The contribution of sleep to anorexia nervosa severity

Associations between intraindividual variability in weekday-weekend sleep timing and duration and eating disorder pathology

Sleep disruptions may be risk factors for eating disorder symptoms. However, mean estimates of sleep characteristics may not be ideal metrics, considering many individuals have irregular sleep patterns. Although variability in sleep-wake timing is associated with irregular eating patterns among individuals with eating disorders (Linnaranta et al., 2020), studies of sleep intraindividual variability (IIV) and eating pathology are limited. To fill this gap, we evaluated two indices of sleep IIV from weekdays-to-weekends and their relation to eating disorder risk. The sample was drawn from the 2018-2019 Healthy Minds Study (N = 25,879). We conducted two binary logistic regressions predicting screening positive for an eating disorder from IIV indices, adjusting for depression and mean sleep time. Greater IIVtiming (i.e., greater shifts in the timing of the sleep midpoint between weekdays and weekends) was associated with greater odds of screening positive for an eating disorder (OR = 1.049). Greater IIVduration (i.e., greater shifts in duration of sleep between weekdays and weekends) was associated with lesser odds (OR = 0.967); however, suppressor effects of depression likely explain this finding. Greater mean duration of sleep was associated with lower odds of screening positive for an eating disorder in both models. Results are consistent with theories emphasizing the importance of sleep IIV in conceptualizing psychopathology risk; however, effect sizes were small and may have limited clinical significance. By only asking about mean sleep duration, clinicians may miss other sleep-related predictors of eating disorder psychopathology. Findings support investigating techniques to regularize sleep patterns among people with disordered eating.

The brainstem reticular formation pivots abnormal neural transmission in the course of Anorexia Nervosa

Anorexia nervosa (AN) represents an eating disorder, which features the highest rate of mortality among all psychiatric disorders. The disease prevalence is increasing steadily, and an effective cure is missing. The neurobiology of the disease is largely unknown, and only a few studies were designed to disclose specific brain areas, where altered neural transmission may occur. In AN behavioral alterations surpassing altered feeding are present, which often involve archaic behaviors finalized to the survival of the species. In fact, alterations of sleep and reward-driven behavior accompany the eating disorder, where a disruption of peripheral and central circadian rhythms occurs along with effortful behaviors, aberrant learning and mild cognitive impairment. Abnormal behavior often co-exists with a number of metabolic alterations in peripheral organs. The present article wishes to analyze the potential role of altered brain circuitry within the brainstem reticular formation during AN. In fact, this brain area contains neuronal nuclei and pathways, which are pivotal in connecting eating pattern with archaic behaviorsand autonomic activity within peripheral organs. A number of reticular nuclei releasing catecholamine and non-catecholamine neurotransmittersare evidenced in relationship with altered behavioral states and vegetative control to produce this psycho-metabolic disorder. The relevance of the reticular formation in sustaining the disorder is discussed in the light of developing effective therapeutic strategies.

An evolutionary perspective on the genetics of anorexia nervosa

Anorexia nervosa (AN) typically emerges around adolescence and predominantly affects females. Recent progress has been made in identifying biological correlates of AN, but more research is needed to pinpoint the specific mechanisms that lead to its development and maintenance. There is a known phenotypic link between AN, growth and sexual maturation, yet the genetic overlap between these phenotypes remains enigmatic. One may hypothesize that shared factors between AN, energy metabolism and reproductive functions may have been under recent evolutionary selection. Here, we characterize the genetic overlap between AN, BMI and age at menarche, and aimed to reveal recent evolutionary factors that may help explain the origin of AN. We obtained publicly available GWAS summary statistics of AN, BMI and age at menarche and studied the polygenic overlap between them. Next, we used Neandertal Selective Sweep scores to explore recent evolutionary selection. We found 22 loci overlapping between AN and BMI, and 9 loci between AN and age at menarche, with 7 of these not previously associated with AN. We found that loci associated with AN may have been under particular evolutionary dynamic. Chronobiology appeared relevant to the studied genetic overlaps and prone to recent evolutionary selection, offering a promising avenue for future research. Taken together, our findings contribute to the understanding of the genetic underpinning of AN. Ultimately, better knowledge of the biological origins of AN may help to target specific biological processes and facilitate early intervention in individuals who are most at risk.

Disordered eating behaviours during the menopausal transition: a systematic review

Disordered eating refers to a range of eating behaviours and attitudes towards weight and food that can negatively influence physical and psychosocial well-being. The menopausal transition could be a vulnerable period for disordered eating due to major hormonal fluctuations, menopausal symptoms, common body composition shifts, and an increased risk of psychological challenges. This systematic review aimed to summarize evidence on the associations between the menopausal transition and disordered eating. Records published before October 2023 were identified through MEDLINE, PsycINFO, Scopus, Embase, and CINAHL. Studies investigating associations between menopausal status, menopausal symptoms, or reproductive hormone levels, and disordered eating during the menopausal transition were sought. A total of 1301 non-duplicate records were screened, with 10 studies deemed eligible for inclusion. Most included studies used a cross-sectional design (n = 9). Findings include potentially higher levels of binge eating during the perimenopausal stage, whereas restrictive eating behaviours appeared more common during postmenopause compared to premenopause. Both studies investigating menopausal symptoms found strong positive associations with disordered eating. Nonetheless, findings are equivocal with contrasting results and limited methodological quality across studies. Further research is needed to verify these findings and better assist health professionals in supporting healthy eating behaviours in menopausal women during this complex transition. (PROSPERO ID: CRD42021290736).

