Intranasal oxytocin in the treatment of anorexia nervosa: Randomized controlled trial during re-feeding

Potential mechanisms underlying the association between feeding and eating disorders and autism

There is a reliable association between autism and Feeding and Eating Disorders. Concerningly, where these two conditions co-occur, clinical outcomes of Feeding and Eating Disorders are significantly worse, and treatment less effective, than when the Feeding and Eating Disorders occur in neurotypical individuals. Problematically, the reason for the association between autism and Feeding and Eating Disorders is poorly understood, which constrains advances in clinical care. This paper outlines several possible mechanisms that may underlie the observed association and suggests ways in which they may be empirically tested. Mechanisms are split into those producing an artefactual association, and those reflecting a genuine link between conditions. Artefactual associations may be due to conceptual overlap in both diagnostic criteria and measurement, Feeding and Eating Disorders causing transient autistic traits, or the association being non-specific in nature. A genuine association between autism and Feeding and Eating Disorders may be due to common causal factors, autism directly or indirectly causing Feeding and Eating Disorders, and Feeding and Eating Disorders being a female manifestation of autism.

A phase II randomised controlled trial of intranasal oxytocin in anorexia nervosa

BACKGROUND

Anorexia nervosa (AN) is an eating disorder (ED) with high mortality rates and limited response to existing treatments, prompting the need to identify effective agents and adjuncts. There is evidence for an emerging role for the neuropeptide oxytocin (OT) in the pathophysiology of AN, with studies showing a perturbed oxytocinergic system in patients with AN. Preliminary evidence has demonstrated that intranasal OT (IN-OT) can produce anxiolytic effects in AN, as well as reducing concern about eating, and dysfunctional attentional biases related to the disorder. IN-OT is a non-invasive treatment option for AN that requires investigation as an adjunct to nutritional rehabilitation.

METHODS

This multi-site study (Trial Registration:ACTRN1261000897460) sought to replicate and extend a previous randomised placebo-controlled pilot trial of repeated dose IN-OT in patients with AN hospitalised for nutritional rehabilitation. Patients with AN (N=61) received daily IN-OT (18 IU twice per day) or placebo for four weeks, whilst undergoing inpatient hospital treatment. Outcome measures included ED psychopathology (primary) as measured by the Eating Disorder Examination (EDE) and Body Mass Index (BMI; secondary). Participants were assessed pre- and post-treatment, and at six months following the intervention. The effects of the first and last doses of IN-OT on responses (anxiety ratings and salivary cortisol) to a high-energy snack were also examined.

RESULTS

Sixty-one female inpatients (Mage=24.36,SD=7.87) with an average BMI of 16.24 (range: 11.43-18.55), were recruited into the study. No significant differences were found between placebo and OT groups at any of the time points on the outcomes of interest, but significant improvements in almost all psychological parameters in both groups were evident over time. IN-OT did not significantly reduce anxiety nor salivary cortisol in response to a high-calorie snack.

CONCLUSION

This is the largest randomised placebo-controlled trial of repeated dose intranasal OT in people with AN, during refeeding. The therapeutically promising findings of the pilot study were not replicated. Limitations and reasons for the non-replication included relatively large variance, baseline psychopathology scores being higher in this patient group, potential ceiling effects in BMI and ED psychopathology as well as differing comorbidities.

The impact of oxytocin on emotion recognition and trust: Does disordered eating moderate these relationships?

OBJECTIVES

The current study aimed to investigate the impact of oxytocin on emotion recognition, trust, body image, affect, and anxiety and whether eating disorder (ED) symptoms moderated any of these relationships.

METHOD

Participants (n = 149) were female university students, who were randomly allocated to receive in a double-blind nature, a single dose of oxytocin intranasal spray (n = 76) or a placebo (saline) intranasal spray (n = 73). Participants were asked to complete an experimental measure of emotion recognition and an investor task aimed to assess trust.

RESULTS

The oxytocin group exhibited better overall performance on the emotion recognition task (especially with recognising positive emotions), and a decline in state positive affect than the control group at post-intervention. However, these effects were not moderated by ED symptom severity, nor were effects found for state anxiety, negative affect, body image and recognising negative emotions in the emotion recognition task.

CONCLUSION

The current findings contribute to the growing literature on oxytocin, emotion recognition and positive affect and suggest that ED pathology does not moderate these relationships. Future research would benefit from examining the efficacy of an oxytocin intervention using a within-subjects, cross-over design, in those with sub-clinical and clinical EDs, as well as healthy controls.

