Bipolar disorder is a brain disorder characterized by changes in energy levels, mood, and functioning. Autism spectrum disorder (ASD) is a developmental brain disorder that impacts behavior and communication.

Research indicates that people with bipolar disorder and ASD share some of the same gene expression patterns. Additionally, autistic people can experience symptoms associated with bipolar disorder, and potentially vice versa.

That said, little is known about the true prevalence of ASD and bipolar disorder together, or how they relate. Symptoms of both conditions overlap, increasing the risk of misdiagnosis. Existing prevalence estimates are therefore likely exaggerated.

This article discusses the possible links between ASD and bipolar disorder. It also looks at diagnosis, misdiagnosis, and symptom breakdowns for each condition.

Smiling child plays video games.Share on Pinterest
blackCAT/Getty Images

One study found that as many as 30% of autistic people also have symptoms of bipolar disorder. The same study also found that bipolar disorder, generally speaking, also manifested earlier in autistic people.

But researchers do not really know how common it is to have both ASD and bipolar disorder. It is also unclear whether there are any factors or triggers that increase the risk of experiencing ASD and bipolar disorder.

ASD and bipolar disorder do appear to share specific genetic expression patterns in the brain.

Bipolar disorder, ASD, and schizophrenia all seem to activate certain genes in astrocytes, which are star-shaped brain cells that perform many essential functions in the central nervous system. All three conditions also seem to suppress genes that help synapses (the junctions between nerve cells) work properly.

Some research also indicates that young adults with ASD and bipolar disorder are more likely to:

  • experience mood symptoms earlier
  • be easily distracted
  • have racing thoughts
  • have a depressed mood
  • be socially withdrawn

Doctors sometimes mistakenly diagnose autistic people with bipolar disorder because both conditions share some similar behavioral differences.

Overlapping behavioral differences between ASD and bipolar disorder include:

  • elevated or depressed mood
  • intense irritability
  • aggression
  • excessive talking
  • distractibility
  • a tendency to “get in trouble” or do risky things
  • repetitive activities or behaviors, such as pacing
  • sleep disturbances
  • being accident-prone
  • racing thoughts or trouble organizing thoughts

It can also be difficult to diagnose mental health conditions in autistic people who have significant communication or intellectual impairments.

Diagnosing ASD

To diagnose ASD, a doctor will perform a general developmental screening during routine well-child checkups at 9, 19, 24, and 30 months. Most doctors screen specifically for autism during 18- and 24-month visits. A doctor may perform additional screening if a child has risk factors for ASD.

A doctor will also ask parents questions about the child’s behavior and activities and combine them with their screening findings. If a child may have ASD, they will be referred to a second evaluation with a team of doctors that may include:

  • developmental pediatricians
  • child psychologists or psychiatrists
  • speech-language pathologists who recognize communication problems
  • neuropsychologists

A doctor may also run other tests to rule out other conditions, such as a hearing test or blood tests.

Other challenges

To diagnose bipolar disorder, a doctor will ask questions about potential mood episodes, their severity, and how long they lasted. A psychiatrist will usually ask questions about feelings, thoughts, and experiences. Autistic people who have trouble communicating or expressing themselves often have trouble describing their feelings, thoughts, and experiences.

To properly determine whether someone has ASD, bipolar disorder, or both, a doctor will often need to assess when symptoms occur, how long they last, their severity, and whether they make sense in context.

For example, talking too much or easily losing focus occasionally is normal for most people, especially people with ASD. But someone who is suddenly high-energy, acts inappropriately, and goes for days on end without sleep may be experiencing a manic episode.

There are numerous other noteworthy similarities and differences between the two conditions in terms of symptoms, management, and treatment.

Symptoms of bipolar disorder

People with bipolar disorder usually experience periods of high energy and mood (mania) and low energy and mood (depression).

Many people with bipolar disorder spend a few weeks to months in one of these mood periods before gradually transitioning to the opposite period. A lot of people have neutral periods in between these two opposing mood episodes. But some people rapidly alternate between these periods, in a process called rapid cycling.

