gastrointestinal issues/diseases have been linked to ASD symptom severity and pathogenesis. However, it is unclear why GI issues co-occur with ASD so frequently.14,15 If you or your child with ASD are experiencing any of the following symptoms, you may be having GI issues.3,12

  • Chronic constipation
  • Chronic diarrhea
  • Abdominal pain
  • Oesophageal reflux (acid reflux)

Treatments for GI issues should be specific to you and your family. Talk to your doctor before trying any special diets or supplements. 


Epilepsy is a brain disorder that causes seizures and affects almost one-third of individuals diagnosed with ASD.16 Family members of individuals with ASD are more prone to having epilepsy and vice-versa.17 Seizures are most common in young children and teenagers and occur more often in individuals with ASD and individuals with: (a) moderate/severe intellectual disabilities or (b) another neurological condition (e.g., cerebral palsy).12 Red flags include: 

  • Severe headaches
  • Long staring spells with no explanation 
  • Involuntary movements 
  • Unexplained confusion 

Less visible symptoms:

  • Sleepiness
  • Changes in abilities or emotions without explanation
  • Disrupted sleep patterns8

If you think you or your child with ASD may have epilepsy, talk to your doctor and consult a neurologist. Epilepsy usually involves medication and should be treated quickly to prevent brain damage.3,12,16

More information and resources:

End Notes

[1] Research in Autism Spectrum Disorders, 7;12, pages 1595-1616, (2013)
[2] Review Journal of Autism and Developmental Disorders, 1;2, pages 124-134, (2014)
[3] Autism Speaks, Medical conditions associated with autism
[4] Research in Autism Spectrum Disorders, 6;1, pages 406-412, (2012)
[5] Anxiety: autistic children and teenagers, raisingchildren.net.au
[6] Journal of Child Psychology and Psychiatry, 50;3, pages 224-234, (2009)
[7] Journal of Abnormal Child Psychology, 47, pages 165-175, (2018)
[8] Spectrum Deep Dive, The deep emotional ties between depression and autism
[9] Beyond Blue, Signs and symptoms of depression
[10] Current Developmental Disorder Reports, 5, pages 65-76, (2018)
[11] Neuroscience and Behavioral Reviews, 35;5, pages 1081-1088, (2010)
[12] Comorbidity and Autism Spectrum Disorder, raisingchildren.net.au
[13] Journal of Autism and Developmental Disorders, 44;5, pages 1117-1127, (2014)
[14] Harvard Review of Psychiatry, 22, pages 104-111 (2014)
[15] National Reviews Neuroscience, 12(8), pages 453-66 (2011)
[16] Centers for Disease Control and Prevention, Epilepsy fast facts
[17] Neurology, 87;2, pages 192-197, (2016)

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