Bipolar disorder is a complex psychiatric disorder that is thought to be caused by a combination of genetic and environmental factors. Genetics plays a significant role in the development of bipolar disorder, with many studies indicating a strong familial link. People who have a close family member (such as a parent or sibling) with bipolar disorder are at increased risk of developing the condition themselves. However, genetics alone do not determine whether a person will develop bipolar disorder. Environmental factors also play a role in the onset and expression of the disorder. These may include stress, trauma, substance abuse, and certain medical conditions.

In summary, bipolar disorder is not exclusively inherited, but a genetic predisposition combined with environmental factors can contribute to its development.