Night Eating Syndrome

Health Effects of Night Eating Syndrome

File photo | Credit: First Light PsychOpens in new window Night eating syndrome (NES) is an eating disorder characterized by frequent intervals of night eating along with frequent sleep interruptions. People with the disorder feel like they won't be able to get back to sleep without eating.

Introduction

Night eating syndrome (NES) is a type of eating disorder related to eating after dinner and when awake at night. It was first discovered by Wolff, Stunkard, and Grace in a group of patients seeking weight loss treatment.

The syndrome was identified when their patients reported consuming a caloric intake of 25% or more at night during the time patients without obesity were not eating.

Etiology

The etiology of night eating syndrome has remained unknown. Recent research has proposed a link between a psychological course, neurological, and/or genetic processes.

A study by Lamerz and colleagues conducted on children in Germany showed that patients were more likely to develop night eating syndrome if their mothers had night eating behavior. These patients were compared to children of mothers who did not have night eating behavior.

A recent study compared night eating behaviors in families who had a person with the condition to those families who did not. The results showed that those with NES had first-degree relatives with the disorder more often than the control group suggesting a heritability aspect to the disorder.

Stress can exacerbate the symptoms of the disorder, and symptoms can be alleviated by decreasing stress levels. The initial onset and maintenance of the condition were shown by recent studies to be directly caused by stress and other psychiatric disorders like depression.

Epidemiology

In the United States, the prevalence of night eating syndrome is 1.5%. NES prevalence is similar to other binge eating disorders like bulimia nervosa and anorexia nervosa. It is more frequently seen in obese populations, although not all individuals with NES are, in fact, obese.

A study in Sweden revealed a 2.5 times more prevalence of NES in males with obesity along with a 2.8 times higher prevalence in females with obesity in comparison to non-obese of both genders.

A prevalence between 6 to 64% of NES was found among obese individuals looking for weight loss surgery in a review conducted by de Zwaan, Mitchell, Burgard, and Schenck.

A study showed up to 55% of individuals seeking bariatric surgery have reported some symptoms of NES. NES typically appears in the late teens to late twenties. NES also appears to be long-lasting, with relapse and remission tethered to stressors.

A Swedish twin registry participant in an interview-based study revealed more women than men who met all criteria for NES. It could suggest that both genders experience NES symptoms equally. However, females are more affected negatively. Those with night eating syndrome are more likely to have another eating disorder than the rest of the non-NES population, with a 5 to 44% prevalence.

Overlapping symptoms between NES and binge eating disorderOpens in new window have been shown as 15 to 20% of patients with NES also were found to have binge eating disorder. However, the conditions are differentiated by the quantity of food eaten per meal, the motivation for eating, and the concern about weight and shape.

Patients were recruited into a study by Lundgren from outpatient clinics using the NES screening questionnaire. Patients were asked about their evening food cravings, nocturnal ingestions, morning anorexia, and the sum of awakenings. The criteria for NES were met in 12.3% of the study participants, and it was found that those patients were also obese.

Pathophysiology

Researchers believe that cognitionsOpens in new window and a wide range of emotionsOpens in new window might play a major role in having NES. Most symptoms occur at night due to the belief that the individual cannot sleep without eating. Patients also will feel a need to control the anxiety associated with that belief through eating. Cortisol was examined during night eating as it is the hormone released during stress that is associated with overeating.

A study was done by Birketvedt and colleagues on 33 participants, 12 with NES and 21 control subjects. The subjects were fed regular intervals of meals over a 24-hour period and given no food after 8:00 pm. Blood tests were drawn every 2 hours over the 24-hour period, with the results showing higher cortisol levels from 8:00 AM-2:00 AM in night eaters compared to those in the control group.

History and Physical

Some studies have determined criteria to include hyperphagia in the evening with 25% or more of daily caloric intake after dinner with not less than two nocturnal awakenings during the week to eat food.

Additional criteria include the awareness of nocturnal eating habits and recall of the nocturnal eating habits. A clinical picture is described by three of these criteria:

1. Breakfast and/or morning eating are missed due to a lack of desire
2. The urge to eat between the evening meal and bedtime sleep
3. Difficulty initiating or maintaining sleep occurring for four or more nights per week
4. The belief that the individual must eat to return to sleep
5. The mood that worsens at night or is frequently depressed

Evaluation

In a randomized control trial done by Look AHEAD (Action for Health in Diabetes) study, the diagnosis of NES was found to be related to more patients with a depressed mood. The study also showed that diabetic individuals with obesity have higher BMI and reported weight problems at much younger life than those without eating disorders.

