Recognizing Night Eating Syndrome

If you or someone you know suffers from Night Eating Syndrome (NES), you know how disruptive and distressing it can be. NES is a disorder that features difficulties in eating, sleep, and mood. Unfortunately, much of the public and many healthcare providers do not know what NES is or how to identify and treat it.

NES is characterized by a delayed shift in the circadian pattern of eating. On average, sufferers eat a third of their daily food intake after the evening meal. Typically, someone with NES will feel compelled to eat until bedtime, believing that he or she will not be able to initially fall asleep without a full stomach. They then wake up about 90 minutes to 2 hours later feeling compelled to eat more in order to fall back to sleep. If eating this snack is resisted, they will likely toss and turn, feeling restless, agitated, and unable to sleep. Many sufferers struggle with this type of pattern for years.

NES sufferers often have trouble falling asleep and staying asleep throughout the night. In studies at the University of Pennsylvania School of Medicine, we use both polysomnography (sleep studies) in the hospital and wrist motion sensors in the home environment to monitor sleeping patterns. Our research team has shown that people with NES have similar bedtimes and morning rise times as people who do not have NES. However, their sleep is less efficient and less restful due to frequent awakenings. Thus, NES seems to be an eating disorder that secondarily affects the quality of sleep.

Persons with NES often report having a depressed mood that worsens later in the day. Additionally, half of our study participants experienced a major depressive episode at some point in their lives, compared with only 18 percent of controls. We also found that they reported more depressive symptoms at the time of the study, even if they did not meet criteria for clinical depression at the time. Thus, NES seems to be a multifaceted disorder, with aspects of eating, sleep, and mood problems.

NES does not appear to discriminate by gender or race. Men and women are almost equally affected, and both African Americans and Caucasians are likely to suffer from it (other ethnic and racial groups have yet to be studied). The average age of onset, 30 years, is later than for other eating disorders, such as anorexia nervosa and bulimia. NES usually begins after a stressful event, such as the loss of a job, a difficult pregnancy, or with the treatment of substance addiction. However, some sufferers begin in their early teens without a specific reason.

Other evidence that NES is a stressrelated disorder is shown in elevated salivary cortisol levels, a hormone that is linked to reactivity to stress. Study participants with NES also report experiencing more subjective levels of stress than control participants. Genetics plays a part in this disorder; a third of our study participants report that other members of their families suffer from NES as well. We are currently in the process of investigating possible genetic links.

Treatment studies of NES are underway but are still in their infancy. An open-label study with the selective serotonin- reuptake inhibitor, sertraline (Zoloft) was promising, with over half of the participants decreasing their night eating symptoms by at least half. A controlled trial with this medication is underway. Since NES interferes with the regulation of both sleeping and eating, and since serotonin regulates both of these functions within the brain, it seems natural to try treating NES with this type of medication.

A cognitive-behavioral therapy treatment for NES is also currently being tested. This treatment uses the basic components of CBT as applied to other eating disorders and obesity treatment, adding specific focus on the link to thoughts during the evening and night when night eaters feel the least amount of control over their eating. A brief model of progressive muscle relaxation from a group at the Medical University of South Carolina has been shown to decrease some aspects of NES as well.

Other drug treatments and approaches, such as phototherapy, have been reported, but more research is needed to understand this complex disorder and help its many embarrassed and distressed sufferers. The good news is we are learning more every day.

Kelly C. Allison, PhD, is a clinical psychologist at the University of Pennsylvania School of Medicine’s Weight and Eating Disorders Program. Her work focuses on the psychological aspects and treatment of eating disorders related to overweight and obesity.