Nocturnal Sleep-Related Eating Disorder (NSRED) is a complex condition that uniquely combines aspects of both a parasomnia and an eating disorder. It falls under the category of non-rapid eye movement (NREM) sleep parasomnias, specifically described as a type of sleepwalking. This disorder involves behaviors connected to a person's conscious desires or wants, often manifesting as the fulfillment of suppressed conscious wishes. However, distinguishing
NSRED from other similar disorders can be challenging due to its multifaceted nature.
Classification and Core Characteristics
NSRED is classified within somnambulism, or sleepwalking, indicating that the eating behaviors occur while the individual is in a sleep state. The International Classification of Sleep Disorders-Third Edition (ICSD-3) includes dysfunctional eating during the main sleep period, consumption of unusual or toxic foods, and negative health consequences as diagnostic criteria. A key differentiating factor for NSRED is that the affected individual is typically not conscious during these eating episodes and will have no memory of them the next morning. This lack of awareness is crucial in distinguishing it from other conditions.
This disorder is often referred to by other names such as Sleep-Related Eating Disorder (SRED), sleep eating, or somnambulistic eating. While primarily considered a parasomnia, its symptoms also align with those of eating disorders, particularly binge eating. The combination of these elements makes NSRED a unique challenge for diagnosis and treatment, requiring specialists in both psychiatry and sleep medicine to address its various components.
Distinguishing NSRED from Night Eating Syndrome
One of the most important distinctions in diagnosing NSRED is differentiating it from Night Eating Syndrome (NES). While both involve nocturnal eating, the level of consciousness during the episodes is the primary difference. Individuals with NES are fully awake and aware of their eating and bingeing at night. In contrast, those with NSRED are asleep and completely unaware of their actions, often having no recollection of the events upon waking.
Dr. J. Winkelman, a specialist in the field, highlighted this critical distinction. He noted that both disorders involve nearly nightly bingeing at multiple nocturnal awakenings, characterized by excessive calorie intake or a perceived loss of control over consumption. Both also share common occurrences, affecting approximately one to five percent of adults, predominantly women, with a young adult onset and a chronic course. They can lead to weight gain, sleep disruption, and feelings of shame. Familial bases and comorbid depression and daytime eating disorders are also observed in both conditions. However, the level of consciousness during the nighttime eating episodes remains the most prominent cited distinction, making it the chief factor doctors rely on for diagnosis. Misdiagnosis of NSRED for NES is a common error due to their similarities.
Behavioral Manifestations and Potential Dangers
Patients with NSRED exhibit a range of specific behaviors during their sleep-eating episodes. These often include partial arousals from sleep, typically within two to three hours of sleep onset, followed by rapid and "out of control" ingestion of food. The types of food consumed can be bizarre, including unusual amalgamations, raw, frozen, or spoiled items, and even potentially harmful substances like glue, wood, or other toxic materials. Examples cited include salt or sugar sandwiches, buttered cigarettes, and odd mixtures prepared in a blender.
During these episodes, individuals with NSRED may be messy or even injure themselves. They might eat with their bare hands or attempt to use utensils carelessly, leading to cuts, burns from scalding fluids or solids, or injuries from running into walls, kitchen counters, and furniture. Other notable symptoms include significant weight gain over short periods, especially in women, daytime irritability due to poor sleep, and vivid dreams. The behavioral sequence is often characterized by a rapid, "automatic" arising from bed and immediate entry into the kitchen, distinguishing it from regular sleepwalking. These symptoms are consistent across weekdays, weekends, and vacations, with eating excursions erratically spread throughout the sleep cycle. Early recognition of these symptoms by trained physicians is crucial to prevent self-injury and initiate appropriate treatment.
