Cheryl Wray, 22, from Essex, thought she had strained a muscle while working in a supermarket but Stephen Kittles (left with Ms Wray), 27, insisted she see her GP. She was diagnosed with a satsuma-sized precancerous tumour on her pancreas and had to have surgery to remove the tumour and her spleen (she is pictured, right, in hospital with her father Patrick).

OCD, a complex condition characterised by irrational thoughts and repetitive behaviours, is affecting an increasing number of families - like the Pearces, left, and the Hughes family, right. Imogen Pearce, 18, left, became convinced, apropos of nothing, that if she ate anything other than icing sugar, her mum Deborah, far left, and the rest of her family would die. Billy, 17, far right, was obsessed with hygiene, to the extent that he swilled his mouth with household disinfectant. Mother Laura, right, described the experience as a 'nightmare'.

In his 20s, Barry Austin from Solihull was on a mission to become Britain’s fattest man and famously consumed up to 29,000 calories a day in his bid to claim the dubious record. Now, aged 46, his goal is simply to survive another year. Almost 65st at his largest, he is now 20st lighter, but battles obesity related illnesses, and has been housebound for three years.

The broadcaster, pictured with partner Alice Arnold, who fronted last year’s Olympics coverage, was diagnosed with thyroid cancer in 2009. Ms Balding underwent surgery to remove her thyroid gland, followed by radiotherapy. But although she worries that the disease may return, she has vowed to ‘deal with it differently next time’. She is now fronting a Tree of Light campaign run by Macmillan Cancer Support in memory of those affected by the disease.

Delfina Cedeno, from the Dominican Republic, has an anxiety disorder which causes her blood vessels to rupture and the blood to seep out of her eyes and skin. Her condition originally left her suicidal and she took an overdose. But her life dramatically changed after she got a visit in hospital from a young man called Recaris Avila, who had heard of her story. Miss Cedeno said: 'He said I was beautiful. I will remember that moment for the rest of my life.' The couple are now engaged and she is taking medication to control her condition.

William Balestrini, three, from Crawley, has autosomal recessive polycystic kidney disease which causes cysts to develop in the kidneys, damaging the tissue. The condition made him sensitive to chocolate and he was not able to eat it until he was given a new kidney by his father, James. He is pictured (right) in hospital after the transplant.

With her clear skin, supermodel-long legs and slim figure, Faye Campbell looks like she knows how to look after herself. Such a physique, one assumes, must be down to a disciplined regime of exercise coupled with a restricted and controlled diet. And, yes, certainly, one of those points is true: Faye's diet is indeed restrictive, but not in the way you'd expect.

Elizabeth Cathey, 26, from Worcester, was told her implants would be removed, but could not be replaced (pictured right, before surgery). Seeing her distress, friends and family rallied round to raise funds for the replacement surgery. As she PIP scandal broke in 2011, she realised with horror that she too might be affected. She said: 'The idea that I could have toxic implants in my body was awful. But to think that I could end up going back to the insecure, self conscious person I’d been without my implants was just horrendous. There’s no way I could have carried on as a fetish model with a size A cup.'

Sophie Erhmann, 24, from New York, suffers from dermatillomania, a rare disorder that causes her to pick at her skin. She also suffers from trichtillomania, a similar condition that causes her to pull out her hair. Now, after keeping her illness a secret for a decade, Sophie has bravely revealed the extent of her illness in a harrowing exhibition.