Bipolar disorder---known also as manic depression---is a disorder of the brain that causes unusual shifts in mood and activity and energy levels, which all affect a person's ability to carry out everyday activities, as the National Institute of Mental Health explains. Often developing in a person's late-teen or early-adult years, this disorder can have a profound negative impact on personal and professional relationships. No single cause is responsible but rather a culmination of several different risk factors.
Genes
The NIMH points out that bipolar disorder tends to run in families, and because genes are the building blocks of heredity, bipolar disorder may pass from parents to children. According to NIMH, a person with a parent or sibling who has this disease is four to six times more likely to experience it themselves in comparison to people with no hereditary link.
Neurotransmitters
Bipolar disorder is a biological disorder, meaning it tends to occur in one specific are of the brain and is the result of neurotransmitter dysfunction. Neurotransmitters are chemical messengers responsible for relaying messages to and from the cells in the brain. The most common are norepinephrine, serotonin and dopamine. When one or more of these messengers are out of balance, bipolar may result.
Different Brain Structuring
Both the Mayo Clinic and the NIMH explain that those with bipolar disorder may have different brain structures, or physical changes in their brain, which differ from the brains of healthy people, or the brains of people with other mental disorders. Recognizing these differences may one day lead to an ability to prevent bipolar disorder, according to NIMH.
Medications or Medical Condtions
Some medications, such as corticosteroids or cancer medications, may cause symptoms that resemble mania, as can appetite suppressants, cocaine and ecstasy. Certain medical conditions such as Parkinson's syndrome and dementia may also spark features of bipolar, according to Aurora Health Care.
