Searching food during the night: the role of video-polysomnography in the characterization of the night eating syndrome.

OBJECTIVES: To describe the video-polysomnographic (VPSG) features of the night eating syndrome (NES), exploring the existence of potential subtypes. METHODS: In this study, 20 consecutive patients with NES according to the most recent diagnostic criteria underwent an overnight VPSG. None of them presented with a sleep-related eating disorder (SRED). VPSG recordings were reviewed identifying all eating episodes. For each episode, eating latency (time delay from awakening to food intake), eating duration (time between eating onset to eating offset) and sleep latency after eating offset (time delay from eating offset to sleep) were calculated. Total episode duration was considered as the time between awakening and sleep latency after eating offset. RESULTS: Ten patients fulfilled the A1 core criterion for NES (evening hyperphagia with consumption of at least 25% of the daily caloric intake after the evening meal); within this group, eight patients also fulfilled the A2 criterion (at least two episodes of nocturnal eating per week) and were thus included in the evening hyperphagia (EH) subgroup. The remaining 10 patients satisfied only the A2 core criterion for NES, constituting the nocturnal ingestion (NI) subgroup. We recorded 20 eating episodes, seven in the EH group and 13 in the NI group. In the EH subgroup, three eating episodes occurred before sleep onset, one after an awakening from non-rapid eye movement (NREM) stage 1 sleep, two from NREM stage 2 and one from REM sleep. All 13 NI episodes occurred after an awakening from sleep (1 from NREM stage 1 sleep, 8 from NREM stage 2 and four from NREM stage 3). In EH patients, eating latency, total episode duration and sleep latency after eating offset were significantly longer than in NI patients. CONCLUSION: Our VPSG data from a case series of 20 patients referred to our center for nocturnal eating indicate potential different NES subtypes. This distinction may have an impact on patients' treatment and follow-up.

Psychometric properties and gender invariance of the simplified Chinese version of Night Eating Questionnaire in a large sample of mainland Chinese college students.

PURPOSE: The Night Eating Questionnaire (NEQ) is the most frequently used instrument for assessing night eating syndrome (NES), and it has been translated to many languages, including a traditional Chinese version in Taiwan. However, significant differences exist in the social, linguistic, and cultural contexts between mainland China and Taiwan. For its use in mainland China, a simplified Chinese version is needed and its psychometric properties should be further evaluated. Thus, the current study aimed to obtain a simplified Chinese NEQ (SC-NEQ) and validate its psychometric properties. METHODS: According to standard procedures, the SC-NEQ was obtained by language transformation from the traditional Chinese version of NEQ. The SC-NEQ was then administered to 1273 mainland Chinese college students recruited from three provinces in mainland China. RESULTS: The four-factor structure of the original English NEQ (morning anorexia, evening hyperphagia, mood/sleep, and nocturnal ingestions) was confirmed in the current sample. Moreover, a second-order model also fitted the data well. The SC-NEQ showed good reliability with a Cronbach's alpha and omega of 0.70 and 0.83, respectively. The total score of the SC-NEQ was significantly and moderately correlated with eating pathology (r = .35, p < .01). Strong measurement invariance across gender groups was also supported. CONCLUSIONS: These findings suggest that the SC-NEQ can be a useful tool to assess NES in mainland China. LEVEL OF EVIDENCE: V, descriptive (cross-sectional) study.

The relationship between night eating symptoms and disordered eating attitudes via insomnia and chronotype differences.

Humans' sleep timing and the psychological construct "diurnal preference" determines their "chronotype" (i.e., morning or evening type). Diurnal preferences can affect sleep-awake rhythms and eating behaviors. Our aim in this study was to examine the relationship between night eating symptoms and disordered eating attitudes by evaluating insomnia and chronotype differences in university students. The participants, 383 university students, filled out a package of psychological tools, including the Morningness-Eveningness Questionnaire, the Insomnia Severity Index, the Night Eating Questionnaire, and the Eating Attitude Test. One way analysis of variance was used to investigate the relationship of chronotypes with scale scores, and mediation regression analysis was used to investigate the indirect effects of night eating symptoms on disordered eating attitudes. Insomnia and night eating scores of the participants varied statistically according to chronotypes, and both insomnia and night eating scores were associated with the evening type. Findings show that night eating symptoms have a direct effect on the chronotype differences and insomnia and an indirect effect on disordered eating attitudes, by increasing insomnia scores. In conclusion, night eating syndrome may represent the misalignment of food intake and may shift the circadian rhythm to delayed sleep phase, acting as a peripheral oscillator in human.

Validation of the Night Eating Diagnostic Questionnaire (NEDQ) and its relationship with depression, sleep quality, "food addiction", and body mass index.

Night eating syndrome (NES) is commonly assessed using the Night Eating Questionnaire (NEQ), a validated scale of symptom severity, which does not assess all diagnostic criteria. The Night Eating Diagnostic Questionnaire (NEDQ) assesses all diagnostic criteria, but has not been fully validated. The study purpose was to establish convergent validity for the NEDQ with the NEQ. It was also expected that higher NEDQ scores would be associated with elevated depression, poorer sleep quality, "food addiction," and BMI as in other studies of NES. Students (n = 254) and community members (n = 468) were administered the NEQ, NEDQ, Pittsburgh Sleep Quality Index, Zung Self-report Depression Scale (SDS), and the Yale Food Addiction Scale (YFAS). Convergent validity between the NEDQ and the NEQ was demonstrated; the scores were significantly positively correlated. There was good agreement between the NEDQ and the NEQ in diagnosis of NES; 56% of those diagnosed by the NEDQ met the threshold score on the NEQ, while the other 44% did not. Only 5 participants out of 33 who met the NEQ threshold score for NES did not meet the NEDQ diagnostic criteria. MANOVA revealed that higher NEDQ was associated with higher SDS and YFAS scores and poorer sleep quality. Full-syndrome NES by the NEDQ was associated with higher BMI in the community group unlike the student group. Scores on all the other questionnaires were higher in the community group. The discrepancies between NEDQ and NEQ diagnosis may be due to differences in construction of the questionnaires and specifically due to the NEDQ being designed for diagnosis. The NEQ provides a convenient global score for NES severity, whereas the NEDQ, which shows convergent validity with the NEQ, provides clinically useful diagnostic categories.