The idea of repressed memory - when traumatic events are wiped from a person's conscious memory but resurface years later - has had a chequered past. Some have cited it as evidence in court, yet others dismiss it as nothing more than psychiatric folklore.

A new study adds a literary layer of evidence to the debate. To see how long the idea of repressed memories have been around, a group of psychologists and literature scholars turned to historical writings.

They could not find a single description of repressed memory, also referred to as dissociative amnesia, in fiction or factual writing before 1800.

Harrison Pope of Harvard Medical School in Boston, Massachusetts, and his colleagues harnessed the power of the Internet to gather information, advertising on more than 30 websites and discussion boards a US$1,000 prize to the first person who could find an example of repressed memory after a traumatic event in a work published before 1800.

If such cases existed, they reasoned, then throughout history, individuals would have witnessed them and written about them in the literature of the time. Other psychological phenomena, like delusions or dementia, have been documented across the ages in this way, with no particular date at which the condition suddenly emerges.

But although more than 100 people replied, they came away empty-handed. There were "a number of near misses", Pope says, such as King Dushyanta, a character in a 4th century play by the Sanskrit poet Kalidasa who forgets he was in love with his wife Shakuntala as a result of a curse. But this example doesn't qualify, says Pope, as the memory is not of a distressing event.

Cultural sensitivity

Writing in the journal Psychological Medicine1, the team suggest that repressed memories are not a neurological reality, but a cultural invention from the time when Freud's theories of the unconscious mind took hold of nineteenth century psychology. "I'm reasonably confident that if there were a case, it would have surfaced," Pope says.

The idea of trawling the historical literature for examples occurred to Pope as he read Rudyard Kipling's 1897 novel, Captains Courageous, to his children. The main character develops amnesia after losing his family in a flood, but a later event suddenly brings the memory back.

Other psychologists are less certain about the technique. Repressed memory is a strategy usually seen in children trying to cope with abuse, says Chris Brewin, a psychologist at University College London. The focus of literature might have been on adults, he notes - the wrong place to pick up these experiences. And not finding examples doesn't necessarily mean that the condition wasn't there.

Total recall

Could literature searches along similar lines help to demystify disputes over other psychological conditions? "The technique would apply only to things that are easy to recognise," Pope says. It would not be so straightforward, he adds, to look for things with non-specific symptoms, such as attention-deficit-hyperactivity disorder (ADHD) or autism.

Pope is quick to add that their findings don't mean that the condition doesn't need treatment. Even things with no biological basis need to be dealt with, he says.

But the idea that it is not a neurological disorder does have implications for legal claims, he says. He warns that people who feel they have remembered repressed memories may not be recalling real events.