Bipolar disorder (formerly known as manic depression) is a mental health condition characterized by extreme mood changes that do not necessarily depend on environmental circumstances.
People with bipolar disorder experience shifts between extremely elevated mood (mania) and low mood (depression). In some cases, several years may pass between episodes. Some people do not experience symptoms between episodes. It is estimated that 1% of the population lives with bipolar disorder.
What is mania?
Manic episodes are characterized by elated feelings, excessive energy and activity, and an increased sense of self-esteem and grandiosity. Many define this condition as the complete opposite of depression.
People in a manic episode will experience an upbeat mood and a sense of euphoria. They tend to build ambitious new plans, have rapid taking (also called pressured speech), and racing thoughts that may be difficult to follow.
During a manic episode, people may experience poor decision-making and a loss of patience. In addition, they experience a decreased need for sleep and an unusually high sex drive.
Manic episodes are gradual and can last from a week to several months.
What is depression?
Depressive episodes are characterized by a decreased, sad mood accompanies by feelings of helplessness, despair, and hopelessness.
People in a depressive episode tend to distance themselves from their environment (social withdrawal). In some cases, they may even feel unable to get out of bed and can spend most of the day sleeping. In addition, they may neglect their personal hygiene. They can also experience thoughts about suicide.
People with bipolar disorder may also experience mixed episodes which include symptoms of both mania and depression, at the same time.
The genetics of bipolar disorder
Although experts still do not hold an exact explanation of the etiology of bipolar disorder, the prevailing explanation is that there are most likely certain genetic components that many people with bipolar disorder have in common. This view is reinforced by finding from research conducted in this field.
For instance, if one identical (monozygotic) twin has bipolar disorder, the other twin’s chances of having this condition are between 40-80%. In fraternal (dizygotic) twins this chance drops to 10-20%. In general, the chances of a sibling of a person with bipolar disorder to also have this condition are 10%.
In addition, it appears that 50% of people with people with bipolar disorder have a family history of this disorder. In certain cases, this condition runs in families for many generations.
It appears that bipolar disorder is not caused by a single gene mutation, and that like many other disorders, is caused by a combination of several mutations.
Is there genetic testing for bipolar disorder?
Although molecular biology has developed significantly in the last decades, and although several areas of chromosomes 18 and 24 are suspected as being common in many people with this disorder, the specific genes responsible for bipolar disorder have not been identified yet.
Therefore, there are currently no prenatal tests available for people interested in having a child, which can detect carriers of the relevant gene mutations. Similarly, there are no prenatal tests that can be performed on a fetus to diagnose bipolar disorder during pregnancy.