Effects of cannabidiol on psychosocial stress, situational anxiety and nausea in a virtual reality environment: a protocol for a single-centre randomised clinical trial

INTRODUCTION

The non-intoxicating plant-derived cannabinoid, cannabidiol (CBD), has demonstrated therapeutic potential in a number of clinical conditions. Most successful clinical trials have used relatively high (≥300 mg) oral doses of CBD. Relatively few studies have investigated the efficacy of lower (<300 mg) oral doses, typical of those available in over-the-counter CBD products.

METHODS

We present a protocol for a randomised, double-blind, placebo-controlled, parallel-group clinical trial investigating the effects of a low oral dose (150 mg) of CBD on acute psychosocial stress, situational anxiety, motion sickness and cybersickness in healthy individuals. Participants (n=74) will receive 150 mg of CBD or a matched placebo 90 min before completing three virtual reality (VR) challenges (tasks) designed to induce transient stress and motion sickness: (a) a 15 min 'Public Speaking' task; (b) a 5 min 'Walk the Plank' task (above a sheer drop); and (c) a 5 min 'Rollercoaster Ride' task. The primary outcomes will be self-reported stress and nausea measured on 100 mm Visual Analogue Scales. Secondary outcomes will include salivary cortisol concentrations, skin conductance, heart rate and vomiting episodes (if any). Statistical analyses will test the hypothesis that CBD reduces nausea and attenuates subjective, endocrine and physiological responses to stress compared with placebo. This study will indicate whether low-dose oral CBD has positive effects in reducing acute psychosocial stress, situational anxiety, motion sickness and cybersickness.

ETHICS AND DISSEMINATION

The University of Sydney Human Research Ethics Committee has granted approval (2023/307, version 1.6, 16 February 2024). Study findings will be disseminated in a peer-reviewed journal and at academic conferences.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry (ACTRN12623000872639).

The neurohypophyseal hormone oxytocin and eating behaviors: a narrative review

BACKGROUND

The neuropeptide oxytocin (OT) is crucial in several conditions, such as lactation, parturition, mother-infant interaction, and psychosocial function. Moreover, OT may be involved in the regulation of eating behaviors.

METHODS

This review briefly summarizes data concerning the role of OT in eating behaviors. Appropriate keywords and medical subject headings were identified and searched for in PubMed/MEDLINE. References of original articles and reviews were screened, examined, and selected.

RESULTS

Hypothalamic OT-secreting neurons project to different cerebral areas controlling eating behaviors, such as the amygdala, area postrema, nucleus of the solitary tract, and dorsal motor nucleus of the vagus nerve. Intracerebral/ventricular OT administration decreases food intake and body weight in wild and genetically obese rats. OT may alter food intake and the quality of meals, especially carbohydrates and sweets, in humans.

DISCUSSION

OT may play a role in the pathophysiology of eating disorders with potential therapeutic perspectives. In obese patients and those with certain eating disorders, such as bulimia nervosa or binge/compulsive eating, OT may reduce appetite and caloric consumption. Conversely, OT administered to patients with anorexia nervosa may paradoxically stimulate appetite, possibly by lowering anxiety which usually complicates the management of these patients. Nevertheless, OT administration (e.g., intranasal route) is not always associated with clinical benefit, probably because intranasally administered OT fails to achieve therapeutic intracerebral levels of the hormone.

CONCLUSION

OT administration could play a therapeutic role in managing eating disorders and disordered eating. However, specific studies are needed to clarify this issue with regard to dose-finding and route and administration time.

Pharmacological Studies in Eating Disorders: A Historical Review

Eating disorders (EDs) are serious mental health conditions characterised by impaired eating behaviours and nutrition as well as disturbed body image, entailing considerable mortality and morbidity. Psychopharmacological medication is an important component in the treatment of EDs. In this review, we performed a historic analysis of pharmacotherapeutic research in EDs based on the scientific studies included in the recently published World Federation of Societies for Biological Psychiatry (WFSBP) guidelines for ED treatment. This analysis focuses on early approaches and trends in the methods of clinical pharmacological research in EDs, for example, the sample sizes of randomised controlled trials (RCTs). We found the development of psychopharmacological treatments for EDs followed advancements in psychiatric pharmacotherapy. However, the application of RCTs to the study of pharmacotherapy for EDs may be an impediment as limited participant numbers and inadequate research funding impede generalisability and statistical power. Moreover, current medication usage often deviates from guideline recommendations. In conclusion, the RCT model may not effectively capture the complexities of ED treatment, and funding limitations hinder research activity. Novel genetically/biologically based treatments are warranted. A more comprehensive understanding of EDs and individualised approaches should guide research and drug development for improved treatment outcomes.

