In the run-up to her 17th birthday in November five years ago, Beth fell asleep — and didn't wake up properly for six months. For 22 hours a day, she kept sleeping, only waking in a dream-like trance to take a little food and drink and go to the toilet.
Over the past five years, Beth's mother, Janine, calculates that her daughter has been asleep 75 per cent of the time.
Beth, now 22, is one of more than 100 young people in Britain diagnosed with Kleine-Levin syndrome (KLS) — known as Sleeping Beauty syndrome.
But that fairy-tale name is far from the grim reality faced by those youngsters who are sleeping through the most formative times of their lives.
Tonight, the condition will be highlighted as part of a TV series on medical mysteries — for KLS is certainly that. Little is known about what triggers the sleep disorder and even less about how to cure it.
What is known is that it mainly hits teenagers — the average age it strikes is 16 — and lasts around 13 years, destroying young people's hopes of passing exams, going to university or forging a career.
At the moment, Beth is two-and-a half months into another deep sleep episode. Nothing — not drugs, loud noises, pleading or cajoling — will wake her.
Researchers believe an infection may set off inflammation in the brain in people with a genetic predisposition, and this may damage the thalamus and hypothalamus, the areas responsible for sleep and sensory input.
Since her diagnosis, Beth has been asleep more than she has been awake, sleeping through many of her birthdays and Christmases, as well as holidays. When she wakes up, she has no recollection she was ill or realisation that time has moved on.
Beth's hopes of getting the four A-levels she needed to train to be a child psychologist faded as she was forced to drop out of college.
And Janine, a single mother, had to give up her job to look after her daughter round the clock.
