The relationship between sleep, nutrition and mood: a study of patients with anorexia nervosa

Sleep disturbances in anorexia nervosa

INTRODUCTION

Sleep is crucial for physical and psychological health, and disturbances are closely linked to psychiatric disorders, making their management essential for improving treatment outcomes and preventing relapse. Although sleep disturbances are implicated in psychopathology of eating disorders, its role in anorexia nervosa (AN) remains unclear. This review aimed to characterise sleep in AN.

METHODS

A systematic search was conducted in four scientific databases, including papers from inception to 25 May 2024. A machine learning algorithm (ASReview) was utilised to screen titles and abstracts for eligibility. Sleep quantity, architecture, and quality were investigated. Meta-analyses were conducted to investigate the difference between patients with AN and healthy controls (HC) in total sleep time (TST), wake after sleep onset (WASO), sleep onset latency (SOL), sleep efficiency, Sleep Stage 1, 2, slow wave sleep, rapid eye movement (REM) sleep and REM latency. Certainty of evidence was assessed using the GRADE approach.

RESULTS

Out of 67 potentially eligible papers, 31 were included in this review, with 15 in the meta-analyses. Statistically significant average mean differences were found for TST (-32.1 min [95% CI: -50.9, -13.4]), WASO (19.0 min [95% CI: -2.4, 40.3]), and sleep efficiency (-4.4% [95% CI: -7.9, -0.9]). Additionally, Sleep stage 1 was significantly increased (2.4% [95%-CI: 0.05, 4.7]), while REM sleep was reduced (-2.1% [95%-CI: -4.2, -0.02]). Subgroup analysis showed that TST and WASO did not improve significantly after weight restoration.

CONCLUSION

Sleep in patients with AN is impaired, with lower TST and sleep efficiency, higher WASO, more time in stage 1 sleep, and less in REM. Weight restoration alone may not improve sleep. While more research is needed, substantial accompanying sleep disturbances in AN justifies addressing these in current treatment practice, also because of the chronic character of AN and importance of sleep for long term (mental) health.

Multi-organ transcriptome atlas of a mouse model of relative energy deficiency in sport

Insufficient energy intake to meet energy expenditure demands of physical activity can result in systemic neuroendocrine and metabolic abnormalities in activity-dependent anorexia and relative energy deficiency in sport (REDs). REDs affects >40% of athletes, yet the lack of underlying molecular changes has been a hurdle to have a better understanding of REDs and its treatment. To assess the molecular changes in response to energy deficiency, we implemented the "exercise-for-food" paradigm, in which food reward size is determined by wheel-running activity. By using this paradigm, we replicated several aspects of REDs in female and male mice with high physical activity and gradually reduced food intake, which results in weight loss, compromised bone health, organ-specific mass changes, and altered rest-activity patterns. By integrating transcriptomics of 19 different organs, we provide a comprehensive dataset that will guide future understanding of REDs and may provide important implications for metabolic health and (athletic) performance.

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.

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.

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.

Many faces of sleep regulation: beyond the time of day and prior wake time

The two-process model of sleep regulation posits two main processes regulating sleep: the circadian process controlled by the circadian clock and the homeostatic process that depends on the history of sleep and wakefulness. The model has provided a dominant conceptual framework for sleep research since its publication ~ 40 years ago. The time of day and prior wake time are the primary factors affecting the circadian and homeostatic processes, respectively. However, it is critical to consider other factors influencing sleep. Since sleep is incompatible with other behaviors, it is affected by the need for essential behaviors such as eating, foraging, mating, caring for offspring, and avoiding predators. Sleep is also affected by sensory inputs, sickness, increased need for memory consolidation after learning, and other factors. Here, we review multiple factors influencing sleep and discuss recent insights into the mechanisms balancing competing needs.

Differential effects of heat in the phases of the light-dark cycle in the activity-based anorexia model

BACKGROUND

This research builds on the studies on ambient temperature as a key influence in the recovery of rodents exposed to the activity-based anorexia (ABA) model. The ABA model is an experimental paradigm in which rodents under a restricted feeding schedule and with free access to an activity wheel show signs that parallel those of anorexia nervosa in humans.