The use of intranasal oxytocin in the treatment of eating disorders

Oxytocin (OXT) is a hypothalamic peptide that plays a number of roles in the body, being involved in labor and lactation, as well as cognitive-emotional processes and social behavior. In recent years, knowledge of the physiology of OXT has been repeatedly used to explore its potential role in the treatment of numerous diseases, identifying a significant role for OXT in appetite regulation, eating behavior, weight regulation, and food-related beliefs. In this review we provide an overview of publications on this topic, but due to the wealth of research, we have limited our focus to studies based on the use of intranasal OXT in psychiatric diseases, with a particular focus on the role of oxytocin in eating disorders and obesity. Accumulating evidence that OXT intranasal supplementation may provide some therapeutic benefit seems promising. In individuals with autistic spectrum disorders (ASD) and schizophrenia, OXT may affect core deficits, improving social cognition and reducing symptom severity in schizophrenia. Dysregulation of serum and CSF OXT levels, as well as polymorphisms of its genes, may affect emotion perception in patients with eating disorders and correlate with co-occurring depressive and anxiety disorders. Nevertheless, there are still many critical questions regarding the pharmacokinetics and pharmacodynamics of intranasal OXT that can only be answered in larger randomized controlled trials.

Neuroendocrine adaptations to starvation

Famine and starvation have punctuated the evolutionary past of the human species. As such, we have developed hormonal responses to undernutrition that minimize energy expenditure on processes that are not critical for the survival of the individual, such as reproduction. In this review, we discuss neuroendocrine adaptations to starvation including hypogonadotropic hypogonadism, growth hormone resistance, hypercortisolemia, and the downregulation of the hypothalamic-pituitary-thyroid axis. We review the time-course of these adaptations by describing studies involving the short-term fasting of healthy individuals as well as studies describing the hormonal changes in states of chronic undernutrition, using individuals with anorexia nervosa as a model of chronic starvation. Lastly, we review representative clinical effects of chronic undernutrition.

Microbes, oxytocin and stress: Converging players regulating eating behavior

Oxytocin is a peptide-hormone extensively studied for its multifaceted biological functions and has recently gained attention for its role in eating behavior, through its action as an anorexigenic neuropeptide. Moreover, the gut microbiota is involved in oxytocinergic signaling through the brain-gut axis, specifically in the regulation of social behavior. The gut microbiota is also implicated in appetite regulation and is postulated to play a role in central regulation of hedonic eating. In this review, we provide an overview on oxytocin and its individual links with the microbiome, the homeostatic and non-homeostatic regulation of eating behavior as well as social behavior and stress.

Pharmacotherapy, alternative and adjunctive therapies for eating disorders: findings from a rapid review

BACKGROUND

The current review broadly summarises the evidence base for pharmacotherapies and adjunctive and alternative therapies in the treatment of eating disorders and disordered eating.

METHODS

This paper forms part of a Rapid Review series examining the evidence base in the field of eating disorders. This was conducted to inform the Australian National Eating Disorder Research and Translation Strategy 2021-2030. ScienceDirect, PubMed and Ovid/Medline were searched for included studies published between 2009 and 2021 in English. High-level evidence such as meta-analyses, large population studies and randomised control trials were prioritised, and grey literature excluded. Data from included studies relating to pharmacotherapy, and to adjunctive and alternative therapies in eating disorders, were synthesised and disseminated in the current review.

RESULTS

A total of 121 studies were identified, relating to pharmacotherapy (n = 90), adjunctive therapies (n = 21) and alternative therapies (n = 22). Some of the identified studies involved combinations of the above (e.g. adjunctive pharmacotherapy). Evidence of efficacy of interventions across all three categories was very limited with few relevant high quality clinical trials. There was a particular scarcity of evidence around effective treatments for anorexia nervosa (AN). With treatment of bulimia nervosa (BN), fluoxetine has exhibited some efficacy leading to regulatory approval in some countries. With binge eating disorder (BED), recent evidence supports the use of lisdexamfetamine. Neurostimulation interventions show some emerging efficacy in the treatment of AN, BN and BED but some, such as deep brain stimulation can be highly invasive.

