Imagine regularly waking up exhausted, not because you didn’t sleep, but because you seemingly spent the entire night immersed in incessant dreams. For people who experience such “epic dreaming”, the effects can be severe, often impacting their work and day-to-day lives.

“These vivid experiences linger in my mind, drain my energy and create lasting fatigue,” said one such epic dreamer.

This woman, identified as 38-year-old Madame R, is one of four epic dreamers who have been assessed at two centres in France. Though scientific descriptions of epic dreams date back more than 20 years, the four detailed case studies support the idea that it should be recognised as a distinct sleep disorder, according to the researchers, who included Pierre Geoffroy at Paris Cité University.

During her assessment, Madame R said she has always experienced epic dreaming, but it worsened after the birth of her second child. The other case studies include Monsieur W., a 74-year-old man who said his intense, vivid dreams are “at times indistinguishable from reality”.

Then there’s Monsieur D., a 58-year-old man who reported four years of twice-weekly excessive dream activity, and Madame W., a 40-year-old woman who can’t remember a time without it. “It feels like my brain never stops at night,” she said.