Depression, bipolar disorder, and other types of mood disorders do tend to run in families, and most people with depression or bipolar disorder have at least one relative who also has it. But just because a mood disorder runs in the family doesn't mean that your children are destined to be affected by it. The risk is elevated, but it's not a certainty.
If a parent has depression that began when he/she was an adult, his/her children are two to three times as likely to develop depression as if the parent never had depression. If the parent's depression began before the age of 20, the risk to his/her children is four to five times greater. Children of one bipolar parent are four to six times more likely to develop bipolar disorder than children who don't have a family history of bipolar disorder.
Studies have shown that fathers and mothers are equally likely to pass on mood disorders to their children. But experts also suggest that creating a stable home environment can help reduce the risk. Specifically, making sure your child gets plenty of sleep, eats a healthy diet, exercises regularly, and avoids drugs or alcohol can help prevent the onset of a manic or depressive episode.
If you suspect that your child is showing signs of a mood disorder, it's important to see a doctor immediately for evaluation and treatment.