A fairly rare eating disorder whose signature is excessive eating - though not necessarily binging - at night needs further study since it may signal other mental health issues, researchers say.
They analyzed eating disorders and mental health history in more than 1,600 university students and found about 4 percent met night eating disorder criteria, with about a third of those also engaging in binge eating.
"Night eating syndrome is characterized not only by eating at night - certainly many college students might have a late night study fest with eating - but it's also characterized by other things, like feeling that you can't eat in the morning, and feeling like you have to eat in order to go back to sleep," Dr. Rebecka Peebles told Reuters Health.
Peebles, the study's senior author, is an attending physician at the Children's Hospital of Philadelphia, and a researcher in the department of Pediatrics at the Perelman School of Medicine at the University of Pennsylvania.
"Our study helped extend findings of previous studies that have not been controlling for binge eating," Peebles said. "We know that binge eating and night eating have a pretty moderate overlap so a lot of people who come into the clinic for night eating often have binge eating."
"We think night eating is something to be aware of even though it only occurs in just under 3 percent of the students after controlling for binge eating, so it's still a pretty important entity," Peebles said.
Distinguishing night eating from binge eating is important, Peebles and her colleagues write in the Journal of Adolescent Health, for several reasons. Night eating may require a different treatment approach than other eating disorders, which could also be present.
Night eating was also more common in students with a history of anorexia nervosa and in students taking ADHD medications, they report, so those other disorders may play a role in the nighttime eating syndrome.
Night eating disorder is a distinct diagnosis in the newest psychiatric Diagnostic and Statistical Manual (DSM-5), the researchers note.
The syndrome is often characterized by increased appetite at night, but usually takes the form of "grazing" on food