OBJECTIVE

The present study focuses on the effects of applying heat during the different phases of the dark-light cycle in the activity levels, body weight, food intake, body temperature, and recovery rates of 30 male rats submitted to ABA.

METHOD

After reaching a 20% weight loss criterion, animals were randomly assigned to three experimental conditions: (a) continuous warming, (b) warming exclusively during the light phase, or (c) warming exclusively during the dark phase.

RESULTS

Differential effects were found depending on the modalities of warming: in comparison with either light or dark warming, continuous warming significatively decreased activity, facilitated weight gain, and maintained body temperature. Transient effects of warming were found both in the groups warmed either during light or dark periods exclusively.

DISCUSSION

The results suggest that both light and dark warming did not promote recovery in animals exposed to ABA. Evidence about the beneficial effects of continuous warming are in line with previous research and reinforces adding external heat as a useful tool in the treatment of anorexia nervosa.

Not the Function of Eating, but Spontaneous Activity and Energy Expenditure, Reflected in "Restlessness" and a "Drive for Activity" Appear to Be Dysregulated in Anorexia Nervosa: Treatment Implications

Anorexia nervosa (AN) is uncommon as a syndrome, despite widespread dieting or voluntary food restriction, especially among female adolescents. This suggests that restriction of caloric intake might not be the only component driving weight loss in AN. Historical observations and experimental evidence from energy expenditure studies and recordings from movement sensors reviewed in this paper reveal that AN is associated with motor activity levels and with an energy output not significantly different from that in normal-weight healthy age-matched controls. By contrast, other conditions of prolonged caloric under-nutrition are typically associated with loss of energy, slowing of movements and a decrease in self-initiated activity and well-being. Several hypotheses can be inferred from the findings: (a) that long term severe caloric restriction fails in downregulating movements and energy expenditure in AN. (b) Clinically and subjectively observable as mental and physical restlessness and continued motor activity, this restless energy, differing in intensity, seems to serve as the permissive factor for and possibly to drive exercise and hyperactivity in AN. (c) Such restless energy and increased arousal, generated sometime in the course of the weight loss process, appear to enhance the person's self-perception and wellbeing, to heighten proprioception, to intensify body awareness and to improve self-esteem. (d) Restlessness and continued motor activity may constitute a phenotype of AN. The therapeutic value of the concept of an abnormality in the energy regulatory system, likely the result of a host of genetic and epigenetic changes in AN, lies primarily in its heuristic and explanatory power and its potential for disease prevention. Restless energy as a permissive and important component for the development and in the maintenance of AN, does not fundamentally alter treatment, since prolonged food deprivation is the principal causal factor for the development of AN. Re-nutrition within a structured treatment plan, to include individual and family therapy and, if indicated, heat application, remains the most effective symptomatic treatment for AN. Corroboration of the concept of restless activation will require the patient's cooperation and input to identify and capture more precisely the experiences, sensations, and changes that allow the emaciated patient to remain mobile and active.

Sleep, eating disorder symptoms, and daytime functioning

OBJECTIVE

To investigate the relationship between eating disorders, body mass index (BMI), sleep disorders, and daytime functioning.

DESIGN

Survey.

SETTING

The Netherlands.

PARTICIPANTS

N=574 Dutch young adults (18-35 years old).

MEASUREMENTS

Participants completed a survey on eating and sleep habits including the Eating Disorder Screen for Primary care (ESP) and SLEEP-50 questionnaire subscales for sleep apnea, insomnia, circadian rhythm disorder (CRD), and daytime functioning. SLEEP-50 outcomes of participants who screened negative (≤2) and positive (>2) on the ESP were compared. In addition, SLEEP-50 scores of groups of participants with different ESP scores (0-4) and different BMI groups (ie, underweight, healthy weight, overweight, and obese) were compared using nonparametric statistics.

