Similarities, differences, what to know

Bipolar disorder and autism spectrum disorder share some symptoms and may share some genetic causes. In addition, people with autism are at increased risk for bipolar disorder and vice versa. The two disorders, however, are not the same.

While a link between the two is not well understood, doctors can explore the symptoms and determine if you have bipolar disorder, autism, or both. About 2.8% of the US population is diagnosed with bipolar disorder. About 1.85% of Americans are diagnosed with autism spectrum.

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The link between bipolar disorder and autism

Bipolar disorder and autism are separate diagnoses. However, there are some ways the two disorders can look the same, and it is perfectly possible to diagnose both autism and bipolar disorder.

According to one study, about 7% of people with autism are also bipolar; that’s almost three times the percentage of people in the general population.

Another study found that about 30% of young people diagnosed with bipolar I disorder (in which manic episodes are prolonged or severe) can also be diagnosed with autism spectrum disorder.

Recently, studies have found genetic links between autism and several mental illnesses, including schizophrenia and bipolar disorder; this probably explains some of the crossover symptoms.

In addition to the fact that there are true cross symptoms, there are many symptoms of bipolar that appear in people with more severe autism but for totally different causes. Some of them include hyperactivity, sleep disturbances, impulsivity, restlessness, and irritability.

While it’s reasonable to attribute some of these symptoms to bipolar disorder, it can be very difficult (especially with a non-verbal person) to sort out bipolar and autistic symptoms.

Bipolar disorder vs autism

Since people with autism and people with bipolar disorder can sometimes behave similarly, it can sometimes be difficult to tell the difference. To better understand the similarities and differences between the two disorders, consider:

  • Bipolar disorder is a psychiatric illness, while autism is a neurodevelopmental disorder.
  • To be diagnosed with autism, symptoms must be evident early in the developmental period (before the age of 3).
  • Symptoms of bipolar disorder can appear at any time (and are more likely to appear around age 25).
  • While the criteria for bipolar disorder specifically include mood-related issues such as mania and depression, the criteria for autism are not related to mood.
  • While people with bipolar disorder can switch between extreme moods of mania and depression, people with autism rarely pedal the same way.
  • People with bipolar disorder who are not autistic are unlikely to have autistic symptoms, such as late or disorderly speech or severe problems with social communication.


The causes of these disorders include:

  • Genetic: Autism and bipolar disorder are both genetically related and can be hereditary. However, it is possible that one twin has autism or bipolar disorder while the other twin does not. Research suggests that some of the same genes may be involved in both autism and bipolar disorder (as well as other mental and developmental disorders).
  • Problems during pregnancy: Autism can result from a mother’s exposure to specific drugs during pregnancy (eg valproic acid). Autism is also more likely if a baby is born prematurely or if the parents are older (although it’s not clear why these are risk factors). Bipolar disorder does not appear to be caused by these problems.
  • Environmental problems: Episodes of bipolar disorder can be triggered by a stressful event such as death or divorce. This is not the case with autism.
  • Structure of the brain and function: Some evidence suggests that the brains of people with autism and bipolar disorder are slightly different from typical brains, but in somewhat different ways.

Signs and symptoms

Depending on the individual, the signs and symptoms of autism and bipolar disorder may be similar. For example, people with both disorders may have:

  • Irritability
  • Sleep disturbed
  • Repetitive behavior
  • Distractibility and impulsivity
  • Loud, fast and virtually uninterrupted speech
  • Impulsiveness which can lead to aggression

These behaviors, however, occur for very different reasons, and there are distinct symptoms that exist only in autism and only in bipolar disorder.

If you are concerned that your child with autism may be bipolar, you should contact your doctor, but also keep in mind that:

  • Autism is not a cyclical disorder. You shouldn’t see sudden, severe mood swings happening for no apparent reason.
  • Autism cannot be “triggered” by an event. Symptoms should appear before the age of 3, and although autistic symptoms may improve, you won’t see a time when they “go away.”
  • Autism, on its own, shouldn’t cause severe depression or suicidal thoughts (although people with autism may feel depressed, like everyone else, when circumstances are depressing).
  • People with autism are likely to have moderate to extreme difficulties with speech, social communication, awareness of the needs and feelings of others, and may have significant sensory problems. These are not necessarily symptoms of bipolar disorder.
  • Stimming (rocking, pacing, mumbling, etc.) is common with autism and is a self-calming tool. If it’s present consistently for a long time, it’s probably not related to bipolar disorder.


