"Rachel is fifteen-year-old girl who has suffered episodes of depression in the past. Two months ago she started to talk very quickly and seemed to have lots of energy. She was excited about everything and was making all her friends laugh a lot.

Over a three-day period Rachel barely slept or ate and started to say things that did not really make sense; for example, she told friends that was a princess in Taiwan. She also started swearing and became extremely flirtatious, which was out of character. She is quoted as saying, "I've never felt so great - I'm flying. I'm eleven on a scale of one to ten."

Rachel's parents were very worried and on the fourth night of her not sleeping, they took her to the local A&E department, where she was seen by a psychiatrist who arranged for her to stay in hospital. A diagnosis of bipolar disorder was confirmed and treatment was given to bring Rachel's mood back to normal. She now has treatment to help prevent episodes of both depressed and abnormally high mood in the future.

She has been working with a community psychiatric nurse to improve her abillity to recognise her own mood state and take measures to protect herself from further episodes."

Extract from The Young Mind: an essential guide to mental health for young adults, parents and young adults