Preliminary study: cognitive behavioural therapy for insomnia in adolescents with anorexia nervosa

PURPOSE

Insomnia and anorexia nervosa (AN) are frequently comorbid, negatively affecting the evolution and the prognosis of AN. Within this framework, the management of sleep disorders appears as critical. The aim of this retrospective study is to assess, for the first time, the efficacy of cognitive and behavioural therapy for insomnia (CBT-I) on sleep disturbances in adolescents with AN. To do so, we investigated the impact of CBT-I on sleep disturbances and sleep-related outcomes, in BMI, AN symptoms, anxiety and depressive symptoms, emotionality and quality of life. These features were compared between two groups of patients with AN, one following CBT-I, and the other receiving the regular treatment at the psychiatric unit.

METHODS

Data collection occurred between January and May 2022. The study included 42 adolescents in-treatment at the Eating Disorders care specialised unit at Salvator Hospital in Marseille. They were randomly assigned to the CBT-I group (N = 31) or the control group (N = 11). Several clinical elements were assessed using sleep diaries and self-report questionnaires.

RESULTS

Participants undergoing CBT-I showed a significant improvement in sleep latency, total wake time and sleep efficacy, as well as in physical well-being. No significant effects were found regarding AN symptoms.

CONCLUSION

These preliminary findings provide support for CBT-I effectiveness in adolescents with AN, as shown by significant improvements in several sleep parameters, as well as in physical well-being. These promising results, underline the relevance of this topic and its potential benefits for a more appropriate treatment for adolescents with AN.

LEVEL OF EVIDENCE

Level V, retrospective study.

Similarities and differences regarding acute anorexia nervosa and semi-starvation: does behavioral thermoregulation play a central role?

Objective

To clarify the association between acute anorexia nervosa (AN) and semi-starvation (SS) by focusing on similarities and differences in physiology, mood, and behavior.

Method

A comparison of published literature between these two groups.

Results

Both groups show similar hormonal and metabolic changes in response to caloric restriction and extreme weight loss (~25%). Associated changes result in a reduced body temperature (Tcore-low). Maintenance of body temperature within a specific range is crucial to survival. However, both groups cannot activate autonomic strategies to maintain their Tcore-low, such as increasing metabolic rate, constricting skin blood vessels, or shivering. Furthermore, Tcore-low increases the individuals' "coldness sensations" throughout the body, hence the frequent reports from ANs and SSs of "feeling cold." To eliminate these uncomfortable "coldness sensations" and, importantly, to maintain Tcore-low, ANs, and SSs "select" different thermoregulatory behavioral strategies. It is proposed that the primary differences between AN and SS, based on genetics, now manifest due to the "selection" of different thermo-regulatory behaviors. AN patients (ANs) "select" hyperactive behavior (HyAc), which increases internal metabolic heat and thus assists with maintaining Tcore-low; in harmony with hyperactive behavior is a lively mood. Also related to this elevated arousal pattern, ANs experience disrupted sleep. In contrast, SS individuals "select" a passive thermo-behavioral strategy, "shallow torpor," which includes reduced activity, resulting in energy conservation. In addition, this inactivity aids in the retention of generated metabolic heat. Corresponding to this lethargic behavior, SS individuals display a listless mood and increased sleep.

Conclusion

Initial similarities between the two are attributable to physiological changes related to extreme weight loss. Differences are most likely attributable to genetically programmed "selection" of alternate thermoregulatory strategies, primarily to maintain Tcore-low. However, if acute AN is prolonged and evolves into a chronic condition, AN will more closely align with starvation and more precisely reflect SS symptomology.

Sleep Pathologies and Eating Disorders: A Crossroad for Neurology, Psychiatry and Nutrition

The intricate connection between eating behaviors and sleep habits is often overlooked in clinical practice, despite their profound interdependence. Sleep plays a key role in modulating psychological, hormonal and metabolic balance and exerting an influence on food choices. Conversely, various eating disorders may affect sleep continuity, sometimes promoting the development of sleep pathologies. Neurologists, nutritionists and psychiatrists tend to focus on these issues separately, resulting in a failure to recognize the full extent of the clinical conditions. This detrimental separation can lead to underestimation, misdiagnosis and inappropriate therapeutic interventions. In this review, we aim to provide a comprehensive understanding of the tangled relationship between sleep, sleep pathologies and eating disorders, by incorporating the perspective of sleep experts, psychologists and psychiatrists. Our goal is to identify a practical crossroad integrating the expertise of all the involved specialists.