Autism is usually diagnosed in early childhood, although highly functional individuals can be diagnosed in adolescence or adulthood. Autism is usually diagnosed through observations and specific tests and questionnaires, as there is no biomarker for the disorder. Diagnosticians are looking for:

  • Specific behavioral differences typical of autism (stimming, lack of eye contact, etc.)
  • Delayed speech or peculiarities such as echolalia (repetition of the same sentences or “echo” on television or movies)
  • Sensory dysfunction
  • Social and communication delays and disturbances

Bipolar disorder is rarely diagnosed in toddlers. The diagnostic process often begins with a physical exam and lab tests to rule out other problems such as thyroid issues that can cause mood swings. The patient must have had at least one episode of mania.

Like autism, bipolar disorder does not have a biological marker, so physical tests can only rule out other problems.


Treatment for autism may or may not include pharmaceuticals. Typically, autism is treated with therapies such as applied behavior analysis, developmental and play therapies, speech therapy, and social skills training. When pharmaceuticals are used, they often include second-generation anxiolytics and antipsychotics.

Treatment for bipolar disorder is more likely to include specific mood stabilizers such as lithium. Second-generation antipsychotics and antidepressants can also be used. Additionally, cognitive therapy (talk therapy) is often helpful for people with bipolar disorder.

When to seek professional treatment

If you are concerned that your young child has autism or bipolar disorder, your first step should include a visit to the pediatrician. Describe your child’s symptoms and request that your child be evaluated for these disorders.

Make sure the person or team performing the assessment has a solid background in both disorders, as it is easy to confuse one with the other or miss signs of mental illness in a child with autism.

Adults seeking diagnosis and treatment should carefully document symptoms, paying particular attention to the following questions:

  • How long have these symptoms been present? (If they’ve happened suddenly, they’re almost certainly unrelated to autism.)
  • Have there been cycling episodes of mania and depression? When, how often and for how long? (This may suggest bipolar disorder).
  • Does the individual have suicidal thoughts? (Although such thoughts occur in both disorders, they are more likely to appear in someone with bipolar disorder.)
  • Does the individual have difficulties with social communication, symptoms of sensory dysfunction (problems with bright light and loud noises, for example) or delays in speaking? (Although some of these symptoms occur in both disorders, if they are all present, they may suggest autism.)


Bipolar disorder and autism spectrum disorder are not the same. However, they do have some symptoms in common and may also share some underlying genetic risk factors. People with autism are at increased risk for bipolar disorder and vice versa.

Symptoms, age of onset, diagnostic criteria, and treatment methods are different for the two disorders. Children should be screened for autism and any concerns raised with the child’s pediatrician to get a proper diagnosis. Adults should seek professional diagnosis.

A word from Verywell

Autism and bipolar disorder can appear in the same person, but the diagnosis can be tricky. This is especially difficult when the person with autism does not have the verbal skills to describe their emotional ups and downs.

For this reason, it is important to find a highly experienced diagnostician to assess a person’s symptoms. If you are uncomfortable with the diagnosis or have further questions, it is a good idea to seek a second opinion.

Treatments that work for a disorder can be ineffective or even harmful when applied inappropriately.

Frequently Asked Questions

  • What is the difference between autism and bipolar disorder?

    Autism is a developmental disorder; symptoms should appear before the age of three. Bipolar disorder is a mental illness that can appear at any age and can be “triggered” by traumatic emotions.

  • Can Autism Be Confused With Bipolar Disorder?

    Yes. Some of the behaviors seen in autism (such as fast speaking, pacing, and irritability) are also present in bipolar disorder. However, these symptoms appear for different reasons.

  • Is bipolar disorder part of the autism spectrum?

    No. Bipolar disorder is not on the autism spectrum, although an unusually high number of people with bipolar disorder also have autism (and vice versa).

About Margie Peters

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