The exact cause of bipolar disorder is not fully understood. However, experts believe that a number of different factors act together and make a person more likely to develop the condition. These are thought to be a complex mix of physical, environmental and social factors.
Chemical imbalance in the brain
Bipolar disorder is widely believed to be the result of chemical imbalances in the brain. The chemicals responsible for controlling the functions of the brain are called neurotransmitters, examples of which include norepinephrine, serotonin and dopamine.
If there is an imbalance in the levels of one or more neurotransmitters, it may cause the symptoms of bipolar disorder. For example, episodes of mania may occur when levels of norepinephrine are too high, and episodes of depression may be the result of norepinephrine levels becoming too low.
Genetics
Bipolar disorder is also thought to be linked to genetics. Bipolar disorder seems to run in families, and the family members of a person with the condition have an increased risk of developing it themselves.
However, no single gene is responsible for bipolar disorder. Instead, it is thought that a number of genetic and environmental factors act as triggers for the condition.
Triggers
A stressful circumstance or situation often triggers the symptoms of bipolar disorder. Examples of stressful triggers include:
These types of life-altering events can cause episodes of depression throughout a person’s life.
Bipolar disorder may also be triggered by physical illness, sleep disturbances and overwhelming problems in everyday life, such as problems with money, work or relationships.
