The causes of bipolar disorder have not yet been precisely determined; however, genetics seem to play a large role. 80-90% of people diagnosed with bipolar disorder have a family history of either bipolar or major depression. However, this does NOT necessarily mean that someone with such a family history will inherit the genetic predisposition of the disease, or if they do, it will eventually develop into symptoms. The inheritance of bipolar disorder is not simple - it involves many genes, some of which are still being discovered and researched.

The following statistics on genetic susceptibility to bipolar disorder are adaptedf from a NARSAD research newsletter article.

The mood disorder symptoms appear to be caused by biochemical imbalances of hormones or certain neurotransmitters in the brain (especially dopamine, serotonin, norepinephrine, and acetylcholine). Genetic influences probably contribute to this; someone who inherits a genetic predisposition for mood disorders might have an abnormal gene(s) that produces too much or too little of certain chemicals in response to certain events. This might explain why manic or depressive episodes are sometimes triggered by stressful life events (however, this is not always the case, and so there is obviously more to the story that we don't know). It's difficult to determine whether these biochemical imbalances are a cause of mood disorders, a result of the symptoms, or a little of both.

The best preventative measure against bipolar is being informed and aware. If you have a family history of mood disorders, knowing the signs and symptoms to watch for will increase your likelihood of recieving an early diagnosis and treatment, which makes the disease much more manageable in the long run. Be aware that females with a family history sometimes show their first symptoms after childbirth (triggered by post-partum depression). Frequent use of alcohol and drugs can trigger a manic episode; substance abuse is also a causal factor in some other psychiatric disorders such as schizophrenia.

• Details on the Causes of Bipolar Disorder - From The US Surgeon General's Report (2002)

General Information on the Causes of Bipolar:

• Let's Talk Facts About Bipolar (American Psychiatric Association fact sheet)
• What Causes Bipolar Disorder? (National Electronic Library for Health - Mental Health)
• Genetics and Bipolar Disorder

Recent News Updates on Research into the Causal factors in Bipolar Disorder

• Families With Severe Form Of Bipolar Disorder Help Scientists Narrow The Search For Disease Genes (April 2003)
• Discovery That Common Mood Disorders Are Inherited Together May Reveal Genetic Underpinnings (Jan 2002)
• Gene Variation Raises Risk Of Bipolar Disorder And Schizophrenia (April 2003)
• UCSD Researchers Identify Gene Involved In Bipolar Disorder (June 2003)
• UCSD Biologists Discover That Nerve Activity, Not Just Genetics Controls Kinds Of Neurotransmitters Produced (June 2004)
  
• Genes Play A Bigger Role In Women's Depression Than In Men's, Twin Study Finds (July 1999)