Exploring the Relationship between Disordered Sleep and Mood in Male Anorexia Nervosa: An Actigraphy Study

Eating disorders (EDs), including anorexia nervosa (AN), are severe psychological disorders that affect individuals' eating behaviours and body perception. Previous research has shown that people with EDs often report poorer sleep. Some literature has suggested that it is mood dysregulation that mediates the link between EDs and sleep. However, the majority of previous studies only focused on females, while male ED patients have been overlooked. Therefore, the present study aimed to investigate the relationships between EDs, mood, and sleep among male ED patients. Using a mixture of actigraphy recordings and self-reported questionnaires, the current study analysed a total 33 adult male participants diagnosed with AN. The participants first wore an actigraphy device for seven continuous days, following which their ED severity and mood were assessed by the Eating Disorder Examination Questionnaire (EDE-Q) and Depression Anxiety Stress Scale (DASS), respectively. The descriptive actigraphy results suggested that, similar to females, males with AN also showed disturbed sleep, including insomnia, sleep fragmentation, low sleep efficiency, and increased napping sessions. However, when ED severity was correlated against actigraphy data and mood, no significant relationships were found between them. Thus, it was suggested that future studies may investigate discrete ED symptoms instead of global ED severity interacting with sleep and mood. Overall, this study represents an initial step in the investigation of EDs and sleep and mood dysregulation among an under-represented sample.

The Role of Leptin in Rodent and Human Sleep: A Transdiagnostic Approach with a Particular Focus on Anorexia Nervosa

This narrative review addressed to both clinicians and researchers aims to assess the role of hypoleptinemia in disordered sleep with a particular focus on patients with anorexia nervosa (AN). After introducing circadian rhythms and the regulation of circulating leptin, we summarize the literature on disordered sleep in patients with AN and in fasting subjects in general. We highlight novel single-case reports of substantially improved sleep within days after initiation of off-label metreleptin treatment. These beneficial effects are set in relationship to current knowledge of disordered sleep in animal models of an impaired leptin signaling. Specifically, both absolute and relative hypoleptinemia play a major role in animal models for insomnia, obstructive sleep apnea and obesity hypoventilation syndrome. We pinpoint future research required to complement our understanding of the role of leptin in sleep in patients with acute AN. Moreover, within the section clinical applications we speculate that human recombinant leptin may be useful for the treatment of treatment-resistant sleep-wake disorders, which are associated with (relative) hypoleptinemia. Overall, we stress the role of the hormone leptin in sleep.

Engagement of the brain orexin system in activity-based anorexia behaviour in mice

While excessive physical activity is common amongst anorexia nervosa (AN) patients, contributing to their low body weight, little is known about the underlying biology and effective treatments targeting the hyperactivity are lacking. Given the role of orexin in arousal, physical activity and energy expenditure, we sought to investigate i) the extent to which orexin neurons are activated during severe anorectic state in the activity-based anorexia (ABA) mouse model, and ii) if the dual orexin receptor antagonist suvorexant can reduce physical activity during ABA. The Fos-TRAP2 technique enable us to visually capture active neurons (Fos expressing) during severe anorectic state in the ABA mouse model, and by immunohistochemistry, determine the extent to which these active neurons are orexin positive. In addition, suvorexant was administered peripherally to ABA mice and running activity was monitored. We found that a large population of orexin neurons in the hypothalamus are activated by ABA and that peripheral administration of suvorexant decreases food anticipatory activity in these mice. We conclude that orexin may be a suitable target to treat hyperactivity in AN and recommend further studies to examine the efficacy of suvorexant in aiding AN patients to control their drive for hyperactivity.

Sensor technology in eating disorders research: A systematic review

OBJECTIVE

Sensor technologies offer exciting potential to objectively measure psychopathological correlates of eating pathology and eating disorder (ED) research utilizing sensors has rapidly proliferated in the past several years. The aims of the present review are: (1) characterize the types of sensors that have been utilized in ED research, (2) identify the psychopathological factors relevant to EDs that have been assessed using sensors, (3) describe the data supporting the validity and reliability of these sensors, (4) discuss limitations associated with these sensors, and (5) identify gaps that persist within the ED literature with regard to use of sensor technologies.

METHOD

A systematic search was conducted of PubMed, PsycINFO, Web of Science, ProQuest, and "gray" literature sources. Eligible publications were empirical studies that utilized sensors to measure at least one psychological variable among clinical ED populations.

RESULTS

Sensors have been utilized with ED samples to measure eating behaviors, physical activity, sleep, autonomic nervous system activity, eyeblink startle response, visual attention, and visual-haptic object integration. The reliability and validity of these sensors varies widely and there are a number of significant gaps that remain in the literature with regard to the types of sensors utilized, context in which sensors have been used, and populations studied.

DISCUSSION

The existing literature utilizing sensors within ED research largely support the feasibility and acceptability of these tools. Sensors should continue to be utilized within the field, with a specific focus on examining the reliability and validity of these tools within ED samples and increasing the diversity of samples studied.

PUBLIC SIGNIFICANCE STATEMENT

Sensor technologies, such as those included in modern smartwatches, offer new opportunities to measure factors that may maintain or contribute to symptoms of eating disorders. This article describes the types of sensors that have been used in eating disorders research, challenges that may arise in using these sensors, and discusses new applications of these sensors that may be pursued in future research.