Switching Time

One afternoon in 1989, Karen Overhill walks into psychiatrist Richard Baer's office complaining of vague physical pains and depression. Odder still, she reveals that she's suffering from a persistent memory problem. Routinely, she "loses" parts of her day, finding herself in places she doesn't remember going to or being told about conversations she doesn't remember having. Her problems are so pervasive that she often feels like an impersonator in her own life; she doesn't recognize the people who call themselves her friends, and she can't even remember being intimate with her own husband.…