THE evening meal is over, the dishwasher stacked, and yet often there’s that irresistible urge for a small snack as you put your feet up in front of the television.

But around one million people in the UK with night eating syndrome (NES) do not stop at a snack. They go on to consume a third or more of an entire day’s calories — mainly carbohydrates — all over again. Driven by hunger pains, they often continue to raid the refrigerator throughout the night.

In the past NES, which affects men and women, was dismissed as simply greed, but it has now been acknowledged as a clinical disorder — and one which, research suggests, is treatable. At the recent conference of the North American Association for the Study of Obesity, psychologists from the University of Pennsylvania’s weight and eating disorder centre unveiled their latest findings from a study investigating ways to control the syndrome.

Dr Kelly Allison reports that treatment with the antidepressant drug Zoloft, combined with strategies such as cognitive behavioural therapy to change eating and exercise patterns, appears to be effective. In around 50 per cent of cases, she says, “patients reported a major depressive episode at some time in their life”, such as redundancy, divorce, childbirth or the menopause and stress, with the disorder, which is why Zoloft appears to be helpful.

In another smaller study funded by the US National Institute of Health, the Pennsylvania team found that a third of night eaters experienced total remission of NES with Zoloft and 18 per cent reported significant improvements. On average, says Allison, the number of calories consumed after supper dropped by 40 per cent. She emphasises, however, that “while we got good results with the drug, it’s not a magic bullet for everyone” and that further research is required into other forms of medication.

Though being overweight is a common side-effect of NES — 6 to 8 per cent of people who are treated for obesity claim to or suffer from NES — it also affects 1.5 per cent of the general population, many of whom manage to maintain a normal weight. No one is sure of the precise cause of NES, but it is thought to be linked to disturbed body rhythms. Professor Alerbt Stunkard, who discovered NES in the 1950s, says that while circadian sleep patterns remain the same, it is the “circadian rhythm of food intake that appears extremely disturbed and the timing of eating delayed by four to five hours compared with that of normal people”.

Hormones are also thought to be implicated. Levels of melatonin — the sleep hormone — are significantly reduced in NES sufferers and leptin — an appetite suppressant — didn’t rise to normal levels in night-eaters, suggesting that their hunger pangs may be extreme enough to disturb sleep. Meanwhile, cortisol — often called the “stress hormone” — appears elevated at night in people with NES, perhaps forcing them to wake up. Dr Grethe Stoa Birketvedt, a research professor at Mount Sinai School of Medicine in New York City, believes there is also a hereditary component.

Unlike other nocturnal sleep-related eating disorders in which sufferers claim to be asleep when they get out of bed to binge, those with NES are fully aware of their actions. “They are not sleepwalking, but there is a feeling of compulsion and anxiety associated with it,” Allison says. “The eating helps to soothe them and makes them feel better for a short time, but it can also increase their weight, which makes them feel worse. And their delayed patterns of eating can affect their ability to concentrate at work the next day.”

For some it becomes an emotional and physical cycle that is difficult to break — the Pennsylvania researchers have subjects who are in their sixties and have suffered NES for 30 years.

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