With any mental health disorder, there is always a great deal of debate as to whether the illness is caused by nature or nurture. Or in other words, will you develop bipolar as a result of a dysfunctional childhood, or are you predetermined to develop bipolar because your mother, father, or both have been diagnosed with the disorder? So is bipolar hereditary, or are you no more likely to develop the symptoms of bipolar disorder than your next door neighbor?
Is bipolar hereditary?
In an attempt to determine whether bipolar disorder is hereditary, lots of research has been carried out via twin studies and examining multiple families and adoption records, all of which has concluded that there are definite bipolar hereditary factors at play in the incidence of bipolar cases.
Bipolar hereditary statistics have proven that when bipolar disorder has been diagnosed in a family member, close relatives, for example parents, siblings, and children are significantly more likely to be subsequently diagnosed with bipolar disorder.
Having a relative diagnosed with bipolar disorder automatically increases your risk of developing the illness at some point. The risk associated with a secondary relationship, such as an aunt or a cousin, is relatively low, but if a grand parent has bipolar, the risk is higher, and if a parent has the illness, the odds on you being diagnosed with bipolar are much greater.
What is the bipolar hereditary percentage in families?
When one parent has been diagnosed with bipolar disorder, you are 25% more likely to have the illness, but if both parents are bipolar, the risk factor rises to 50%. There is also evidence to indicate that for each generation of the same family with bipolar disorder, the risk associated with the illness rises a further 5%
What is the bipolar hereditary percentage in twins?
Similar findings have also arisen from twin studies into bipolar hereditary factors. In the case of identical twins who share identical genetic material, when one twin has been diagnosed with bipolar disorder, there is an 80% chance that the other twin will go on to develop the symptoms of bipolar. The bipolar hereditary percentage is lower for fraternal twins as they originate from two separate eggs as opposed to the same egg, but they still have a 16% chance of developing bipolar if the other twin already has the illness.
Twin studies certainly support the theory that there is a strong genetic link with cases of bipolar, as even when identical twins have been separated at birth and raised in completely different ways, if one is diagnosed with bipolar disorder, the odds of the other twin developing the illness still remain the same.
However, despite the fact that there are clearly genetic factors at play in the occurrence of bipolar disorder, the illness is a highly complex one and a hereditary predisposition is only one piece of a very large and complex puzzle. So if you are at all concerned about the possibility that you or a close relative is at risk of developing bipolar, ask your doctor for advice.