Bipolar depression can cause dramatic changes in behavior, mood and thinking. Often referred to as bipolar disorder or manic depression, it causes people to experience periods of severe depression followed by delirious highs of mania. Unlike ordinary mood swings, the symptoms of bipolar disorder can interfere with a person's ability to function on a daily basis. While medical evidence does not point to one specific cause that leads to this disease, there do appear to be a variety of conditions and stressors that can trigger its onset.
Genetics
A large body of research indicates that bipolar disease can be an inherited disorder and that people who have a family history of depression are at higher risk than than those who don't. According to AllAboutDepression.com, approximately 50 percent of those diagnosed with bipolar disorder have a parent with a history of clinical depression. The argument for genetics is furthered by National Institute of Mental Health (NIMH) statistics stating that children with a parent or sibling with bipolar depression are four to six times more likely to develop the illness.
Environmental Triggers
There are several environmental factors that perhaps in combination with genetic predisposition can trigger a bipolar depression or manic episode. According to Helpguide.org, stress caused by major life events, whether good or bad, can trigger bipolar disorder in someone with a genetic vulnerability. Examples of a stress-triggering event can include leaving home, marriage and losing a loved one or a job. Helpguide.org also explains that the loss of sleep, even as little as missing a few hours, can trigger an episode of mania.
Brain Development Patterns
Brain-imaging studies are helping scientists learn what happens in the brain of a person with bipolar disorder, according to NIMH. Brain-imaging tools allow scientists to study the brains of those with and without mental disorders. The NIMH website points to a study in which an MRI identified a pattern of brain development in children with bipolar disorder to be similar to that of children with a similar condition known as "multi-dimensional impairment." This discovery suggests a specific brain development pattern may be linked to the development of bipolar depression.
