Bipolar disorder, known in the past as manic depression, is a condition that affects people's moods, which can swing from one extreme to another.
People with bipolar disorder have periods of:
- Depression - where they feel very low and lethargic
- Mania - where they feel very high and overactive
- Les severe mania is known as hypomania
The exact causes of bipolar disorder are unknown and it is relatively common - around one person in 100 is diagnosed with the condition.