Genetics of Bipolar Disorder

As of this writing, the exact causes of bipolar disorder (also referred to as manic-depression) are not known. However, the specific gene or genes that trigger the condition are currently being researched and identified, although this is a difficult task since there are a large number of them. Nevertheless, researchers and psychiatrists are in agreement that genetics play a significant role in that individuals with a family history of bipolar disorder are much more likely than the general population to inherit the disease and exhibit symptoms. For example, an individual is more likely to inherit the disorder (70% - 75% likelihood) if both parents are bipolar, and less likely (15%-30% likelihood) if one parent is bipolar. On the other hand, it is not guaranteed that someone with a family history of the disease will inherit it, and if they have, it is also not guaranteed they will exhibit any of its symptoms.

Genes implicated so far include DAOA (G72) and BDNF (Journal of Medical Genetics 2005; 42:193-204). Two years after the publication of this paper the authors (who are based at Cardiff University in Wales) further identified many genes that they believe increase an individual's risk of having bipolar disorder. Each gene apparently makes its own small contribution to the illness. It is hoped that such discoveries will lead to better diagnosis and new treatments such as drugs, education, and lifestyle advice.

Physicians and researchers believe the symptoms of bipolar disease are caused by an imbalance of the following neurotransmitters in the brain: acetylcholine, dopamine, norepinephrine, and serotonin. Bipolar disease is characterized by an alternation in mood between extreme highs (manic phase) and extreme lows (depression phase). A bipolar individual in a manic phase might exhibit the following behaviors: agression, sleeplessness, rapid speech and rapid thoughts, increased risk-taking, compulsive shopping, night terrors, lack of concentration, increased sex drive, euphoria, and an inflated sense of self. A bipolar individual in a depressive phase might exhibit some or most of these behaviors: suicidal ideation, hopelessness, irritability, fatigue, loss of interest in daily activities, disruption of sleep patterns, and anxiety, guilt, and/or sadness.

Bipolar disorder is a condition that requires treatment over the course of the afflicted individual's lifetime. The core treatments for bipolar disorder include medication, psychotherapy, electroconvulsive therapy, and, in extreme cases, hospitalization. The types of medications available for individuals with bipolar disorder include antidepressants, mood stabilizers, and anti-seizure medications. There are also different types of psychotherapy available: behavior modification and cognitive behavioral therapy, family therapy, and group therapy.