There is no single cause for bipolar disorder; however, the two traditionally agreed-upon causes are a hereditary component and a biological (chemical) component.


There has been strong evidence to show that bipolar disorder does run in families, showing the hereditary component, but this does not necessarily mean that every child of a parent with bipolar disorder will develop the disorder.  There is a greater risk for it, but it does not happen in every case.


On the other hand, over half the people with bipolar disorder have a family member with a mood disorder, such as depression or bipolar disorder, according to research I have done for my website devoted to bipolar disorder. .


Some brain imaging studies have shown physical changes in the brains between those who have bipolar disorder and those who do not; however, there is not enough evidence to show that we can predict who is going to get bipolar disorder at birth.


We do know that people who have bipolar disorder have a chemical imbalance in their brains, though, because we can restore that imbalance to normalcy (and regulate moods) through the use of medication.


Although substance abuse is not a cause for bipolar disorder, it can worsen the disorder by interfering with recovery.


There are also environmental and psychological factors to bipolar disorder that, although they do not cause bipolar disorder by themselves, do cause the symptoms of the disorder to manifest in a bipolar episode.


These factors are called "triggers," and can include the following:


·         Stress

·         Lack of sleep

·         Use of alcohol or drugs

·         Seasonal changes

·         Prescription medications