The Connection Between Bipolar and Autism: 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 connection between the two is not well understood, doctors can explore symptoms and determine whether you have bipolar disorder, autism, or both. About 2.8% of the U.S. population is diagnosed with bipolar disorder. About 1.85% of Americans have an autism spectrum diagnosis.

The Connection Between Bipolar Disorder and Autism

Bipolar disorder and autism are distinct diagnoses. There are, however, some ways in which the two disorders can look similar, and it is perfectly possible to be diagnosed with both autism and bipolar disorder.

According to one study, about 7% of people with autism are also bipolar; this is nearly three times the percentage of people in the general population.

Another study found about 30% of youth diagnosed with bipolar I disorder (in which manic episodes are prolonged or severe) are also diagnosable with autism spectrum disorder.

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

In addition to the reality that there are real crossover symptoms, there are many symptoms of bipolar that appear in people with more severe autism but for entirely different causes. Some of these include hyperactivity, disturbed sleep, impulsivity, agitation, and irritability.

While it's reasonable to ascribe some of those symptoms to bipolar disorder, it can be very difficult (especially with a non-verbal individual) to sort out bipolar from autistic symptoms.

Bipolar Disorder vs. Autism

Because people with autism and people with bipolar disorder can sometimes behave in similar ways, at times it can be hard 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 in the early developmental period (before the age of 3).
• Symptoms of bipolar disorder may emerge at any time (and are most likely to appear around the age of 25).
• While the criteria for bipolar disorder specifically include mood-related issues such as mania and depression, criteria for autism are unrelated to mood.
• While people with bipolar disorder may switch between extreme moods of mania and depression, people with autism rarely cycle in the same way.
• People with bipolar disorder who do not have autism are unlikely to exhibit autistic symptoms, such as late or disordered speech or severe social communication issues.

Causes

The causes of these disorders include:

• Genetics: Both autism and bipolar disorder have genetic links and can run in families. It is, however, possible for one twin to have autism or bipolar disorder while the other twin does not. Research suggests that some of the same genes may be implicated in both autism and bipolar disorder (along with other mental and developmental disorders).
• Issues during pregnancy: Autism can result from a mother's exposure to specific drugs during pregnancy (valproic acid, for example). Autism is also more likely if a baby is born preterm, or if the parents are older (though it's not clear why these are risk factors). Bipolar disorder does not seem to be caused by these issues.
• Environmental issues: Episodes in bipolar disorder can be set off by a stressful event such as a death or divorce. This is not the case with autism.
• Brain structure 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, signs, and symptoms of autism and bipolar disorder can look similar. For example, people with both disorders can exhibit:

• Irritability 
• Disturbed sleep 
• Repetitive behavior 
• Distractibility and impulsivity  
• Loud, rapid, and virtually nonstop speech   
• Impulsivity that 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 have concerns that your child with autism is bipolar, you should contact your physician—but also bear in mind that:

• Autism is not a cyclical disorder. You should not see sudden and severe mood shifts occurring for no apparent reason.
• Autism can't be "set off" by an event. Symptoms must appear before the age of 3, and, while autistic symptoms can improve, you will not see a point at which it "disappears."
• Autism, on its own, should not cause severe depression or suicidal thoughts (though people with autism can feel depressed, just like everyone else, when circumstances are depressing).
• People with autism are likely to have moderate to extreme difficulties with speech, social communication, awareness of others' needs and feelings, and may have significant sensory challenges. These are not necessarily symptoms of bipolar disorder.
• "Stimming" (rocking, pacing, mumbling, etc.) is common with autism and is a tool for self-calming. If it has been present consistently for a long period of time, it is probably not related to bipolar disorder.
  

Diagnosis

Autism is typically diagnosed in early childhood, though very high functioning individuals may be diagnosed as teens or adults. Autism is generally diagnosed through observations and specific tests and questionnaires, as there is no biological marker for the disorder. Diagnosticians are looking for:

• Specific behavioral differences that are typical of autism (stimming, lack of eye contact, etc.)
• Speech delays or idiosyncrasies such as echolalia (repeating the same phrases or "echoing" TV or movies)
• Sensory dysfunction
• Social and communication delays and disorders

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

Like autism, bipolar disorder has no biological marker, so physical tests can only rule out other issues.

Treatment

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 anti-anxiety medications and second-generation antipsychotics.

Treatment of bipolar disorder is more likely to include specific mood stabilizers such as lithium. Second-generation antipsychotics and antidepressants may also be used. In addition, 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 might have autism or bipolar disorder, your first step should include a visit to the pediatrician. Describe your child's symptoms, and ask that your child be evaluated for these disorders.

Be sure that the person or team doing the evaluation has solid experience with both disorders, as it is easy to mistake one for the other or to miss signs of mental illness in a child with autism.

Adults seeking diagnosis and treatment should document symptoms carefully, with particular attention to these questions:

• How long have these symptoms been present? (If they appeared suddenly they are almost certainly not related 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? (While 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 lights and loud noises, for example), or speech delays? (While some of these symptoms occur in both disorders, if all of them are present they may suggest autism.)

Summary

Bipolar disorder and autism spectrum disorder are not the same. However, they have some symptoms in common, and they 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 methods of treatment are different for the two disorders. Children should be screened for autism and any concerns brought up with the child's pediatrician to get a proper diagnosis. Adults should seek a professional diagnosis.

A Word From Verywell

Both autism and bipolar disorder can appear in the same person, but diagnosis can be tricky. It's especially difficult when the person with autism lacks the verbal skills to describe their emotional ups and downs.

Because of this, it's important to find a highly experienced diagnostician to evaluate the person's symptoms. If you are not comfortable with the diagnosis or have further questions, it's a good idea to ask for a second opinion.

The treatments that work for one disorder may be ineffective or even harmful when inappropriately applied.