Restless Eating, Restless Legs, and Sleep Related Eating Disorder

Curr Obes Rep (2014) 3:108–113 DOI 10.1007/s13679-013-0083-6 PSYCHOLOGICAL ISSUES (M HETHERINGTON AND V DRAPEAU, SECTION EDITORS) Restless Eating, Restless Legs, and Sleep Related Eating Disorder Michael J. Howell Published online: 19 December 2013 # Springer Science+Business Media New York 2013 Abstract Restless legs syndrome (RLS) often presents with a primary complaint of sleep initiation difficulty with only ambiguous allusions to motor symptoms. This may result in the condition being misdiagnosed as a psychophysiological insomnia. Further, nocturnal eating is common in RLS and like the classic motor symptoms, patients will describe an inability to initiate sleep until their urge (to eat) is addressed. Restless nocturnal eating arises, intensifies, and subsides in parallel to motor symptoms. Once misdiagnosed as psychophysiological insomnia, RLS patients are frequently treated with benzodiazepine receptor agonists. The CNS actions of these sedating agents, suppression of memory and executive function, unleash predisposed amnestic behaviors. In the case of RLS this would be expected to include the inappropriate ambulatory and eating behaviors of sleep related eating disorder (SRED). The evidence and implications of a link between the restless eating of RLS and SRED is presented here. Keywords Restless legs syndrome . Nocturnal eating . Restless eating . Sleep related eating disorder . Night eating syndrome . Willis-Ekbom syndrome Introduction Restless legs syndrome (RLS) is a vexing disorder for patients and clinicians. It is traditionally defined as a discomfort, predominantly in the evening and localized to the lower extremities, which compels the afflicted to move. Movement relieves the symptoms although only momentarily. For M. J. Howell (*) Department of Neurology, University of Minnesota, 717 Delaware Street SE, Room 516, Minneapolis, MN 55414, USA e-mail: patients, RLS can be notoriously difficult to describe, as language may fail to characterize the dysesthesia. Symptoms are reported in a seemingly infinite number of ways including: restless, tingling, cramping, painful, numbing, burning, aching, creepy-crawly, itching, and so on. Often patients are fully unable to localize or describe the sensations at all, but instead state that there is something wrong causing an urge to move. Clinical investigators have long reported that RLS patients have other, non-motor compulsions. Most notably the majority of patients with RLS will describe an urge to eat that coincides with evening motor symptoms [1••, 2, 3•]. This urge prevents the individual from falling asleep until food is ingested, at which point the feeling abates and sleep may be initiated [2, 4–6•]. Karl Ekbom, in his seminal 1960 publication describing RLS wrote the following. “They often have to get up and walk, “like a caged bear,” to quote one of my patients, or they go into the kitchen and get something to eat…” [1••]. Further, this nocturnal eating is not merely “killing time” because patients with other forms of insomnia are more likely to have awakenings than patients with RLS but less likely to eat [3•]. The International Restless Legs Syndrome Study Group has suggested that the name itself be changed from RLS to Willis-Ekbom’s syndrome in part to recognize its non-motor manifestations [7]. In this report, for the sake of simplicity the disorder will be referred to as RLS. The cryptic nature of this common disorder (approximately 10 % of the population) often results in misdiagnosis and mistreatment leading to complicated amnestic behaviors [5]. Frequently, the only complaint a patient with RLS will give a clinician is that they “can’t fall asleep”. The sleep initiation difficulties are then easily misattributed to a cognitive hypervigilant insomnia such as psychophysiological insomnia. Medications for pathophysiological insomnia, such as the ubiquitously prescribed benzodiazepine receptor agonists, suppress memory and executive function. Thus, it may be Curr Obes Rep (2014) 3:108–113 expected that when RLS patients are prescribed hypnotic agents, complicated amnestic behaviors such as walking and eating emerge. The objectives of this clinical review are: to demonstrate that restless eating is a common manifestation of RLS, that RLS is commonly mistaken for psychophysiological insomnia, and that mistreatment of RLS with sedative hypnotic medication would be expected to result in the amnestic binge eating of sleep related eating disorder. Sleep Related Eating Disorder (SRED) In 1991, SRED was first described and essentially characterized as sleepwalking with eating. It is defined as a parasomnia (abnormal behavior at night) with recurrent episodes of eating after an arousal from sleep occurring in an unconscious, out of control manner. Similar to sleepwalking, patients could not be easily awakened or redirected [8••]. Adverse consequences have included: weight gain, inedible food consumption, dangerous food preparation, dental caries, and hyperglycemia in diabetic patients [5, 8••, 9]. Also similar to sleepwalking, numerous cases in both the original and subsequent reports noted a strong association with sedative medications. Most notably, a rise in SRED cases has paralleled the utilization of benzodiazepine receptor agonists (BRA) [5, 8••–11]. SRED is a common condition. A self-administered questionnaire determined a prevalence rate of 5 % among a group of college students [12]. This finding was similar to a survey of 1235 general psychiatry patient’s which noted a 4 % lifetime prevalence of SRED [13]. In patients with daytime eating disorders, the prevalence is even higher at 17 % among inpatients and 9 % among out-patients [12]. SRED patients described a long history of nocturnal eating (mean duration >10 years) and nearly all report eating on a nightly basis [9]. A substantial proportion (23 %) describes eating greater than five times a night [14]. The majorities (6083 %) of reported cases are female and nocturnal foods are higher in carbohydrates and fats then daytime ingestions [8••, 9, 14]. This condition is associated with weight gain and obesity; however, a causality has not been established. In the original 1991 case series nearly half of all patients fulfilled established criteria for being overweight [8••] and in a follow up report 44 % of patients claimed that greater than 20 % of their excess weight was related to nocturnal eating [4]. Amnestic food preparation can be dangerous. SRED patients have reported injuries such as drinking excessively hot liquids, choking, and lacerations. Furthermore, inedible and noxious compounds have been consumed such as: egg shells, coffee grounds, sunflower shells, cigarettes, glue, and cleaning solutions. Finally, patients with food allergies have ingested substances that during the daytime they take extreme precautions to avoid [4, 9, 15]. 109 SRED and Sedating Medications Reports have noted that patients with SRED are often primed by se (...truncated)