RESULTS

Almost 12% (n=67) of participants screened positive for having an eating disorder. Relative to participants without eating disorders, participants who screened positive for eating disorders reported significantly higher scores on sleep apnea (3.7 versus 2.9, P=0.012), insomnia (7.7 versus 5.5, P<0.0001), CRD (2.9 versus 2.3, P=0.011), and impairment of daytime functioning (8.8 versus 5.8, P=0.0001). ESP scores were associated with insomnia (r=0.117, P=0.005), sleep apnea (r=0.118, P=0.004), sleep quality (r=-0.104, P=0.012), and daytime functioning (r=0.225, P<0.0001), but not with CRD (r=0.066, P=0.112). BMI correlated significantly with ESP scores (r=0.172, P<0.0001) and scores on sleep apnea (r=0.171, P<0.0001). When controlling for BMI, the partial correlation between ESP and sleep apnea remained significant (r=0.10, P=0.015).

CONCLUSION

Participants who score positive for eating disorders scored significantly higher on sleep disorder scales, and reported significantly more impairment of daytime functioning.

Persistence of poor sleep predicts the severity of the clinical condition after 6months of standard treatment in patients with eating disorders

Clinical evidence suggests that eating disorder (ED) patients experience poor sleep even if they rarely complain of it. However, direct empirical evidence supporting this relationship is still sparse. In order to provide direct evidence, poor sleep, severity of the ED symptoms and depression were obtained in 562 ED patients at treatment admission (T0). For 271 patients out of them, data were also available after 6months of standard treatment (T1). Results evidence that at T0 poor sleep predicts severity of ED symptoms through the mediation of depression. Persistence of poor sleep at T1 directly predicts the severity of the ED symptoms both directly and through the mediation of depression. These findings suggest that the treatment of ED may benefit from addressing poor sleep since its presence and persistence increase comorbidity and attrition to the standard treatment.

Current and previous eating practices among women recovered from anorexia nervosa: a qualitative approach

OBJECTIVE: The aim of this study was to analyze qualitatively how women, who have recovered from anorexia nervosa, perceive and describe their current eating practices, as well as the ones developed during the eating disorder period. METHODS: Seven women were interviewed individually with the objective of investigating their eating practices, transition phases and all relevant aspects that somewhat contributed to the habit-forming; experiences, feelings and perceptions related to mealtime and the influence that food has had over the present subjects' life. The interviews were analyzed by the discourse of the collective subject method. RESULTS: The results brought up the following topics: a) control; b) concerns and feelings; c) deprivation d) beauty dictatorship; e) eating competence; f) importance of food; g) food cacophony. CONCLUSIONS: What stands out is a multiplicity of eating practices, which during the eating disorder were similar to and characterized by restriction; however, after recovery, part of the subjects seem to have developed a higher eating competence, whereas others show a practice similar to the one acquired during the anorexia nervosa, such as the difficulty in realizing when they are satisfied and a feeling of discomfort when facing social interactions.

Electroencephalography in eating disorders

Clinical applications of electroencephalography (EEG) are used with different objectives, EEG being a noninvasive and painless procedure. In respect of eating disorders, in the 1950s a new line of study about the neurological bases of anorexia nervosa was started and has since been developed. The purpose of this review is to update the existing literature data on the main findings in respect of EEG in eating disorders by means of a search conducted in PubMed. Despite the fact that weight gain tends to normalize some brain dysfunctions assessed by means of EEG, the specific effect of gaining weight remains controversial. Different studies have reported that cortical dysfunctions can be found in patients with anorexia nervosa even after weight gain, whereas others have reported a normalization of EEG in respect of the initial reduced alpha/ increased beta power in those patients with refeeding. Findings of studies that have analyzed the possible relationship between eating disorders and depression, based on sleep EEG disturbances, do not support the idea of eating disorders as a variant of depression or affective disorders. Some EEG findings are very consistent with previous neuroimaging results on patients with anorexia nervosa, reporting neural disturbances in response to stimuli that are relevant to the pathology (eg, stimuli like food exposure, different emotional situations, or body images).

