—Photo-Illustration by TIME (Source Image: Jackyenjoyphotography/Getty Images; Don Mason—Getty Images; BraunS/Getty Images; skaman306/Getty Images)Some years ago, a young woman arrived at a clinic in Redwood City, Calif., for surgery. She’d been attacked with a knife in her home twelve days before, and she was there for reconstructive work on her hand. As she told her doctors about the attack, she broke down in uncontrollable sobs. After surgery, however, when she woke up from anesthesia, she was happy and relaxed, says anesthesiologist Dr. Harrison Chow, who was part of her care team. While she was under, she had dreamed of being attacked. People who have had traumatic experiences often have nightmares about them. But this time, unable to wake up because of the anesthetic, this patient continued dreaming: She dreamed of going to the ER, having surgery, and then returning home and being back to normal. Waking up, she felt “wonderful,” she said. A follow-up with a psychiatrist suggested that before the surgery, she’d met the criteria for acute stress disorder, which is similar to PTSD. Afterwards, she did not. And she wasn’t the only one of Chow’s patients to have this experience.Doctors have known for decades that sometimes people dream while under anesthesia. For the most part, doctors have thought that such dreams were not beneficial, worrying that they might be linked to an increased risk of waking up during surgery. But now, researchers are beginning to explore whether anesthesia dreams might be able to help resolve traumatic experiences, and whether—even for people without trauma—they might make surgery a more pleasant experience. In a recent pilot study in Anesthesiology, Chow, who is at Stanford University Medical School, and his colleagues report that a protocol intended to help patients dream during surgery is a feasible addition to standard of care. In this study, in which the protocol was used in hundreds of surgeries, the team didn’t find that dreaming correlated with less pain or anti-nausea medication afterwards, but they did find that anesthesia-induced dreams were very common and overwhelmingly positive, suggesting that dreaming could improve the experience of surgery.It’s not difficult to induce dreaming under anesthesiaDreams during natural sleep are not necessarily positive. In fact, they’re “often somewhat negative,” says Karen Konkoly, who studies dreams at the University of Cambridge in the U.K. and was not involved in the new study. But in this paper, 86% of the dreams recalled by patients on waking were good ones—a finding she calls “super interesting.”What’s more, nearly 70% of patients who were primed to dream under anesthesia reported dreaming when they woke up, without a particularly complex protocol. First, patients who were receiving surgery were simply told that they might dream while under anesthesia. Then, they were given an anesthetic cocktail including the drug propofol, and their brain activity was tracked with EEG to monitor their level of sedation. Finally, after surgery, patients were given 10 minutes to wake up naturally and were asked immediately upon waking whether they had dreamed. The 10 minutes of peace were the only part of the protocol that doctors in the study mostly didn’t follow. “Surgery,” says Chow, “functions like Southwest Airlines.” Most patients were awakened swiftly to clear space in the recovery rooms for the next patients. Still, the positive effects held. Pilleriin Sikka, a researcher at Stanford and an author of the paper, hopes that with such a low-effort prompt, it may be possible to run other experiments investigating whether dreaming under anesthesia can help with patient satisfaction after surgery, and whether it can help patients better recover from trauma. Can dreaming under anesthesia be therapeutic?There are signs the answer may be yes. “With nighttime dreams, we don't know what they do,” says Konkoly. “Messing with them is useful for understanding what they do, and potentially helpful when dreams go awry.” Anesthesia dreams, however, are happening in an artificial setting, she says, and inducing them and potentially manipulating them may have more in common with psychedelic therapies for PTSD, which are a subject of active research, than with manipulating dreams during natural sleep. Dr. Boris Heifets, one of the paper’s authors and a professor of anesthesiology at Stanford who also studies psychedelic treatments, agrees. “Every paper that's written about psychedelic therapeutics, you have this intense period of a psychoactive, non-ordinary state of consciousness, and then something changes, and people are better,” he says. When Heifets first met Chow and learned of his patients’ experiences, “the parallel was so clear.” One breast cancer patient Chow wrote about in another study, who suffered from PTSD after the death of her son, felt her dreams during her surgery “saved her life.” “It still kind of gives me shivers thinking about what these patients have said,” Heifets reflects. Going forward, the team hopes to use the protocol to explore dreams in PTSD patients more systematically. “The frontier is seeing how far this goes—if you can induce these dreamlike states and really make for transformative events in people's lives,” Heifets says.