Familial Links & Bipolar Disorder
by Ray Dallas
Bipolar disorder tends to run in families, according to the National Institute of Mental Health (NIMH), although much about the genetics is still a mystery. Bipolar disorder affects approximately 5.7 million American adults.
According to the NIMH, children of parents with bipolar disorder are four to six times more likely to develop it than children of parents who do not have it.
According to the Mayo Clinic there is evidence of genetic links between schizophrenia and bipolar disorder. So, relatives of people afflicted with schizophrenia may be at higher risk for bipolar disorder.
Heredity and Symptoms
There is also evidence that genetics play a role in how the disorder manifests. For instance, the age of onset of symptoms appears to run in families, as does the frequency of manic episodes.
Not a Guarantee
According to a study by the National Alliance for Research on Schizophrenia and Depression (NARSAD), most people with a family history of bipolar disorder do not get it, though it depends on the proximity of your genetic relationship.
Here are the probabilities of developing bipolar based on the family members that have bipolar disorder:
2nd degree relative (i.e. aunt/uncle) - 3 to 7 percent
Sibling - 15 to 25 percent
Fraternal Twin - 15 to 25 percent
One Parent - 15 to 30 percent
Both Parents - 50 to 75 percent
Identical Twin - 70 percent
According to Mayo clinic, there seem to be contributing factors other than heredity. There have been cases in which one identical twin had bipolar disorder while the other did not. Because twins have identical DNA, this indicates that other factors, such as a stressful environment or loss of self-esteem may contribute.