Pathophysiology of Bipolar Disorder


The pathophysiology of bipolar disorder refers to the changes of normal physiological and biochemical functions associated with the illness. Understanding the pathophysiology of bipolar disorder is an ultimate goal of many researchers and clinicians, but to date it remains poorly understood. We still don’t know all the physical factors involved in the development of bipolar disorder, but fortunately researchers are continuing to learn new information all the time.

Biological Differences

Imaging studies have shown that people with bipolar disorder appear to have structural changes in their brains that may be related to the causes of their disorder. Brain areas such as the amygdala, basal ganglia, and prefrontal cortex have all been shown to have physical differences in people with bipolar disorder when compared to those without a mental illness. In addition, people with bipolar disorder also show abnormal myelination in some areas of the brain..This suggests that damage to the areas of the brain that regulate emotion may be a cause of bipolar disorder.

Neurotransmitters and Hormones

Bipolar disorder and other mood disorders seem to be associated with an imbalance in brain chemicals known as neurotransmitters, specifically serotonin, norepinephrine, and dopamine. An imbalance in hormone levels may also be present in people with bipolar disorder.


There is clearly a hereditary component to bipolar disorder, as people with a close blood relative with bipolar disorder are significantly more likely to develop the disorder themselves. The genetic causes of bipolar disorder are complex, with more than one gene involved in development of the disorder. Past research studies have pointed to a handful of genes that seem to play a role in bipolar disorder, and additional studies are ongoing.

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