Comparison of nutrient intake by sleep status in selected adults in Mysore, India

Insomnia has become a major public health issue in recent times. Although quality of sleep is affected by environmental, psychophysiological, and pharmacological factors, diet and nutrient intake also contribute to sleep problems. This study investigated the association between nutrient intake and co-morbid symptoms associated with sleep status among selected adults. Subjects in this study included 87 men and women aged 21-45 years. Presence of insomnia was assessed using the Insomnia Screening Questionnaire, and dietary intake was measured over three consecutive days by dietary survey. Descriptive analysis, ANOVA, and Chi-Square tests were performed to compute and interpret the data. Approximately 60% of the participants were insomniacs. People with insomnia consumed significantly lesser quantities of nutrients as compared to normal sleepers. Differences in intakes of energy, carbohydrates, folic acid, and B₁₂ were highly significant (P < 0.002). Further, intakes of protein, fat, and thiamine were significantly different (P < 0.021) between insomniacs and normal sleepers. The nutrient intake pattern of the insomniacs with co-morbid symptoms was quite different from that of the normal sleepers. Based on these results, it is probable that there is an association between nutrition deficiency, co-morbid symptoms, and sleep status. More studies are required to confirm these results.

Sleep disturbances, body mass index and eating behaviour in undergraduate students

This study investigates the association between sleep disturbances, body mass index (BMI) and eating behaviour in a sample of undergraduate students. The sample comprises 870 medicine and dentistry students from Coimbra University (62.5% females), aged between 17 and 25 years. The Eating Attitudes Test-40 was used to measure eating behaviour, and two questions were applied addressing difficulties of initiating sleep (DIS) and difficulties of maintaining sleep (DMS). A sleep disturbance index (SDI) was calculated from the sum of DIS and DMS scores. Body mass index (BMI) was determined from self-reported weight and height. The correlation analyses generally indicated that global eating disturbance, bulimic behaviour dimension and social pressure to eat were associated particularly with sleep difficulties. An association between diet concerns and sleep difficulties was less consistent. Regression analyses showed that bulimic behaviour (BB) and social pressure to eat (SPE) dimensions were associated significantly with sleep difficulties (DIS, DMS, SDI) in the total sample (BB: from P<0.01 to P<0.001; SPE: P<0.05) and in males (BB: from P<0.05 to P<0.001; SPE: P<0.05) and with insomnia symptoms (P<0.01). In females, bulimic behaviour was the only factor associated significantly with sleep difficulties (SDI, DIS; P<0.01) and with insomnia symptoms (P<0.05). Although BMI was correlated negatively with sleep difficulties (P<0.05), regression analyses indicated that it was not associated significantly with them. Our findings support an association between eating behaviour and sleep disturbances in both genders, which may have treatment implications.

Hypothalamic orexin neurons regulate arousal according to energy balance in mice

Mammals respond to reduced food availability by becoming more wakeful and active, yet the central pathways regulating arousal and instinctual motor programs (such as food seeking) according to homeostatic need are not well understood. We demonstrate that hypothalamic orexin neurons monitor indicators of energy balance and mediate adaptive augmentation of arousal in response to fasting. Activity of isolated orexin neurons is inhibited by glucose and leptin and stimulated by ghrelin. Orexin expression of normal and ob/ob mice correlates negatively with changes in blood glucose, leptin, and food intake. Transgenic mice, in which orexin neurons are ablated, fail to respond to fasting with increased wakefulness and activity. These findings indicate that orexin neurons provide a crucial link between energy balance and arousal.

To eat or to sleep? Orexin in the regulation of feeding and wakefulness

Orexin-A and orexin-B are neuropeptides originally identified as endogenous ligands for two orphan G-protein-coupled receptors. Orexin neuropeptides (also known as hypocretins) are produced by a small group of neurons in the lateral hypothalamic and perifornical areas, a region classically implicated in the control of mammalian feeding behavior. Orexin neurons project throughout the central nervous system (CNS) to nuclei known to be important in the control of feeding, sleep-wakefulness, neuroendocrine homeostasis, and autonomic regulation. orexin mRNA expression is upregulated by fasting and insulin-induced hypoglycemia. C-fos expression in orexin neurons, an indicator of neuronal activation, is positively correlated with wakefulness and negatively correlated with rapid eye movement (REM) and non-REM sleep states. Intracerebroventricular administration of orexins has been shown to significantly increase food consumption, wakefulness, and locomotor activity in rodent models. Conversely, an orexin receptor antagonist inhibits food consumption. Targeted disruption of the orexin gene in mice produces a syndrome remarkably similar to human and canine narcolepsy, a sleep disorder characterized by excessive daytime sleepiness, cataplexy, and other pathological manifestations of the intrusion of REM sleep-related features into wakefulness. Furthermore, orexin knockout mice are hypophagic compared with weight and age-matched littermates, suggesting a role in modulating energy metabolism. These findings suggest that the orexin neuropeptide system plays a significant role in feeding and sleep-wakefulness regulation, possibly by coordinating the complex behavioral and physiologic responses of these complementary homeostatic functions.

