What causes bipolar disorder (manic depression)?

Bipolar disorder is strongly predetermined by genetics. Of children with two parents who have mood disorders, almost all will develop a mood disorder themselves; of children with one parent with mood disorders, about a quarter will eventually develop the disorder. In rare instances, diseases such as AIDS, infections of the brain, and epilepsy can bring on manic episodes. An imbalance of thyroid hormones can be a contributing factor, but this is rare. If a teen is bipolar, medications for ADHD and depression will worsen their condition, causing manias which might not have previously been present.

Environmental Factors

There is evidence that BPD may be triggered by environmental stresses. Stressful life events such as the death of a loved one, the loss of a job, or the birth of a new baby have the potential to bring about the onset on Bipolar Disorder. There is evidence that those with Bipolar Disorder may have difficulty coping with outside stressors. Once the disorder is triggered, it seems to manifest in unpredictable ways. After a stressful event, a psychological and physiological cycle of mania and depression develops in those with Bipolar Disorder.

Genetic Disposition

Bipolar Disorder typically runs in families. This has led researchers to examine the genetic composition of those with Bipolar Disorder to determine which genes may cause bipolar depression and mania. Studies have concluded that although genetics play a role in the likelihood of developing symptoms of Bipolar Disorder, there is no exclusive link to genetics. Studies of identical twins, who share identical genes, reveal that if one twin has Bipolar Disorder, that does not necessarily mean the other twin has it. If Bipolar Disorder were exclusively genetic, both twins would always have the disorder. Research has shown, however, that Bipolar Disorder tends to run in families, and those with family members diagnosed with the disorder are more likely to develop the disorder.

Additional studies indicate that Bipolar Disorder does not occur from a solitary gene. It appears that many different genes act together in conjunction with a person’s environment to create symptoms of Bipolar Disorder.