As on many evenings before, Jane Doe, a businesswoman in her mid-20s, arrived home from a frenetic day at the office. She poured herself a glass of soothing red wine, put on her favourite Bach CD and sat down to enjoy the evening paper. Suddenly, a wave of anxiety passed over her.

Within the space of a couple of minutes, Jane suffered from a pounding heart, shortness of breath, chest pain, numbness in her fingers and toes and uncontrollable shaking.

She believed she had had a heart attack and rushed off to the nearest emergency clinic. The doctor could find nothing wrong and, after a couple of days, Jane dismissed the incident as a stress attack caused by long hours spent at the office.