One autumn day roughly two years ago, a young woman was brought into Ryan McKay's office at a London hospital, sobbing bitterly, clearly very distressed and upset.

At that time, McKay's job was to administer specialised psychological tests to people who had been admitted to the hospital, to help provide neurologists with a better picture of their patients' brain functions. The woman, who we'll call Liz, was in hospital to seek help with serious and prolonged epileptic seizures, but when she was wheeled in to see McKay that morning, she was obviously suffering something much more disturbing.