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What Causes Bipolar Disorder, and How Is It Treated?

  • Published6 Jul 2018
  • Reviewed6 Jul 2018
  • Author Levi Gadye
  • Source BrainFacts/SfN

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Bipolar disorder is a severe mental illness that affects nearly three out of every 100 adults every year. It can interfere with a person’s ability to hold a job or maintain relationships with friends and family. It can even lead to suicide. And while millions of people worldwide live with bipolar disorder, it can take years to be properly diagnosed, depriving them of the help that they need.

So, what, exactly, is bipolar disorder? Its name reflects two extremes, or poles, that people with bipolar disorder experience with their mood: depression and mania. 

The depressive pole of bipolar disorder can look just like depression. People with depression may experience low appetite, low self-esteem, or suicidal thoughts. 

The manic pole of bipolar disorder is the polar opposite of depression. A manic person can have an elevated mood or feelings of grandiosity. They might be relentlessly talkative, unable to sleep, hyperactive, or exhibit weird or risky behavior. They may claim to have special powers or express paranoia, anger, or anguish.

A person with bipolar disorder may swing between depression and mania rarely or frequently. For most patients, though, one or two severe swings between the poles occur each year. 

The brain is the source of our emotions, but we don’t fully understand how it produces the extremes seen in bipolar disorder. However, we’ve known for nearly a century that bipolar disorder is heritable, or passed down in families. This means that genes play a significant role in its development over a person’s lifetime. 

Because bipolar disorder is heritable, scientists are interested in which genes are responsible for the condition. But it turns out that identifying these genes is not a simple task. For one, we know that many genes influence the risk of bipolar disorder, rather than just a few genes. And even in identical twins, who have the exact same genetic code, bipolar disorder can affect just one twin. This suggests that environmental factors, like childhood trauma, grief, or even recreational drug use, may also contribute to bipolar disorder.

Bipolar disorder is treated with an emphasis on alleviating depression and mania in the short-term, with the goal of stabilizing a person’s mood in the long-term.

The depressive pole of bipolar disorder can be treated like depression itself, using antidepressant drugs. Because antidepressants lift up a person’s mood, though, they also risk pushing a person with bipolar disorder into a state of mania. So psychiatrists must stay on the lookout for signs of mania in bipolar patients who are being treated for depression.

Similarly, the manic pole of bipolar disorder is treated with drugs that alleviate mania. Such antipsychotic drugs dampen symptoms of mania, like paranoia or dangerous behavior. However, antipsychotics may drag a patient with bipolar disorder back down into depression, so typically they are not a permanent solution.

In the long-term, treatment of bipolar disorder is based on drugs which are known as mood stabilizers. The most famous of these is lithium, which is the most effective long-term treatment for bipolar disorder. About 30 percent of bipolar disorder patients will overcome their symptoms while taking lithium. If patients take their lithium diligently, the drug can allow them to lead more stable lives. Other mood stabilizers, like valproate or gabapentin, are sometimes used instead. The most severe cases of bipolar disorder may be treated with drug combinations, like lithium with valproate, lithium with an antidepressant, or lithium with an antipsychotic. Some antipsychotics are also used for long-term mood stabilization and can be given in conjunction with lithium in acute manic phases.

Ultimately, treating bipolar disorder is an art. Psychiatrists must balance the use of drugs that lift mood up or down, mood stabilizers, psychotherapy, and psychoeducation: The latter helps patients identify their own symptoms and seek treatment. Psychiatry rarely succeeds using just one approach, and treatment of bipolar disorder is no exception: it has many layers. 

Despite our lack of understanding of the causes of bipolar disorder, scientists today combine forces to tackle its mysteries in the hopes of helping patients. Using genetic data from thousands of patients around the world, teams of scientists are trying to identify the many genes that may, in sum, play a big role in bipolar disorder. Someday, it may be possible to use this data to help identify patients with bipolar disorder and match them with the most effective therapies. 

This Ask an Expert was answered by Thomas G. Schulze as told to Levi Gadye for

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