In previous studies, a significant predictor of HbA1c >7 was discovered in individuals with type 1 and type 2 diabetes that reported evening hyperphagia along with two or more diabetes complications and obesity.

Differential Diagnosis

Night eating syndrome is usually confused with sleep-related eating disorders. The main differential criterion between NES and sleep related-eating disorders is the nature and the component of nocturnal eating. While the NES is composed of both hyperphagia and nocturnal eating along with awareness, sleep-related eating disorders are mainly characterized by repeated involuntary eating habits during sleep. A sleep-related eating disorder is considered parasomnia due to involuntary and poorly recalled eating habits, along with nonfood items consumed, sharing similarities to sleepwalking.

Night eating syndrome can be classified as an insomnia-related disorder as patients are awake, aware, and able to recall their eating habits. Generally, patients with NES do not report underlying sleep disorders. However, some patients might report both syndromes.

Sharing the behavior of evening hyperphagiaOpens in new window between NES and binge eating disorder does not necessarily mean they share the same etiology. Unlike binge eating disorderOpens in new window, evening hyperphagia in NES patients is mainly correlated to nocturnal anxiety. In addition, the amount of food consumed in the evening in patients with NES is not as large (≈300Kcal) as in patients with binge eating disorders.

Prognosis

Patients treated for NES with pharmacological, cognitive therapy, and lifestyle changes have noticed a significant improvement in their symptoms. For those who are untreated, many health issues and emotional challenges are related to being overweight or having obesity, such as high cholesterol, diabetes, and high blood pressure.

Complications

Patients with NES commonly become overweight due to increased calorie intake before bedtime. The increased caloric intake results in complications such as diabetes, high blood pressure, cardiac disease, and obesity. Without psychotherapy, psychiatric disturbances can develop.

An association between NES and various psychopathologies, particularly depression, was found in most studies. Many patients with NES were found to meet lifetime criteria for major depressive disorders, MDD, substance abuse, and anxiety disorder.

Enhancing Healthcare Team Outcomes

Since most patients will not bring up issues with night eating either due to shame or guilt, it is recommended to use screening questions. The primary care provider should refer the patient to a psychiatric specialist for appropriate treatment. Patients with type 2 diabetes need to be screened for NES due to the high percentage of patients with pre-existing type 2 diabetes having clinical NES. After diagnosis, treatment should be followed by an interprofessional healthcare team that includes psychiatry, internal medicine, and endocrinology, working with nurses, pharmacists, and other mental health professionals.

Treatment

Psychotherapy has been shown to decrease night-eating symptoms. Twenty-five patients were treated with cognitive behavioral therapy by Allison and colleagues within 12 weeks of diagnosis. The interventional study included education, logging of sleeping and eating habits, encouraging coping skills, regulating eating and sleep patterns, and weight management. The study results showed reductions in weight gain, evening caloric intake, nocturnal ingestions, and recurrent awakenings at night. Treatment also showed improvements in mood enhancement and quality of life.

The serotonin system contributes to the regulation of eating, mood, and sleep. Therefore, it was assumed that reduced serotonin could lead to reduced satiety and circadian rhythm disturbances leading to an increased level of evening hyperphagia and nocturnal ingestions.

In a 12-week clinical trial study on 17 patients treated with sertraline, along with two additional studies that included randomized controlled trials, the results showed a massive reduction in night awakenings, evening hyperphagia, and calorie consumption after evening meals.

The rate for remission was 29%. However, the response rate was 67%. Open-label trial testing escitalopram efficacy revealed a significant reduction in NES symptoms, caloric intake consumed after dinner, and nocturnal ingestions; however, no difference was noticed in comparison to placebo in a randomized controlled trial.

In a randomized study on 44 patients from both genders divided into three groups: education, education plus Progressive muscle relaxation PMR or PMR plus exercise, Vander Wal and colleagues concluded there was the percentage of food eaten was significantly different between the three groups of study with the group doing PMR having the greatest reduction. The increase of postsynaptic serotonin has been proven using phototherapy. Two case studies used phototherapy to treat symptoms of NES and depression.

On a 51-year-old female with depression and NES, Freidman and colleagues conducted a study using paroxetine and bright light therapy. The results showed that discontinuation of the phototherapy made her NES symptoms return. The effect of bright light therapy was also studied on 15 patients with NES, and the results showed a tremendous reduction in NES symptoms along with mood and sleep disturbance after treatment.