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It’s an astonishingly common dream. Many of us have it, with numerous reruns throughout our lives.

“I never went to class. I never did the work. I never studied. Final is tomorrow. Terrible anxiety,” says Susie Drucker Hirshfield, 71, of Stockbridge, Mass., a friend from college. “Or, I’m a freshman. The campus is huge. I’m lost. I can’t find my classroom building. Seems like I walk around forever, and never find it. Or I find it, and the class is over.’’

Ben Goldberg, 28, a lawyer who was an A student of mine in the Philip Merrill College of Journalism at the University of Maryland, has his own version. “I wake up the morning of a final and realize I am completely unprepared for the exam,” he says. “I spend the day frantically trying to learn the material, but still walk into the exam hopelessly unprepared. Or I wake on the day of the final and realize that I’ve cut the class all year.”

(Since I don’t give final exams in my classes, I’m sure his dreams have not been about me.)

It’s a dream that apparently spans the generations and usually involves high school or college, sometimes both. And, oddly, it seems to haunt us decades after we last sat in a classroom.

For most people, including me, it goes like this: We’ve signed up for a course that we never attend, or we forget we enrolled in it. When final-exam day approaches, we are panic-stricken because we never went to any of the lectures, never took notes and never did the readings or assignments. (In one bizarre twist, some people report that they show up on final exam day naked — perhaps feeling vulnerable?)

For some, the course is one in which we did poorly in real life. Others dream of a subject in which they actually did well but had worried about failing.

“I’ve had these dreams during and since college,” Hirshfield says. “I even have them when I am not anxious about anything. It’s one of those universal dreams. I think everybody has them.”

I think she’s right. But why is the dream so common? I couldn’t find any research on the topic — surprising, because the dream seems like natural fodder for psychologists. I talked to a few experts who also were unaware of studies examining this dream. In the absence of peer-reviewed findings, however, they were willing to offer a few thoughts, stressing that their ideas were nothing more than opinion and speculation.

“I think those who have it tend to be professional and were successful students,” says Judy Willis, a neurologist and teacher who lives in Santa Barbara, Calif., and who wrote about the dream in a 2009 Psychology Today blog post. “These are people who have demanded a high performance from themselves. The recurrence of the dream correlates with times of stress and pressure, when people feel they have a challenge to achieve.’’

Gemma Marangoni Ainslie, an Austin psychoanalyst, agrees. The final exam, she says, “is likely representative of an occasion when the dreamer feels he or she will be tested or measured, and the anxiety is about not measuring up. The dreamer’s task in ‘awake life’ is to translate the final exam to a situation he or she is facing that stirs up concerns about potential failure.”

But why school? Why don’t we dream about current pressures — grant proposals that are due, impending legal briefs or oral arguments, or newspaper deadlines?

“Emotional memories and impressions made during high-stress experiences are particularly strong, and are further strengthened each time they are recalled and become the place the brain goes when the emotion is evoked,” Willis wrote in an email. “Since each new stress in the current day is ‘new,’ there is not a strong memory circuit that would hook to it in a dream. But there is that strong neural network of previous, similar ‘achievement’ stress. Since tests are the highest stressors. . . [it] makes sense as the ‘go-to’ memory when stressed about something equally high stakes in the ‘now.’ ’’

Ainslie theorizes that most of us have these dreams “as an attempt to disguise what it’s really about,” she says. “The part of yourself that is distressed wants to disguise it, and the easiest way to disguise it is to move backwards.”

Ainslie says the school dream is a common one, although it’s not the only one that reflects anxiety. “Another common one is being in a car and not being able to put the brakes on,” she says. “This one isn’t about not measuring up. It’s about not being in control, a matter of not being the driver in your life.”

Alma Bond, a retired New York psychoanalyst and writer, describes the school dream as a response to “an unconscious memory of an experience for which we were totally unprepared,” adding that it’s possible “we unconsciously remember a time when we did fail some test or other, and are afraid we will repeat the failure.”

My son, 26, is the only person I know who claims never to have had this dream, and he has a plausible explanation as to why. A serial class-cutter in high school, he says that “skipping classes has always seemed normal to me.”

But those of us who are Type A personalities — as well as anyone else with achievement-related stress — may be fated to have this anxiety-producing dream over and over.

Ed Hershey, 72, of Portland, Ore., who spent most of his career in academic communications, recently posted on Facebook of yet another “vividly familiar,” periodic, “I-won’t-graduate-from-high-school-on-time” anxiety dream. He noted that it struck just a few weeks before his 55th high school reunion.

Forty-seven “friends’’ responded, and a dozen of them posted examples of their own variations on the dream. “I guess they [the dreams] never stop, do they?” he says, adding: “At least I know I am not alone.”