Over the years movies, prime time television and, of course, soap operas have used amnesia as a major plot device, jarring characters out of their former lives and leaving them unable to remember who they are, where they come from and how they have found themselves in their present state. But how close is this Hollywood depiction of memory loss to real-life cases? Why does amnesia happen, how common is it and can someone eventually recover?

There are many types of amnesia, and many reasons these can develop such as head injury, disease, drugs or psychological trauma. Retrograde amnesia is where the sufferer has difficulty remembering events that happened before the onset of amnesia. Anterograde amnesia, where new events and experiences fail to be stored as long term memories, and transient global amnesia is characterized by a short term loss of the ability to put down new memories, and difficulty accessing old memories.

"When I actually talk about this in class I like to jokingly call retrograde amnesia 'soap opera amnesia' because for the most part this is the Hollywood version that you're thinking about," says Steve Joordens, a professor of psychology at University of Toronto Scarborough. "I think storytellers love it because it gives them a freedom of expression and viewers love it because it creates situations of interesting conflict that should be unreal but are seemingly medically plausible."

The difference between reality and fantasy
And, though we have often seen retrograde amnesia played out in films like The Bourne Identity and The Majestic, in truth Joordens says this type of across-the-board memory loss is very rare, particularly for extended periods of time.

"In most cases, the memory will be spotty, and there are things they won't remember and things they will remember,” he says. “It's not like movies where it's all or nothing."

Dr. Myriam Mongrain, a psychologist at York University, says she can understand the appeal of putting stories about amnesiac disorders, memory disorders and identity disorder on screen, but says the problem is that there are often so few actual known cases out there that actors and writers take creative liberties, and audiences then start believing these are credible portrayals of something rare.

"I don't think the depiction comes close to the clinical reality," she says. "It happens in so few people, so it's not likely that your neighbour or bank teller has it."

Page 1 of 2--On page 2: Recovering lost memories

Joordens says that for many sufferers of retrograde amnesia, which often results from a concussion, memory tends to return as the brain recovers. However, in cases of damage due to drug abuse, severe brain injury and diseases such as Alzheimer's, sometimes the memories can never be retrieved.

"If you know anybody who has had a serious accident, even years after they may tell you they can't remember the two or three minutes just prior to the accident, and sometimes people never get that back," he says. "But usually what happens when anybody has a serious concussion is they wake up and they're missing some days before the accident, and then slowly the past sort of comes creeping back in as brain tissue stops swelling, the brain starts to work better."

He says that in cases where a patient is having difficulty recovering their memory, therapies like taking a patient back to a familiar setting that can jog their memory, and as each memory is recovered it can serve as a cue for retrieval of the next.

Emotional shock and amnesia
Dr. Mongrain adds that those who may be suffering from retrograde amnesia due to severe emotional shock can also recover their memories, but the timeline can be extended if the patient isn't ready and willing to address the issues surrounding the original trauma.

"If there's no brain damage, no damage because of the serious abuse of substances and no physiological reason, then they likely could retrieve their memory," she says. "In cases like this you retrieve the memory when you're ready, and that can take years. But with the help of a good therapist that can happen sooner."

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