‘Unremembered Night Eating Syndrome’

Two studies explore unusual night eating.

Nighttime food intake is often linked to weight gain and obesity. In most cases, night eaters are able to recall their nighttime eating sessions, although these are usually kept secret. However, in some cases, the night eater has no memory of the nighttime eating binge, and has what  Dr. Kentaro Yamada at Kurume University School of Medicine, Kurume, Fukuoka, Japan, and colleagues term the “unremembered night eating syndrome (Endocrine Journal 2013 [published online ahead of print]). The authors identified 9 patients who experienced the unremembered nocturnal eating syndrome (UNES); 6 of these patients had significantly higher HbA1c levels.

The Kurume Sleep Trouble in Obesity and Metabolic Disorders (KUSTOMED) study is a multicenter cross-sectional observational study on the quality of sleep and phase-shift in circadian rhythm in obese and/or diabetic patients. Among the 1,224 participants in the KUSTOMED study, 1,169 were diagnosed with diabetes. The authors identified 9 patients (3 men and 6 women) who had experienced UNES. Six were treated with insulin and 2 others with oral hypoglycemic agents, including sulfonylureas. These patients had eaten snacks, bread, rice, sausages or yogurt after the onset of sleep, and had no memory of doing so. They realized they had eaten the foods only after they found them missing or family members witnessed their eating behavior at night.  The nocturnal eating sessions occurred from once a month to almost every night.

The authors found a significant association between the unusual nocturnal eating disorder and use of hypnotic drugs. The prevalence of UNES was 0.8% in all subjects, and but 4% in those taking hypnotic drugs; another factor was higher (BMI mean: 30.1 kg/m² vs. 24.4 kg/m² among patients without the night eating syndrome).

A case of serious night eating syndrome and a promising agent

In a separate study in Italy, Dr. Walter Milano and colleagues reported the case of a NES patient successfully treated with agomelatine, an antidepressant analog of melatonin (Case Reports in Medicine 2013; published online ahead of print]). Melatonin is the naturally occurring hormone that regulates the body’s circadian rhythms that control the biochemical, physiologic and behavioral 24-hour cycles involving sleep and many functions as well. According to the authors, emotional factors such as depression, anxiety, stress, boredom, low self-esteem, and skewed body image play a significant role in NES and are catalysts that lead to night bingeing on high-calorie “comfort foods.”  Patients with NES often have higher-than-normal scores on the Beck Depression Inventory and the Zung Depression scale, compared with controls.

Dr. Milano and colleagues reported the case of a 39-year-old woman with a 5-year history of night eating syndrome (NES). She reported frequent awakenings associated with consumption of food, especially sweets and snacks, followed by a markedly decreased appetite during the day and a hearty evening meal. During the 5 years she had gained about 26.7 lb (12 kg), and her BMI rose from 23.5 to 28.0.  For about 2 years she used antidepressant therapy, first with venlafaxine and then sertraline. While her mood improved considerably, the nighttime awakenings and episodes of nocturnal feeding remained nearly unchanged.

In January 2011 the patient stopped taking sertraline and 3 months later began treatment with 25 mg/day doses of argomelatine. After 10 days, this dosage was increased to 50 mg/day. When she started on the new therapy, she had a score on the Night Eating Questionnaire (NEQ) of 38, and 20 on the Hamilton Depression scale (HAM-D), and awoke to eat about 4 times per night. After 3 months of treatment with argomelatine, the patient’s nocturnal awakenings had fallen to an average of 2 per night. The NEQ and HAM-D scores were significantly reduced, to 25 and 9, respectively. After 3 months, her weight fell to 64.5 kg (142 lb) and a BMI of 26.