Defining the borders between Sleep-Related Eating Disorder and Night Eating Syndrome

Objectives: Nocturnal eating is a common symptom of two clinical conditions with different pathogenesis and needing different therapeutic approaches: Sleep Related Eating Disorder (SRED) and Night Eating Syndrome (NES). The first is considered a parasomnia while the second is an eating disorder; however, the distinction between SRED and NES is still a controversial matter. The aim of this study was to better define psychological, behavioral, and polysomnographic characteristics of the two syndromes. Methods: An eating disorders' specialist tested a group of 28 nocturnal eaters diagnosed as affected by SRED by a sleep expert, following the current criteria of the international classification of sleep disorders, to find out if any of them was affected by NES according to the criteria suggested by both sleep and eating disorders specialists during the first international meeting on Night Eating Syndrome (Minneapolis, 2009) and if they had specific psychological or polysomnographic characteristics. Results: Twenty-two subjects were diagnosed to be affected by NES. They scored higher on the physical tension subscale of the Sleep Disturbance Questionnaire (SDQ) and on the mood and sleep subscale of the Night Eating Questionnaire (NEQ), but there were no other significant differences between SRED and NES patients nor for age, Body Mass Index (BMI), or gender distribution. Conclusions: The overlap between the symptomatology and the polysomnographic characteristics of the two pathologies and the difficulty in making a differential diagnosis between NES and SRED indicate the need for an update of the diagnostic criteria for SRED, as was recently done for NES.