Causes and Risk Factors
What are the Causes of Bipolar Disorder?
The exact causes of bipolar disorder are not fully understood. Scientists believe that several factors seem to be involved in causing and triggering bipolar episodes. Some of the causes of bipolar disorder are listed below
Brain Structure and Functioning
Modern brain-imaging studies reveal that the brain of people with bipolar disorders may function differently than that of normal people. Recently, a study revealed that onset of bipolar disorder is associated with reduction in intracranial, whole brain, total grey and white matter. This suggests presence of brain abnormalities in people with bipolar disorder. Some magnetic resonance imaging (MRI) studies suggest that brains of people with bipolar disorder show reductions of whole-brain and prefrontal lobe volumes, and enlargement of brain structures such as lateral ventricles and globus pallidus.
Imbalance in Neurotransmitters
Imbalance in the production or levels of neurotransmitters especially dopamine, serotonin, norepinephrine, and acetylcholine play an important role in development of bipolar disorders. Studies indicate that levels of norepinephrine and serotonin are low in bipolar disorder. However, this is just an assumed mechanism as most of the data has been derived from post-mortem brain.
People who have a blood relative with bipolar disorder are commonly affected. Scientists suspect involvement of genes. People with either one parent or both the parents with bipolar disorder are at 15 to 30 percent and 50 to 75 percent risk of developing the disorder, respectively.
Environmental and Social Factors
Stress, abuse, trauma or losing a loved one may cause bipolar disorder in some people.