CONCLUSION

Despite widespread use of medications, this Rapid Review has identified a lack of effective medications and adjunctive and alternative therapies in the treatment of EDs. An intensification of high-quality clinical trial activity and drug discovery innovation are required to better assist patients suffering from EDs.

Impact of virtual adjunctive cognitive remediation therapy on cognitive flexibility and treatment outcomes in comorbid anorexia nervosa and exercise dependence as quantified using novel biomarkers: A stage 1 registered report

OBJECTIVE

Anorexia nervosa (AN) is associated with significant individual mental and physical suffering and public health burden and fewer than half of patients recover fully with current treatments. Comorbid exercise dependence (ExD) is common in AN and associated with significantly worse symptom severity and treatment outcomes. Research points to cognitive inflexibility as a prominent executive function inefficiency and transdiagnostic etiologic and maintaining mechanism linking AN and ExD. This study will evaluate the initial efficacy of adjunctive Cognitive Remediation Therapy (CRT), which has been shown to produce cognitive improvements in adults with AN, in targeting cognitive inflexibility in individuals with comorbid AN and ExD. As an exploratory aim, this study also addresses the current lack of quick and cost-effective assessments of cognitive flexibility by establishing the utility of two proposed biomarkers, heart rate variability and salivary oxytocin.

METHOD

We will conduct a single-group, within-subjects trial of an established CRT protocol delivered remotely as an adjunct to inpatient or intensive outpatient treatment as usual (TAU) to adult patients (n = 42) with comorbid AN and ExD. Assessments, including self-report, neuropsychological, and biomarker measurements, will occur at three time points.

RESULTS

We expect CRT to increase cognitive flexibility transdiagnostically and consequently, along with TAU, positively impact AN and ExD compulsivity and symptom severity, including weight gain.

DISCUSSION

Findings will inform the development of more effective integrative interventions for AN and ExD targeting shared mechanisms and facilitate the routine assessment of cognitive flexibility as a transdiagnostic risk and maintaining factor across psychopathologies in clinical and research settings.

PUBLIC SIGNIFICANCE

Patients with anorexia nervosa often engage in excessive exercise, leading to harmful outcomes, including increased suicidal behavior. This study examines the preliminary efficacy of an intervention that fosters flexible and holistic thinking in patients with problematic eating and exercise to, along with routine treatment, decrease harmful exercise symptoms. This study also examines new biological markers of the inflexible thinking style thought to be characteristic of anorexia nervosa and exercise dependence.

Oxytocin and eating disorders: Knowledge gaps and future directions

Eating disorders continue to be a major public health issue and important cause of morbidity and premature mortality, particularly for young people. Yet in a concerning dialectic, this occurs in the context of an epidemic of obesity which, with its medical complications, constitutes another vexing public health challenge. While it is not an eating disorder per se obesity is often comorbid with eating disorders. Effective treatment for both eating disorders and obesity has proven to be elusive and in the search for novel therapeutic interventions, the prosocial, anxiolytic, brain plasticity and metabolic effects of oxytocin (OT) have been examined from this perspective. The availability of intranasal oxytocin (IN-OT) has led to a number of interventional treatment studies in anorexia nervosa (AN), bulimia nervosa (BN), binge eating disorder (BED), their atypical and subclinical forms and in medical and psychiatric conditions co-occurring or comorbid with these, obesity with BED would be included here. The aim of this mini review is to collate recent findings on OT as a novel therapeutic intervention in eating disorders and obesity and to identify and address some of the knowledge gaps in the use of IN-OT. The wider clinical perspective utilised here might better address some of the gaps and identify future directions of research. Clearly much remains to be done for OT to fulfil its therapeutic promise in eating disorders. OT might yet be of therapeutic promise and will be appreciated where treatment advances have been hard to come by and prevention challenging for these disorders.

World Federation of Societies of Biological Psychiatry (WFSBP) guidelines update 2023 on the pharmacological treatment of eating disorders

OBJECTIVES

This 2023 update of the WFSBP guidelines for the pharmacological treatment of eating disorders (EDs) reflects the latest diagnostic and psychopharmacological progress and the improved WFSBP recommendations for the assessment of the level of evidence (LoE) and the grade of recommendation (GoR).

METHODS

The WFSBP Task Force EDs reviewed the relevant literature and provided a timely grading of the LoE and the GoR.

