(GETTY IMAGES)Parents usually enjoy seeing their own characteristics reflected in their children, such as a daughters green eyes or a sons shyness. But studies show that bipolar disorder also runs in families, and experts say that most people who are living with the illness can identify at least one relative who has bipolar disorder or depression. What happens when one or both parents are bipolar and their child is diagnosed with a disease thats caused a parent great hardship?

“You'll certainly find higher risk in families where someone has bipolar disorder,” says Greg Simon, MD, a psychiatrist and researcher at Group Health Cooperative in Seattle and the chair of the scientific advisory board of the Depression and Bipolar Support Alliance. “But the risk is still not that high in absolute terms.”

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In other words, the genetic link doesnt mean that one bipolar parent or even two will necessarily produce a bipolar child. Other factors, including stressful life events, abrupt changes in sleep patterns, and chronic medical illnesses, can contribute to a persons risk.

Studies report rates of bipolar disorder between 4% and 15% in children with one bipolar parent, compared to 0% to 2% in the offspring of parents who don't have the disorder. And if both parents are bipolar, rather than just one, a child is about 3.5 times more likely to develop the condition.

Some bipolar parents have regrets
Even so, when a parent who is bipolar sees the disease manifest itself in a child, statistics dont seem to matter anymore. It just feels as if the disease is simply hereditary.

Stacey Galka, 38, of Denver, is a single mom who was diagnosed with bipolar disorder when she was 26. At that point, her daughter was already 5 years old. Stacey says her own diagnosis was a relief because it helped her to make sense of why her life had always been so chaotic, but when her daughter was diagnosed with bipolar disorder at age 13, Stacey had trouble accepting it. “In all honesty, if I had known then what I know now, I would have never had a kid,” she says. “It was difficult enough for me to go through what I did."

While the chances of some children having bipolar disorder are heightened by genetic factors, there are ways of treating the illness. Ronald R. Fieve, MD, a psychopharmacologist in private practice in New York City, notes that medications have revolutionized the lives of people living with bipolar disorder and provided successful treatments.

In order to mitigate the onset of bipolar disorder in any at-risk child, however, Dr. Fieve says that general health is very important: normal sleep patterns, a healthy diet, regular exercise, and the avoidance of drugs and alcohol. Sleep deprivation or major life stresses can precipitate the onset of a manic or depressive episode.

Brandi, 34, lives in Colorado Springs. She was diagnosed after her first pregnancy kicked her into a manic episode, and medications have stabilized her moods. Now, she has two daughters. Although she worries that theyll inherit the disorder, she says she is more concerned about how her own bipolar disorder may affect her. As a bipolar parent, she tends to yell, make bad decisions with food or shopping, and gets easily agitated when her symptoms flare. “I do worry that they're going to end up with something. I keep a close eye on my 3-year-old,” she says. “I have to keep telling myself, ‘This is normal 3-year-old behavior. She's just fine. So I guess it's not a matter of being afraid of her being bipolar so much as I'm afraid of how she's going to turn out because of my bipolar.”

A genetic test for bipolar on the horizon
Experts have discovered that there may be many more genes involved in bipolar disorder than scientists initially thought.

Alexander B. Niculescu III, MD, PhD, an assistant professor of psychiatry and medical neuroscience at the Indiana University School of Medicine, is working to develop a genetic test that, along with other information such as family history, would evaluate a childs risk for developing the illness.

“These tests will be just another piece of information that says you may be at higher (or lower) risk,” he says. "Your genes are not necessarily your destiny. For the illness to manifest itself, you have to have environmental effects—stress, exposure to infections, neurotoxins, drugs. In the end, prevention and early intervention in at-risk individuals can make a big difference.”

Dr. Niculescu and his team are also developing blood biomarker tests to assess illness severity and measure response to treatment. “Once the illness has manifested itself, we need to have objective tools to do a better job of treating people and to help personalize treatment,” he says. “Blood biomarker tests are such tools.” Both the genetic tests and the biomarker tests will likely be available within the next five years.