From refugee children falling asleep for months or people having memory loss after hearing strange noises in the night - there still remain some remarkable diagnostic mysteries of the twenty-first century.
But what unites them is that they are perhaps examples of a particular type of psychosomatic illness: medical disorders that are influenced as much by the idiosyncratic aspects of individual cultures as they are by human biology.
So what are these illnesses, how do they occur, and how can we treat the people who develop them?
Dr Suzanne O'Sullivan, neurologist and author of ‘The Sleeping Beauties: And Other Stories of Mystery Illness’ joined Jonathan to discuss.