RESULTS

In anorexia nervosa (AN), only a limited recommendation (LoE: A; GoR: 2) for olanzapine can be given, because the available evidence is restricted to weight gain, and its effect on psychopathology is less clear. In bulimia nervosa (BN), the current literature prompts a recommendation for fluoxetine (LoE: A; GoR: 1) or topiramate (LoE: A; GoR: 1). In binge-eating disorder (BED), lisdexamfetamine (LDX; LoE: A; GoR: 1) or topiramate (LoE: A; GoR: 1) can be recommended. There is only sparse evidence for the drug treatment of avoidant restrictive food intake disorder (ARFID), pica, and rumination disorder (RD).

CONCLUSION

In BN, fluoxetine, and topiramate, and in BED, LDX and topiramate can be recommended. Despite the published evidence, olanzapine and topiramate have not received marketing authorisation for use in EDs from any medicine regulatory agency.

Emerging therapeutic targets for anorexia nervosa

INTRODUCTION

Anorexia nervosa is a frequent eating disorder that affects predominantly young women and may take a severe and chronically worsening course of disease contributing to its high mortality rate. Although a multitude of treatment options exist, this disease still bears a high relapse rate. In light of these facts, an improvement of existing and development of new treatment targets and options is warranted.

AREAS COVERED

The present review article covers recent developments in psychotherapy associated with the respective neuropsychological and brain alterations as well as highlights current and future pharmacotherapeutic options.

EXPERT OPINION

Several encouraging developments in the field of psychotherapy such as interventions targeting neurocognitive profiles or addressing reward processing, brain stimulation as well as pharmacological modulation of hormones, namely leptin, oxytocin, ghrelin and nesfatin-1 signaling might be - most likely as part of a multimodal treatment approach - efficacious in order to improve treatment of patients with anorexia nervosa, especially those with a severe course of disease as well as comorbidities. As anorexia nervosa represents a complex and severe mental disorder, it seems most likely that a combination and integration of different evidence-based treatment approaches and settings will contribute to an improved prognosis of this eating disorder. This should be further explored in future studies.

Nose-to-Brain Delivery of Therapeutic Peptides as Nasal Aerosols

Central nervous system (CNS) disorders, such as psychiatric disorders, neurodegeneration, chronic pain, stroke, brain tumor, spinal cord injury, and many other CNS diseases, would hugely benefit from specific and potent peptide pharmaceuticals and their low inherent toxicity. The delivery of peptides to the brain is challenging due to their low metabolic stability, which decreases their duration of action, poor penetration of the blood-brain barrier (BBB), and their incompatibility with oral administration, typically resulting in the need for parenteral administration. These challenges limit peptides’ clinical application and explain the interest in alternative routes of peptide administration, particularly nose-to-brain (N-to-B) delivery, which allows protein and peptide drugs to reach the brain noninvasively. N-to-B delivery can be a convenient method for rapidly targeting the CNS, bypassing the BBB, and minimizing systemic exposure; the olfactory and trigeminal nerves provide a unique pathway to the brain and the external environment. This review highlights the intranasal delivery of drugs, focusing on peptide delivery, illustrating various clinical applications, nasal delivery devices, and the scope and limitations of this approach.

Oxytocin: An Old Hormone, A Novel Psychotropic Drug And Possible Use In Treating Psychiatric Disorders

BACKGROUND

Oxytocin is a nonapeptide synthesized in the paraventricular and supraoptic nuclei of the hypothalamus. Historically, this molecule has been involved as a key factor in the formation of infant attachment, maternal behavior and pair bonding and, more generally, in linking social signals with cognition, behaviors and reward. In the last decades, the whole oxytocin system has gained a growing interest as it was proposed to be implicated in etiopathogenesis of several neurodevelopmental and neuropsychiatric disorders.

METHODS

With the main goal of an in-depth understanding of the oxytocin role in the regulation of different functions and complex behaviors as well as its intriguing implications in different neuropsychiatric disorders, we performed a critical review of the current state of art. We carried out this work through PubMed database up to June 2021 with the search terms: 1) "oxytocin and neuropsychiatric disorders"; 2) "oxytocin and neurodevelopmental disorders"; 3) "oxytocin and anorexia"; 4) "oxytocin and eating disorders"; 5) "oxytocin and obsessive-compulsive disorder"; 6) "oxytocin and schizophrenia"; 7) "oxytocin and depression"; 8) "oxytocin and bipolar disorder"; 9) "oxytocin and psychosis"; 10) "oxytocin and anxiety"; 11) "oxytocin and personality disorder"; 12) "oxytocin and PTSD".