Bipolar disorder causes different symptoms depending on which mood state a person is experiencing. Many people occasionally feel mild versions of symptoms associated with mania and depression. But people with bipolar disorder experience these symptoms to the extreme.

Symptoms associated with mania:

  • feeling energized despite a reduced desire and ability to sleep
  • having rapidly changing ideas, uncontrollable racing thoughts, or quickly changing topics when speaking
  • feeling invincible or on top of the world
  • increased activity levels, engagement, or restlessness or working on multiple projects simultaneously
  • pressured (increased or faster than usual) speech
  • reduced inhibition, such as engaging in risky behaviors
  • hallucinations (less common)

Symptoms associated with depression include:

  • reduced or lost interest in activities previously enjoyed
  • unexplained exhaustion
  • feeling intensely, overwhelmingly sad, hopeless, worthless, or guilty
  • sleeping and eating more often or less often than normal
  • trouble concentrating
  • thoughts of suicide and death

Causes of bipolar disorder

Bipolar disorder seems to be primarily a genetic disorder that appears to cause abnormal imbalances of brain chemicals, leading to deregulated brain activity. Some 80–90% of people with bipolar disorder have a family member who also has it.

A few factors may also increase the risk of developing bipolar disorder if someone is vulnerable to it genetically, such as:

  • extreme stress
  • grief
  • trauma
  • alcohol or drug use
  • certain medications, especially antidepressants
  • sleeping problems or disturbances

Treatment and management of bipolar disorder

Everyone’s treatment plan for bipolar disorder varies depending on their symptoms and other factors.

But most doctors prescribe a combination of cognitive behavioral therapy, mood-stabilizing medications, and antidepressants to treat bipolar disorder. They may also prescribe antipsychotic medications and electroconvulsive therapy.

Symptoms, or differences, in autistic people

Experts consider autism to be a spectrum disorder because there is such a large variation in the differences people experience and their severity. The American Psychiatric Association diagnose ASD by looking at these potential differences:

  • repetitive behaviors
  • restricted interests in the external environment
  • trouble interacting and communicating with others
  • symptoms that impact someone’s ability to function normally
  • trouble making or maintaining eye contact
  • long lasting, intense interest in special topics
  • reacting negatively to changes in routine

Causes of ASD

Researchers are still uncovering the true cause of ASD. That said, at present, it seems that ASD develops due to a combination of genes and environmental influences.

Some factors appear to increase the risk of developing ASD, such as:

  • having older parents
  • having a very low birth weight
  • having siblings with ASD
  • some genetic conditions, such as Rett syndrome, fragile X syndrome, and Down syndrome

Treatment and management of ASD

People with ASD typically manage their condition with a mixture of psychological, behavioral, and educational therapy, medications, and special resources and programming.

Lithium carries a risk of toxicity, so doctors may have autistic people and people with bipolar disorder try other medications first. Symptoms of autism may make it harder to notice the signs of toxicity.

Parents or caregivers who notice a child may be developing slower, or differently, than expected should talk with a doctor.

If children have trouble adjusting to, or engaging with, daily activities or demonstrate other symptoms or differences in behavior that impact behavior or communication, it is advisable to contact a doctor.

People who think they may be experiencing symptoms of mania or depression should also talk with a doctor as soon as possible.

Getting early, proper treatment typically reduces the risk of negative complications and increases the chance someone can live a normal life.

ASD and bipolar disorder seem to cause similar gene expression patterns in the brain. For this reason, misdiagnosis does occur at times.

It remains unclear how the two conditions truly relate to each other. It is also unclear how many people truly have both autism and bipolar disorder because of the rate of misdiagnoses.

Getting the correct treatment early on typically reduces the risk of negative complications associated with both bipolar disorder and ASD. It increases the chance that someone can live a normal, productive life.

People concerned that they or someone close to them may have either condition should contact a doctor for a complete diagnosis.