The exact causes of bipolar disorder aren't known, but it’s thought the following play a part in the condition:
* Genes seem to be important; if you have a relative with bipolar disorder, then your chance of developing the condition is higher.
* There may be a physical problem with the brain systems which control mood - so bipolar disorder can often be controlled with medication.
* Stress can trigger mood swings.
There are a number of types of bipolar disorder:
* Bipolar I. There has been at least one high, or manic episode, which lasts for longer than one week. You may have only manic episodes, although most people will also have periods of depression.
* Bipolar II. Where you have more than one episode of severe depression, but only mild manic episodes (called ‘hypomania’).
* Rapid cycling. You have had more than four mood swings happen over a 12 month period. This affects around one in ten people with the condition.
* Cyclothymia . The mood swings are not as bad, but are often longer.