Recent demonstration of an effective treatment for night eating syndrome (1) argues for wider recognition of the disorder to benefit the many persons who suffer from it. These include 1.1%—1.5% of the general population, 6%—16% of patients in weight reduction programs, and 8%—42% of candidates for bariatric surgery. Viewed as a delay in the circadian rhythm of food intake, night eating syndrome is defined by two core criteria: evening hyperphagia (ingestion of at least 25% of daily calories after supper) and/or awakenings with ingestions at least three times a week. These criteria have identified persons whose behavior manifests a coherent biobehavioral model of night eating syndrome, supporting its construct validity. Single photon emission computed tomography has shown significant elevation of serotonin transporters in the midbrain of night eaters (2). This elevation may result from a genetic vulnerability transmitted as part of the established heritability of night eating syndrome (3), which is triggered by the stress that night eaters report. Elevations in serotonin transporter levels lead to decreased postsynaptic serotonin transmission and should impair circadian rhythms and satiety. These deficits suggest that improvement in serotonin function should alleviate night eating syndrome, and the selective serotonin reuptake inhibitors do precisely that. Reports of response to paroxetine and fluvoxamine have been accompanied by two larger open-label trials with a strong response to sertraline. Finally, a placebo-controlled, double-blind study of sertraline showed significant improvements in both of the criteria for night eating syndrome (1).

Night eating may be a pathway to obesity; it preceded the onset of obesity in three studies and predicted major weight gain among female night eaters who were already obese (4). Five animal models, each of a different etiology, have also shown a circadian dysrhythmia with hyperphagia and obesity. In addition to its contribution to weight gain, night eating syndrome is a source of distress, making it worthy of treatment for its own sake.