Causes (bipolar disorder)

Doctors and researchers don't know exactly what causes bipolar disorder. But a variety of biologic, genetic and environmental factors seem to be involved in causing and triggering episodes of this illness.
Evidence indicates that differences in the chemical messengers between nerve cells in the brain (neurotransmitters) occur in people who have bipolar disorder. In many cases, people with a bipolar disorder may have a genetic disposition for the disorder. The abnormality may be in genes that regulate neurotransmitters. However, not everyone with a family member who has bipolar disorder will develop the disease.
Factors that may contribute to or trigger episodes of bipolar disorder include drug abuse and stressful or psychologically traumatic events.