Sleep-wake monitoring in women suffering from anorexia nervosa

There is evidence that some Anorexia Nervosa (AN) patients have sleep abnormalities. No studies of their sleep-wake cycles in a natural environment have yet been reported. The purpose of this study was to evaluate an objective and subjective sleep-wake cycle of AN patients compared to a healthy age-equated control group (CON). Twenty-one AN female and sixteen CON female subjects were recruited. Sleep-wake patterns were monitored using ambulatory monitoring mini-actigraphs for one week. Each subject completed self-report questionnaires. The self-report questionnaires revealed significantly more sleep disturbances in AN than CON, whereas the ambulatory sleep data revealed no significant differences between the two groups in sleep-wake cycle.

Improved physical fitness failed to alter the EEG patterns of sleep in young women

We investigated the effect of a 12-week physical training programme on the sleep of nine unfit women. Data were collected at 0, 4, 8 and 12 weeks of the training programme. Changes in fitness were assessed by changes in maximal oxygen consumption (VO2max) and onset of blood lactate turn point (LTP). Lean body mass (LBM) was calculated from total body potassium measurements. The all-night sleep recordings were made following days during which the subjects carried out their normal daily routines and did no extra exercise. Although cardiorespiratory fitness improved significantly as indicated by an increase in both VO2max and LTP, there was no change in LBM. The improvement in cardiorespiratory fitness did not result in any changes in the sleep parameters measured. Other workers have reported an improvement in sleep quality in eight army recruits during their basic training. The male recruits showed improved cardiorespiratory fitness and an increase in muscle bulk. These results suggest that increased fitness only facilitates sleep when there is an associated increase in LBM. Alternatively it may be that the response of sleep to improved fitness is sex-linked.

Depression as a correlate of starvation in patients with eating disorders

The relationship between depressive symptoms and starvation, reflected by body weight and biochemical parameters, was investigated in 64 patients fulfilling DSM-III criteria for anorexia nervosa or bulimia. Multiple regression analysis revealed significant effects of body weight and beta-hydroxybutyric acid, respectively, on such specific depressive symptoms as depressed or dysphoric mood when controlling for severity of psychopathology of the eating disorder.

Major affective disorder in anorexia nervosa and bulimia. A descriptive diagnostic study

DSM-III lifetime diagnoses were assessed in 52 patients with a lifetime history of anorexia nervosa or bulimia by means of a standardised diagnostic interview. It was found that 44.2% had a lifetime diagnosis of DSM-III major affective disorder, with abstaining anorectics having a lower rate of depression than those with bulimic symptoms. In the great majority of cases, the onset of affective disorder post-dated the onset of the eating disorder by at least one year. In patients whose eating disorder was in remission, the rate of depressive symptoms was lower than in those in the acute stage of their illness. These findings, combined with recent studies on biological changes in eating disorders, and psychological theories of depression, suggest that in most cases in which the two conditions are associated, the depression is secondary to the eating disorder.

EEG-monitored sleep in anorexia nervosa and bulimia

We compared the EEG-monitored sleep of 8 women with anorexia nervosa and 16 normal weight women with bulimia to that of 14 normal women. The patients with anorexia nervosa spent less time asleep and spent less of their sleep time in Stage 1. The sleep of the normal weight patients with bulimia was remarkably similar to that of the controls. These data suggest that most patients with anorexia nervosa and bulimia do not exhibit the type of sleep disturbances characteristic of patients with major depressive illness.

Psychiatry and endocrinology: an expanding interface

There is growing documentation that a variety of hormones can both influence mood and behavior and be affected by them. Endocrine measures thus provide us with a readily accessible source of information about how the brain mediates between stimuli arising from the external social environment, intrapsychic phenomena, and the body's internal physiological needs. This paper will review recent psychoendocrine research which has in particular suggested several new concepts: (1) the brain itself might be viewed as a "target organ" for certain hormones; (2) specific hormonal correlates of certain clinical psychiatric syndromes, such as anorexia nervosa and depressive illness, might serve as biological markers which could help in the differential diagnosis of these conditions; and (3) peripheral hormonal determinations, by virtue of the role played by central nervous system (CNS) neurotransmitters in endocrine regulation, may provide important specific information about possible CNS biogenic amine abnormalities associated with the pathogenesis of certain psychiatric disorders.