RESULTS

Biological, genetic, and epigenetic studies highlighted quality and quantity modifications in the expression of oxytocin peptide or in oxytocin receptor isoforms. These alterations would seem to be correlated with a higher risk of presenting several neuropsychiatric disorders belonging to different psychopathological spectra. Collaterally, the exogenous oxytocin administration has shown to ameliorate many neuropsychiatric clinical conditions.

CONCLUSION

Finally, we briefly analyzed the potential pharmacological use of oxytocin in patient with severe symptomatic SARS-CoV-2 infection due to its anti-inflammatory, anti-oxidative and immunoregulatory properties.

Utility of Downstream Biomarkers to Assess and Optimize Intranasal Delivery of Oxytocin

Oxytocin (OT), a mammalian neurohormone associated with social cognition and behavior, can be administered in its synthetic form intranasally (IN) and impact brain chemistry and behavior. IN-OT shows potential as a noninvasive intervention for disorders characterized by social challenges, e.g., autism spectrum disorder (ASD) and anorexia nervosa (AN). To evaluate IN-OT’s efficacy, we must quantify OT uptake, availability, and clearance; thus, we assessed OT levels in urine (uOT) before and after participants (26 ASD, 7 AN, and 7 healthy controls) received 40 IU IN-OT or placebo across two sessions using double-blind, placebo-controlled crossover designs. We also measured uOT and plasma (pOT) levels in a subset of participants to compare the two sampling methods. We found significantly higher uOT and pOT following intranasal delivery of active compound versus placebo, but analyses yielded larger effect sizes and more clearly differentiated pre–post-OT levels for uOT than pOT. Further, we applied a two-step cluster (TSC), blinded backward-chaining approach to determine whether active/placebo groups could be identified by uOT and pOT change alone; uOT levels may serve as an accessible and accurate systemic biomarker for OT dose–response. Future studies will explore whether uOT levels correlate directly with behavioral targets to improve dosing for therapeutic goals.

Oxytocin Receptor-Expressing Neurons in the Paraventricular Thalamus Regulate Feeding Motivation through Excitatory Projections to the Nucleus Accumbens Core

Oxytocin receptors (OTR) have been found in the paraventricular thalamus (PVT) for the regulation of feeding and maternal behaviors. However, the functional projections of OTR-expressing PVT neurons remain largely unknown. Here, we used chemogenetic and optogenetic tools to test the role of OTR-expressing PVT neurons and their projections in the regulation of food intake in both male and female OTR-Cre mice. We found chemogenetic activation of OTR-expressing PVT neurons promoted food seeking under trials with a progressive ratio schedule of reinforcement. Using Feeding Experimentation Devices for real-time meal measurements, we found chemogenetic activation of OTR-expressing PVT neurons increased meal frequency but not cumulative food intake because of a compensatory decrease in meal sizes. In combination with anterograde neural tracing and slice patch-clamp recordings, we found optogenetic stimulation of PVT OTR terminals excited neurons in the posterior basolateral amygdala (pBLA) and nucleus accumbens core (NAcC) as well as local PVT neurons through monosynaptic glutamatergic transmissions. Photostimulation of OTR-expressing PVT-NAcC projections promoted food-seeking, whereas selective activation of PVT-pBLA projections produced little effect on feeding. In contrast to selective activation of OTR terminals, photostimulation of a broader population of glutamatergic PVT terminals exerted direct excitation followed by indirect lateral inhibition on neurons in both NAcC and anterior basolateral amygdala. Together, these results suggest that OTR-expressing PVT neurons are a distinct population of PVT glutamate neurons that regulate feeding motivation through projections to NAcC.SIGNIFICANCE STATEMENT The paraventricular thalamus plays an important role in the regulation of feeding motivation. However, because of the diversity of paraventricular thalamic neurons, the specific neuron types promoting food motivation remain elusive. In this study, we provide evidence that oxytocin receptor-expressing neurons are a specific group of glutamate neurons that primarily project to the nucleus accumbens core and posterior amygdala. We found that activation of these neurons promotes the motivation for food reward and increases meal frequency through projections to the nucleus accumbens core but not the posterior amygdala. As a result, we postulate that oxytocin receptor-expressing neurons in the paraventricular thalamus and their projections to the nucleus accumbens core mainly regulate feeding motivation but not food consumption.

