Nightmares Are Good for You, According to Scientists

And what experts think they mean

Tessa Love
Published in
6 min readJan 14, 2020


Photo: Gabriele Vilkaite / EyeEm/Getty Images

WWhether you’re a restful or restless sleeper, you’ve likely had the experience of waking up at night in a cold sweat, heart pounding with fear, only to sigh with relief when you realize that person chasing you down a dark alley was just a figment of a bad dream.

Dreams disturbing enough to startle you awake are common. According to the American Society of Sleep Medicine, up to 85% of adults experience occasional nightmares, which are the American Psychiatric Association defines as powerful, unpleasant dreams that elicit feelings of threat, anxiety, fear, or other negative emotions. Nightmares, according to the definition, are also clearly recalled upon awakening, and the majority are completely harmless.

Nightmares are generally considered a normal, if slightly harrowing, aspect of sleep. But the prevalence of nightmares brings up a lofty question: Is there a reason our mind puts us through these frightening scenarios?

Dream experts believe the answer is yes, nightmares do serve a purpose. And though there’s no single, united theory as to what that purpose might be, research is increasingly showing that nightmares could help people better navigate their waking lives.

Bad dreams could actually help reduce anxiety around real-life situations by acting as emotional dress rehearsals.

“Dream content goes in repetitive circles the same way our waking thinking does. Everything you’re thinking about or striving for while awake tends to show up in this state that is more metaphoric, more visual, less verbal,” says Deirdre Barrett, PhD, a professor at Harvard and author of The Committee of Sleep: How Artists, Scientists, and Athletes Use Dreams for Creative Problem-Solving — and How You Can Too.

Nightmares, Barrett says, are the mind’s way of “anxiously anticipating bad things and trying to think of what to do.”

Many experts — Barrett included — believe that nightmares developed as a neural response to the threats posed by life before locked doors, streetlights, and social order. Remembering that the village over the hill could attack or a…