Amnesia: is it for real? Recent movies like 50 First Dates probably have you wondering about memory loss. Forget most of what you have seen.(What You're Dying To Know About)

* Memory loss seems to be the hot topic onscreen, with Drew Barrymore putting Adam Sandier through 50 First Dates (in the flick, she suffers from a rare condition in which she wakes up every morning with amnesia) and Jim Carrey blotting out painful memories of his ex in Eternal Sunshine of the Spotless Mind. And this month, Matt Damon returns in The Bourne Supremacy, about a hunky secret agent with one teensy problem: He can't remember who he is.

All of which leave you, the viewer, sitting there in the dark, looking up at the screen and asking yourself, Could that ever happen to me?

Don't Believe What's on the Big Screen

The reality is that everyday people really do lose their memories, say experts. But while amnesia makes for high Hollywood suspense, in the real world, memory failure is pretty uncommon and, when it does occur, far more mundane. "In the movies, amnesia is shown in a very sensationalistic way," says Lawson Bernstein, MD, assistant professor of psychiatry at the University of Pittsburgh School of Medicine. "But those portrayals don't have much basis in fact." While complete anmesia (the wiping out of a lifetime of stored memories) can and does occur, it's almost unheard of, Dr. Bernstein says.

Clinically, amnesia is defined as memory loss--short- or long-term--and can be caused by a variety of factors, from brain damage, illness, or shock to drugs, alcohol, stress, or the always cinematically popular blow to the head. The common thread running through all of them is that each factor, in some way, attacks the hippocampus, a ridge alongside each lateral ventricle of the brain that processes memories. But how amnesia typically manifests itself has been--surprise!--wildly exaggerated by Hollywood.

Exhibit A: secret agent Jason Bourne, who's had his memory wiped out thanks to a nasty head injury and bullet wounds. While that could indeed lead to permanent memory loss, Dr. Bernstein says Jason would be in no shape to run around the world chasing bad guys. "Anyone who suffers that kind of severe brain trauma would not be mining back and functioning like a secret agent," says Dr. Bernstein. "He would have serious motor impairments that would hamper his performance."

And pixieish Lucy Whitmore, who makes poor Adam Sandler win her heart over and over and over in 50 First Dates? The daily memory loss she experiences (in the movie, it's the result of a car accident) is pure fiction. The closest thing to it is Alzheimer's, the degenerative, memory-robbing disorder that effects an estimated 4.5 million people in the U.S., almost all of them over the age of 60.