biological causes of bipolar disorder
Neurochemical Factors in Bipolar Disorder. Bipolar disorder is primarily a biological disorder that occurs in a specific area of the brain and is due to the dysfunction of certain neurotransmitters, or chemical messengers, in the brain.
The exact cause of bipolar disorder is unknown, but several factors may be involved, such as: 1  Biological differences. 2  People with bipolar disorder appear to have physical changes in their brains.