Behavioral and neuroendocrine characteristics of the night-eating syndrome

Context Investigators first described the night-eating syndrome (NES), whic h consists of morning anorexia, evening hyperphagia, and insomnia, in 1955, but, to our knowledge, this syndrome has never been subjected to careful c linical study. Objective To characterize NES on the basis of behavioral characteristics an d neuroendocrine data. Design and Setting A behavioral observational study was conducted between J anuary 1996 and June 1997 in a weight and eating disorders program at the U niversity of Pennsylvania. A neuroendocrine study was conducted from May th rough August 1997 at the Clinical Research Center of the University Hospita l, Tromso, Norway, Subjects The behavioral study included 10 obese subjects who met criteria f or NES and 10 matched control subjects. The neuroendocrine study included 1 2 night eaters and 21 control subjects. Behavioral study subjects were obse rved for 1 week on an outpatient basis, and neuroendocrine study subjects w ere observed during a 24-hour period in the hospital. Main Outcome Measures The behavioral study measured timing of energy intake , mood level, and sleep disturbances. The neuroendocrine study measured cir cadian levels of plasma melatonin, leptin, and cortisol, Results In the behavioral study, compared with control subjects, night eate rs had more eating episodes in the 24 hours (mean [SD], 9.3 [0.6] vs 4.2 [0 .2]; P<.001) and consumed significantly more of their daily energy intake a t night than did control subjects (56% vs 15%; P<.001), They averaged 3.6 ( 0.9) awakenings per night compared with 0.3 (0.3) by controls (P<.001). In night eaters, 52% of these awakenings were associated with food intake, wit h a mean intake per ingestion of 1134 (1197) kJ, None of the controls ate d uring their awakenings. In the neuroendocrine study, compared with control subjects, night eaters had attenuation of the nocturnal rise in plasma mela tonin and leptin levels (P<.001 for both) and higher circadian levels of pl asma cortisol (P = .001). Conclusion A coherent pattern of behavioral and neuroendocrine characterist ics was found in subjects with NES.