Hal Droogleever Fortuyn, M.D., of Radboud University Nijmegen Medical Center in the Netherlands, and colleagues just published a study uncovering severe binge eating problems in people with narcolepsy, a sleep disorder. Half reported runaway cravings for food and binge eating. More extreme, almost a quarter (23.3 percent) met the criteria for a clinical eating disorder.

The findings are stunning, first in their numbers.

•Of the 60 narcolepsy patients surveyed, 67 percent reported an irresistible and persistent craving for food -- versus only 5 percent of the 120 controls.

•A whopping 55 percent of narcoleptics engaged in binge eating --versus a scant 1 percent of controls.

While it’s clear that there is a connection between sleep and appetite, questions remain. What exactly is it? And what can the rest of us non-narcoleptics take home as a message?

On a molecular level, the link between sleeping and eating uncontrollably is all about a neurotransmitter called orexin (a.k.a. hypocretin), discovered in 1998. While trying to find a good target for an obesity drug, researchers stumbled upon orexin (and its receptor) – both located in a region of the brain called the hypothalamus, which controls appetite.

Dogs and mice that bear mutations in their orexin receptors eat less, showing that the molecule plays a role in stimulating appetite. But the mutant animals also develop a bizarre form of narcolepsy, characterized by floppy “sleep attacks,” called cataplexy, that come on unbidden. (Check out Skeeter “the narcoleptic poodle” to see what narcolepsy looks like.

In humans, narcolepsy is a bit different, characterized by a huge variation in symptoms, everything from sleepiness all day long to dropping over like a rag doll at unpredictable moments.

If that isn’t enough angst, there is something more.

Narcolepsy patients tend to be overweight, “some heavily overweight,” says Droogleever Fortuyn. “Sometimes they have candy with them -- and offer me some. It wasn’t very difficult to think that there might be a connection.”

Indeed, he found one. And now Droogleever-Fortuyn is advocating for more attention to eating disorders in the treatment of patients with narcolepsy. They are already slogging through inconceivable setbacks from severe their sleep disturbances. How much worse to shamefully—and thus quietly—suffer from the symptoms of an untreated eating disorder?

While physicians and therapists can keep this in mind when treating patients with narcolepsy, there is a larger message for the vast majority of us who do not suffer from the sleep disorder.

Eating and sleeping are intimately, molecularly connected.

The narcolepsy patients were not binging to find pleasure through food in the midst of suffering a debilitating disease. Instead, the bingeing stemmed from biological roots. The same molecular pathway that influences sleep patterns and muscle tone also affects appetite. If you don’t believe this, just take a lesson from people’s experiences with the sleep drug, Ambien. Many of the drug’s users began sleepwalking into their kitchens and stuffing down thousands of calories of food. Why? The drug targets a still-mysterious circuit in the brain that links the primal acts of eating and sleeping.

We can all take a lesson from the extremes. While binge eating disorder and narcolepsy represent the severe end of the disordered eating and sleeping spectrum, they both point to a biological connection worthy of further study. To wit, we all aspire to sound sleep and healthy eating.