Anorexia nervosa: dietary treatment and re-establishment of body weight in 20 cases studied on a metabolic unit

This paper reviews the nutritional treatment and weight progress of 20 patients with anorexia nervosa studied in a teaching hospital metabolic unit between January 1974 and August 1977. The classification of patients, their pre-admission dietary intakes and weight status are compared. The method of re-establishing weight by closely monitored normal nutrition under conditions of bedrest and chlorpromazine medication are described. It is illustrated by the progress of one 14-year-old girl patient and the study of the rate of increase in weight of the whole group. Satisfactory weight levels were attained by all patients with acceptable time limits.

The immediate effects of intravenous specific nutrients on EEG sleep

This study examined the immediate influence of intravenous amino acids and glucose on sleep as measured by all-night EEG recording. The study on 9 normal female subjects was of a latin-square design. Slow wave sleep (SWS) was increased by both solutions whilst dream sleep (REM) was decreased by amino acids and increased by glucose. Total sleep time was not affected. Subjective feelings as to restlessness, quality and depth of sleep under the impact of the various solutions were gathered. The work further elucidates the effect of nutrition on sleep and supports certain theories as to the function of the main sleep component.

Sleep in the rat during food deprivation and subsequent restitution of food

Continuous telemetric EEG recordings served to determine the vigilance states of the rat during 2 control days, 80 h of food deprivation and 64 h following restitution of food. The recordings were supplemented by measurements of food intake, water intake and motor activity. The following 3 sleep parameters were not significantly changed by food deprivation: the daily amount of the vigilance states, the light-dark distribution of sleep and waking, and the 10 min paradoxical sleep (PS) cycle. During food deprivation, PS was depressed in the dark phase of the diurnal cycle and increased in the light phase. The sleep parameter that was most affected by food deprivation was the duration of sleep episodes. Episodes of slow-wave sleep (SWS) and PS were shortened only in the dark phase of the deprivation days, whereas total sleep episodes were progressively decreased in both diurnal phases. After restitution of food, the episodes of SWS and total sleep were immediately lengthened and tended to exceed the control level. The duration of feeding episodes and meal size were significantly increased in comparison to pre-deprivation values, whereas feeding frequency was decreased. Long episodes of continuous motor activity occurred during the dark phase of the refeeding period, while a fragmented activity pattern was typical for the deprivation nights. It is proposed that the adjustment of the length of behavioral episodes may constitute an important adaptive mechanism for the rat.

Study of EEG sleep characteristics in patients with anorexia nervosa before and after restoration of matched population mean weight consequent on ingestion of a "normal" diet

This experimental study confirms that insomnia and especially early morning waking is associated with low body weight in anorexia nervosa. It extends the view that there is a relationship between reduced nutritional intake and consequent change in weight and sleep disturbance. This relationship was studied by comparison of certain sleep EEG parameters in a group of hospitalized anorexia nervosa patients before and after a regime of re-feeding to matched population mean weight on a ‘normal’ diet. At low body weights, the patients had less sleep and more restlessness, especially in the last 4 hr of the night. After weight gain, there was a significant increase in length of sleep and REM sleep. The implications of these results are discussed with particular reference to an association between various anabolic profiles and differing need for REM sleep.

Isocaloric diet changes and electroencephalographic sleep

Electroencephalographic (E.E.G.) sleep changes were studied in eight young healthy male subjects who were given a normal balanced diet or a high-carbohydrate/low-fat or low-carbohydrate/high-fat isocaloric diet, according to an experimental design. Significantly less slow-wave sleep (S.W.S.) was found after consuming a high-carbohydrate/low-fat diet than after consuming a normal balanced diet or a low-carbohydrate/high-fat diet. The latter two diets did not differ in terms of the amounts of S.W.S. Both high-carbohydrate/low-fat and low-carbohydrate/high-fat isocaloric diets, especially the former, were associated with significantly more rapid-eye-movement (R.E.M.) sleep than was the normal balanced diet. These findings emphasise the importance of daily diet for the following night's sleep.

