What are the Causes of Bipolar Disorders

We may have heard that insanity can be inherited form he family line. Well, basing on medical research, what people may have observed can indeed be true. The research has been made reliable as the study made use of twins. Research of twins give a very good and sufficient proof for the role of heredity in the cause of a mental disorder called a bipolar disorder. Bipolar disorders are characterized by alternating episodes of elation and extreme depression. Within the twins whose genetic composition are exact with each other, when one twin has bipolar disorder, the other twin has the also the same disorder. This is true in more than 70 percent of cases.
On the other hand, investigations on fraternal twins show a lesser result. Unlike identical twins whose genetic composition are exactly the same with each other, fraternal twins have about half their genes in common. Here, the siblings have bipolar disorder in less than 15 percent of cases in which one twin has the disorder. The degree of genetic similarity seems to account for the difference between identical and fraternal twins. Further evidence for a genetic influence comes from studies of adopted children with bipolar disorder.
The findings reveal that biological relatives of the children have a higher incidence of bipolar disorder than do people in the general population. Thus, bipolar disorder seems to run in families for genetic reasons.
Work-related or personal stress can trigger a manic episode, but this usually occurs in people with a genetic vulnerability. Other factors—such as prenatal development, childhood experiences, and social conditions—seem to have relatively little influence in causing bipolar disorder.
A research showed that the children of identical twins in which only one member of each pair of twins had bipolar disorder. The study found that regardless of whether the parent had bipolar disorder or not, all of the children had the same high 10-percent rate of bipolar disorder.
This medical investigation show that the probability for bipolar illness stems out from genetic predisposition, not from exposure to a parent’s bipolar illness or from family problems caused by that mental disorder.