What causes manic depression? The medical community is at a loss as to explain the exact causes of manic depression. But as they look at the incidence of manic depression, medical experts seem to think that genetics might just play a role.

They believe this because between 80 to 90 percent of those who are diagnosed with manic depression have a family history of this mental health illness whose hallmark symptoms include mood disturbances which fluctuate from severe forms of depression to euphoric bouts of mania.

But having said this, it does not necessarily mean that if you have a family history of manic depression that you are automatically going to develop this mental health issue. It doesn't even mean that you've inherited the disposition towards manic depression.

The genetic implications of manic depression are more complicated than that. One of the reasons is that manic depression involves a wide variety and number of genes. Those who study genetics, have in fact, developed a very rough chart of the rate of incidence.

Out of the general population only about one percent will develop manic depression. However, when an individual has a 'second degree relative' who has manic depression, that is an uncle or an aunt, his chances of acquiring the illness jumps to about three to seven percent.

As manic depression touches closer to the immediate family, your chances of developing this disorder increase. If you have a sibling - a brother or sister - with manic depression, then your risk of developing it yourself climbs to 15 to 25 percent. This rate stays the same even if your sibling is a fraternal twin.

If one of your parents had been diagnosed with manic depression, then your odds of developing this mental health disease increase to 15 to 30 percent. And if both of your parents suffer with manic depression, your odds increase even more. Your chances are between 50 and 75 percent of acquiring manic depression yourself.

Finally, if you have an identical twin who suffers from manic depression, then your stand a 70 percent chance of developing manic depression yourself.

Manic depression symptoms seem to be caused by biochemical imbalances of hormones or specific neurotransmitters in the brain. Those most affected include dopamine, serotonin, nor epinephrine and acetylcholine.

While genetic influences contribute to this situation inherent in manic depression, an individual with a genetic predisposition for the mood disorder may also have abnormal genes that produce an abundance or scarcity of chemicals in response to certain events.