On the function of sleep

It is proposed that sleep serves the function of maintaining immobility in animals at times when immobility is an optimum behavioural survival strategem. Sleep is of great evolutionary age and is always carefully tailored to the life-style of each animal; abundant in some species and absent from others. The survival advantages conferred on an animal by the power of sleep to schedule behaviour effectively may justify its existence and persistence in the evolution of species.

Plasma tryptophan and sheep

Free, bound, and total plasma tryptophan (F.P.T., B.P.T., and T.P.T.) levels have been measured throughout the night in six young female volunteers. All-night polygraphic sleep recordings were also made. No direct temporal relationship was found between plasma tryptophan levels and specific sleep stages. The mean F.P.T. levels, however, were found to have a positive correlation with rapid-eye-movement (R.E.M.) sleep and a negative correlation with non-R.E.M. sleep. An inverse relationship existed between the F.P.T. and B.P.T. levels. There appeared to be a diurnal variation in F.P.T. levels, with high readings in the first half of the night.

Aspects of the relationship between sleep and nutrition: a study of 375 psychiatric out-patients

Weight change and sleep disturbance are well documented features of psychiatric illness. Complaint about difficulty in getting off to sleep is a common feature of neurotic illness, especially anxiety states. Early morning waking has for many years been regarded by some as a clinical feature—almost a diagnostic pointer—for ‘endogenous depression‘. Motor restlessness is also commonly described as a feature of this disorder. However, other clinicians have concluded that such depressive illness is merely one end of the spectrum of the depressive response. In particular, McGhie (1966) has shown that sleep disturbances of all kinds, as reported by the patients themselves, may occur in a variety of psychiatric illnesses. For instance he found that early morning waking was reported in 16 per cent of non-depressed psychiatric patients as distinct from 17 per cent of patients presenting with depression. Moreover, Hinton (1963) has shown that early morning waking when carefully measured does not specifically characterize those types of depressive illness described by others as ‘endogenous', but that it can occur in all types of depressive illness. He also reported his observation that sleep disturbance amongst depressed patients is mostly related to the phenomenon of agitation. Agitated patients lost more sleep, most apparent in the latter part of the night. On the other hand Carney et al. (1965), in their study of over 100 patients with depression, found that certain symptoms clustered into two groups reflecting the usual concepts of ‘endogenous' and ‘neurotic’ depression respectively. Early morning waking and weight loss were important characteristics of their group of patients designated ‘endogenous' depression, and were regarded as important indicators for them of the value of ECT. There was a positive inter-symptom correlation of 0.234 between weight loss (7 lb.+) and early waking. Most studies do not suggest a causal link between weight change and sleep disturbance, but by inference regard these features as being more integral aspects of an underlying biological factor which also promotes the disturbed mood.

Sleep after a bedtime beverage

Sleep after an inert capsule was compared with sleep after a hot, bedtime, milk-cereal drink (Horlicks). All-night electrophysiological recordings were made with 18 persons on 10 nights each.Restlessness during sleep at the end of the night was diminished after Horlicks in a group of 10 young adults. In an older group of eight adults, mean age 55 years, sleep after Horlicks was of longer total duration and was less broken by periods of wakefulness. In the latter group the improvement associated with Horlicks was most apparent late in the night and it increased with repeated administration.

Primary anorexia nervosa or weight phobia in the male: report on 13 cases

The cases of 13 men with anorexia nervosa are reported. While the disorder as seen in the clinic is much less common in males than females this may not be a true reflection of the differential sex or overall prevalence rates. The disorder is found to have the same basic characteristics in the male as in the female: namely, a phobic avoidance of normal weight associated with elective carbohydrate starvation and emaciation. As in the female the mechanism appears to develop out of normal adolescent dieting behaviour and to arise as a means of avoiding overwhelming psychosocial maturational demands of adolescence. Premorbid and family features include a state of overnutrition and a high degree of family psychopathology reflected in high rates of parental psychiatric morbidity and marital difficulty.