A study published in this month’s General Archives of Psychiatry entitled “Advancing Paternal Age and Bipolar Disorder,” reports that children of older fathers have a higher risk of developing bipolar disorder than children of younger fathers. This is a large study, and the data are quite strong. Fathers age 40 and older show some increased risk of having a child with bipolar disorder, but the risk really grows with fathers ages 55 and older.

Recently, the NIMH (National Institute of Mental Health) distributed a press release entitled “Largest Study of Its Kind Implicates Gene Abnormalities in Bipolar Disorder.” According to the press release, this “largest genetic analysis of its kind to date for bipolar disorder has implicated machinery involved in the balance of sodium and calcium in brain cells.” As the press release points out, no single gene has been identified as the “bipolar gene.” Researchers generally agree that multiple genes contribute to make an individual more susceptible to the eventual onset of bipolar disorder.

For more about bipolar disorder genetics and heredity, check out Dr. Fink’s two-part series – “Bipolar Disorder & Heredity: The Genetic Link.”

In Part I of this two-part series, we examined the role that genetics likely plays in the onset of bipolar disorder and learned that genetics contributes up to 80%, with environmental factors contributing about 20% or more. (This means that if someone has bipolar disorder, the cause of it is 75-80% due to genetics. It does not mean an individual in a family with a history of bipolar has a 75-80% chance of developing it. See Part I for statistics on the inheritability of bipolar.)

It appears that for most people there needs to be some environmental factors that “turn on” the genes responsible for one’s vulnerability to bipolar disorder. Many of these environmental triggers may occur early in life and may include things such as:

Although doctors and research scientists seem obsessed with mapping the human genome and identifying possible genetic links to every affliction from Alzheimer’s to zits, it’s parents and children who tend to be most concerned about bipolar disorder and heredity. Parents often ask me how likely it is that their children will develop bipolar disorder if someone in the family has it. And one of the biggest sources of anxiety for children of parents with bipolar is whether they will eventually “get it.”