When someone repeatedly gets up during the night and eats uncontrollably, often in an unconscious state, it doesn’t take long before the underlying cause is sought. Sleep eating can become a serious problem, and the particular triggers may not be completely obvious. Consider some of the causes of sleep eating and what can be done about it.
The Classification of Sleep Eating
Sleep eating is one of the conditions known as a parasomnia. These abnormal behaviors during sleep include common actions like sleepwalking, sleep talking, and even night terrors. In general, the parasomnias can be broken down into two broad groups: those associated with rapid eye movement (REM) sleep and those associated with non-REM sleep. Dream enactment during REM sleep is also known as REM behavior disorder, and it typically affects men over the age of 50. The remaining parasomnias fall into the other category.
There are two diagnoses used to describe eating at night or out of sleep. Night eating syndrome involves compulsive eating late at night, but the person remains fully awake. Night eating syndrome is caused by dysfunction of the hypothalamic-pituitary axis. In contrast, sleep-related eating disorder (SRED) usually occurs immediately following a period of sleep. The affected person may have partial or complete unconsciousness with limited recall. The episodes typically include eating a large amount of somewhat unusual foods. What would cause such an event to occur?
Potential Causes of Sleep Eating
Sleep eating is often associated with another sleep disorder. Most commonly, people with sleep eating also experience sleepwalking (also known as somnambulism). When a sleepwalker begins to eat at night, the eating becomes the more predominant occurrence in sleep. Other conditions that disrupt the integrity of sleep, making fragmentation more common, can also lead to sleep eating. These sleep conditions include restless legs syndrome (RLS), periodic limb movement disorder, obstructive sleep apnea, and an irregular circadian rhythm.
The use of medications, especially certain sleeping pills, can also be a major cause of sleep eating. In particular, Ambien (sold as the generic zolpidem) and Halcion (or triazolam) have been implicated. Other medications that can affect the brain may also play a role, including medications like lithium, Benadryl (or diphenhydramine), and Wellbutrin (or bupropion).
Sleep eating may occur more often in the setting of stress, especially after a major life event like a divorce or death. It may also appear in the context of smoking, alcohol, or illicit substance cessation. It may manifest after daytime dieting as well, and may be associated with eating disorders such as anorexia and bulimia.
There are a few other rare causes of sleep eating. It may occur with onset of narcolepsy, which also causes excessive daytime sleepiness and cataplexy. It may be part of autoimmune hepatitis or even encephalitis. It may be part of a dissociative state, in which a person becomes detached from his or her actions. Sleep eating does not typically occur as a seizure, but it could theoretically occur in the confusional post-ictal state that may follow one.
For some people, the cause of sleep eating remains obscure and the condition is said to be idiopathic.
What Pathology Underlies Sleep Eating?
Many people wonder what the underlying problem with the body is that leads to sleep eating. It may represent the final outcome of multiple potential pathways. Sleep eating represents a mixture of states of consciousness, with wakefulness and sleep occurring simultaneously. The part of the brain that controls movement may be functioning while the part that controls memory or consciousness remains turned off. The unifying mechanism remains unknown, however.
It is key to recognize, however, that 80% of people with sleep eating who undergo a sleep study have another sleep disorder that contributes to their episodes. Therefore, it is very important to undergo a sleep study to identify this as a potential cause. This will allow the appropriate selection of treatment to end the sleep eating episodes.
"The International Classification of Sleep Disorders: Diagnostic & Coding Manual." American Academy of Sleep Medicine, 2nd Edition. 2005.
Kryger, MH et al. "Principles and Practice of Sleep Medicine." Elsevier, 5th edition. 2011.