Behavioral and neuroendocrine characteristics of the night-eating syndrome.
BACKGROUND
Investigators first described the night-eating syndrome (NES), which consists of morning anorexia, evening hyperphagia, and insomnia, in 1955, but, to our knowledge, this syndrome has never been subjected to careful clinical study.


OBJECTIVE
To characterize NES on the basis of behavioral characteristics and neuroendocrine data.


METHODS
A behavioral observational study was conducted between January 1996 and June 1997 in a weight and eating disorders program at the University of Pennsylvania. A neuroendocrine study was conducted from May through August 1997 at the Clinical Research Center of the University Hospital, Tromso, Norway.


METHODS
The behavioral study included 10 obese subjects who met criteria for NES and 10 matched control subjects. The neuroendocrine study included 12 night eaters and 21 control subjects. Behavioral study subjects were observed for 1 week on an outpatient basis, and neuroendocrine study subjects were observed during a 24-hour period in the hospital.


METHODS
The behavioral study measured timing of energy intake, mood level, and sleep disturbances. The neuroendocrine study measured circadian levels of plasma melatonin, leptin, and cortisol.


RESULTS
In the behavioral study, compared with control subjects, night eaters 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 at 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, with a mean intake per ingestion of 1134 (1197) kJ. None of the controls ate during their awakenings. In the neuroendocrine study, compared with control subjects, night eaters had attenuation of the nocturnal rise in plasma melatonin and leptin levels (P<.001 for both) and higher circadian levels of plasma cortisol (P = .001).


CONCLUSIONS
A coherent pattern of behavioral and neuroendocrine characteristics was found in subjects with NES.
Birketvedt
G S
GS
Laboratory of Gastroenterology, Institute of Clinical Medicine, University of Tromsö, Norway. gsb42nor@aol.com
Florholmen
J
J
Sundsfjord
J
J
Osterud
B
B
Dinges
D
D
Bilker
W
W
Stunkard
A
A
D000328:Adult; D000855:Anorexia / Q000503:physiopathology; D002940:Circadian Rhythm / Q000502:physiology; D005247:Feeding Behavior / Q000502:physiology; D001068:Feeding and Eating Disorders / Q000503:physiopathology*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D006963:Hyperphagia / Q000503:physiopathology; D020738:Leptin; D008297:Male; D008550:Melatonin / Q000097:blood; D009490:Neurosecretory Systems / Q000502:physiology*; D009765:Obesity; D016012:Poisson Distribution; D011506:Proteins / Q000378:metabolism; D012044:Regression Analysis; D007319:Sleep Initiation and Maintenance Disorders / Q000503:physiopathology; D018709:Statistics, Nonparametric; D013577:Syndrome
D020738:Leptin; D011506:Proteins; D008550:Melatonin; D006854:Hydrocortisone