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.
More top news
We look back at some of the stories, people and events that stood out in 2014.
It will be a frosty Christmas morning across the UK but any chance of snow is limited to the Scottish mountains.
Fainting dogs, dancing grooms and an attacker who picked on the wrong girl all featured highly in our most-read stories of the year.