Oxytocin in Women's Health and Disease

Oxytocin (OT) is a nonapeptide mainly produced in the supraoptic and paraventricular nuclei. OT in the brain and blood has extensive functions in both mental and physical activities. These functions are mediated by OT receptors (OTRs) that are distributed in a broad spectrum of tissues with dramatic sexual dimorphism. In both sexes, OT generally facilitates social cognition and behaviors, facilitates parental behavior and sexual activity and inhibits feeding and pain perception. However, there are significant differences in OT levels and distribution of OTRs in men from women. Thus, many OT functions in men are different from women, particularly in the reproduction. In men, the reproductive functions are relatively simple. In women, the reproductive functions involve menstrual cycle, pregnancy, parturition, lactation, and menopause. These functions make OT regulation of women's health and disease a unique topic of physiological and pathological studies. In menstruation, pre-ovulatory increase in OT secretion in the hypothalamus and the ovary can promote the secretion of gonadotropin-releasing hormone and facilitate ovulation. During pregnancy, increased OT synthesis and preterm release endow OT system the ability to promote maternal behavior and lactation. In parturition, cervix expansion-elicited pulse OT secretion and uterine OT release accelerate the expelling of fetus and reduce postpartum hemorrhage. During lactation, intermittent pulsatile OT secretion is necessary for the milk-ejection reflex and maternal behavior. Disorders in OT secretion can account for maternal depression and hypogalactia. In menopause, the reduction of OT secretion accounts for many menopausal symptoms and diseases. These issues are reviewed in this work.

Neural Functions of Hypothalamic Oxytocin and its Regulation

Oxytocin (OT), a nonapeptide, has a variety of functions. Despite extensive studies on OT over past decades, our understanding of its neural functions and their regulation remains incomplete. OT is mainly produced in OT neurons in the supraoptic nucleus (SON), paraventricular nucleus (PVN) and accessory nuclei between the SON and PVN. OT exerts neuromodulatory effects in the brain and spinal cord. While magnocellular OT neurons in the SON and PVN mainly innervate the pituitary and forebrain regions, and parvocellular OT neurons in the PVN innervate brainstem and spinal cord, the two sets of OT neurons have close interactions histologically and functionally. OT expression occurs at early life to promote mental and physical development, while its subsequent decrease in expression in later life stage accompanies aging and diseases. Adaptive changes in this OT system, however, take place under different conditions and upon the maturation of OT release machinery. OT can modulate social recognition and behaviors, learning and memory, emotion, reward, and other higher brain functions. OT also regulates eating and drinking, sleep and wakefulness, nociception and analgesia, sexual behavior, parturition, lactation and other instinctive behaviors. OT regulates the autonomic nervous system, and somatic and specialized senses. Notably, OT can have different modulatory effects on the same function under different conditions. Such divergence may derive from different neural connections, OT receptor gene dimorphism and methylation, and complex interactions with other hormones. In this review, brain functions of OT and their underlying neural mechanisms as well as the perspectives of their clinical usage are presented.

Discussions and perspectives regarding oxytocin as a biomarker in human investigations

This article introduces a review of research that has implemented oxytocin measurements in different fluids such as plasma, cerebrospinal fluid, urine and, mainly, saliva. The main purpose is to evaluate the level of evidence supporting the measurement of this biomarker implicated in a variety of psychological and social processes. First, a review of the technical developments that allowed the characterization, function establishing, and central and peripheral levels of this hormone is proposed. Then, the article approaches the current discussions regarding the level of reliability of the laboratory techniques that enable the measurement of oxytocin, focusing mainly on the determination of its concentration in saliva through Enzyme-Linked Immunosorbent Assay (ELISA). Finally, research results, which have established the major physiological correlates of this hormone in fields such as social neuroscience and neuropsychology, are collected and discussed in terms of the hormone measurement methods that different authors have used. In this way, the article is expected to contribute to the panorama of debates and current perspectives regarding investigation involving this important biomarker.

Effects of intranasal oxytocin in food intake and craving: A meta-analysis of clinical trials

OBJECTIVE

A rise of endogenous oxytocin (OT) is associated with anxiety and meal size reduction, and the effects of intranasal OT (INOT) have been examined in the management of food intake and craving. However, the discrepancy INOT effects in different disease populations are not entirely clear.

RESEARCH DESIGN AND METHODS

Updated systematic review and meta-analysis. By systematically searching the PubMed, Embase and Cochrane Library, we obtained 12 controlled trials. We performed meta-analyses to examine food intake, craving, anxiety or stress reduction on INOT administration, using standard mean difference (SMD) with a 95% confidence interval (CI) and a random-effects model.

