The genetics of Bipolar Disorder are the most intensively studied of all psychiatric diseases. Although no single cause may ever be found for Bipolar Disorder, a combination of biologic and genetic factors, along with chemical imbalances in the brain, are usually discussed as factors affecting the cause of the disorder.

Multiple genes, involving several chromosomes, have been linked to the development of Bipolar Disorder. Although, the definite cause for bipolar disorder is not in agreement by many experts, experts do agree that genetics most likely do play a large part in causing Bipolar Disorder.

Genetics and heredity are words often interchangeable in articles and reports you might find on the Internet; in addition, you might also find terms such as genetic influence, genetic loading, genetic factors, genetic overlap, susceptibility and predisposition. All these complicated terms center around is the assumed fact that Bipolar Disorder may be hereditary—in other words, Bipolar Disorder seems to run in families.

One study done on twins reported that if one twin developed Bipolar Disorder, the likelihood of the other twin developing bipolar is 85-89%. The study stated that this high probability comes from the genes they share; as I said, from their genetic predisposition, or heredity.

Genetics and Bipolar Disorder came into prominence in the June 16, 2003 issue of the journal Molecular Psychiatry, when researchers at the University of California, San Diego (UCSD) School of Medicine reported findings in which they identified a specific gene which reportedly causes Bipolar Disorder.

The research team in this study hypothesizes that a mutation in this specific gene causes the bipolar individual to become hypersensitive to dopamine, leading to the mood extremes that characterize Bipolar Disorder.

Before the UCSD School of Medicine Study, Bipolar Disorder was, genetically speaking, generally thought to be caused by a problem with multiple genes. The focus of the UCSD study was the discovery of genetic defects that cause Bipolar Disorder.

The UCSD study was the first study to pinpoint a precise gene involved with Bipolar Disorder.

Further genetic research since the UCSD study has uncovered six genetic mutations involved with Bipolar Disorder, and research in recent years has pointed to several chromosomes (thread-like strands that carry genetic information) as sites for the multiple genes that cause Bipolar Disorder.

Source: University of California, San Diego (UCSD) School of Medicine Press Release