What causes bipolar disorder?

Bipolar Disorder: An Information Guide

Several factors are involved in causing bipolar disorder, and the precise mechanism is not known. However, there is strong evidence that biological, including genetic, factors play an important role. This does not mean that a person has to inherit the genes: the genes involved may be altered when a person is conceived.

Genes are the blueprint for all cells and their contents. Scientists thus believe that changes to genes can lead to faulty proteins being produced within brain cells. These faulty proteins may then result in bipolar disorder. Researchers today are looking at various proteins that may be affected in bipolar disorder. These include:

• proteins such as those involved in making chemicals in the brain called neurotransmitters
• proteins that use neurotransmitters to make the cell do something
• genes themselves.

We do know that too much stress or difficult family relationships do not cause the illness. However, these factors may “trigger” an episode in someone who already has the illness. Nor is bipolar illness a simple imbalance of neurotransmitters, such as serotonin or dopamine. Yet neurotransmitters may be affected during a flare-up of the illness.

What Is a “Trigger” for a Bipolar Episode?

Not all episodes can be related to any particular trigger, but many can. Triggers are situations that can provoke either mania or depression in someone who has already had an episode of illness. Feeling very stressed or continually losing sleep is an example of this kind of trigger. Other triggers are chemical, and include antidepressants that work “too well” and result in mania; common medications, such as steroids (for instance, prednisone used for treating asthma, arthritis, etc.); and street drugs, such as cocaine and amphetamines.

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