RESULTS

This study examined 12 trials with 266 non-psychiatric and 157 psychiatric participants. The pooled results showed that single-dose INOT induced a significant lesser food intake in non-psychiatric subjects (SMD: -0.66 [95% CI: -1.18, -0.14]), but no effects was found in anorexia nervosa (AN) (SMD: 0.17 [95% CI: -0.32, 0.66]), bulimia nervosa (BN) and binge eating disorder (BED) (SMD: -0.41 [95% CI: -0.94, 0.11]), and schizophrenia (SMD: 0.04 [95% CI: -0.94, 1.02] subjects. Further analysis on leisure food also indicated an inhibition of consumption of chocolate biscuits in non-psychiatric subjects. Neither the non-psychiatric (SMD: -0.08 [95% CI: -0.50, 0.33]) nor the BN and BED (SMD: -0.08 [95% CI: -0.72, 0.88]) and schizophrenia subjects (SMD: -0.07 [95% CI: -1.05, 0.91]) demonstrated a difference in food craving or hunger compared with placebo. Anxiety or stress level was not influenced by INOT in any subgroup (non-psychiatric, SMD: 0.19 [95% CI: -0.22, 0.60]; AN, SMD: -0.01 [95% CI: -0.28, 0.88]; BN and BED: SMD: 0.00 [95% CI: -0.80, 0.80]).

CONCLUSIONS

Single-dose INOT significantly reduces food intake in nonpsychiatric subjects, and further studies are necessary to assess the long-term effects and safety in obese patients. Whether INOT could be a treatment option for patients with eating disorders remains to be investigated.

Associations between oxytocin and empathy in humans: A systematic literature review

This is a systematic review about the association between empathic behavior and oxytocin (OXT). Searches were conducted in the electronic databases PubMed, Web of Science, PsycINFO, SciELO, and LILACS using the search terms "oxytocin", "empathy", and "empathic". Forty-four studies were reviewed. Scarce findings point to a lack of association between baseline endogenous OXT levels and empathy traits, and for a trend towards a direct relationship between oxytocinergic reactivity and empathic functioning. The results showed that variations in empathy were related to polymorphisms in the OXT receptor gene, especially in rs53576, and that this relationship seems to mediated by individual, ethnic, and cultural characteristics. Most studies on the exogenous administration of OXT tested a single dose (24 IU) with positive effects mainly on the affective domain of empathy. At the neural level, findings were inconsistent. Taken together, the results of the studies reviewed support the existence of a relationship between OXT and empathy that is complex and multifaceted. Robust evidence is still needed to elucidate existing links. Future investigations could benefit from methodological improvements aimed at increasing the reproducibility and applicability of findings, as well as the systematic assessment of the effects of exogenous OXT considering dose and frequency of administration, genotyping, and hormonal availability at the peripheral and central levels. This should lead to significant progress in the understanding of the therapeutic possibilities of OXT in the domain of empathic behavior.

Oxytocin activation of paraventricular thalamic neurons promotes feeding motivation to attenuate stress-induced hypophagia

The neuropeptide oxytocin (OT) regulates important brain functions including feeding through activating OT receptors in multiple brain areas. Both OT fibers and OT receptors have been reported in the paraventricular thalamus (PVT), an area that was revealed to be important for the control of emotion, motivation, and food intake. However, the function and modulation of PVT OT signaling remain unknown. Here, we used a progressive ratio (PR) schedule of reinforcement to examine the role of PVT OT signaling in regulating the motivation for food and patch-clamp electrophysiology to study the modulation of OT on PVT neurons in brain slices. We demonstrate that PVT OT administration increases active lever presses to earn food rewards in both male and female mice under PR trials and OT receptor antagonist atosiban inhibits OT-induced increase in motivated lever presses. However, intra-PVT OT infusion does not affect food intake in normal conditions but attenuates hypophagia induced by stress and anxiety. Using patch-clamp recordings, we find OT induces long-lasting excitatory effects on neurons in all PVT regions, especially the middle to posterior PVT. OT not only evokes tonic inward currents but also increases the frequency of spontaneous excitatory postsynaptic currents on PVT neurons. The excitatory effect of OT on PVT neurons is mimicked by the specific OT receptor agonist [Thr4, Gly7]-oxytocin (TGOT) and blocked by OT receptor antagonist atosiban. Together, our study reveals a critical role of PVT OT signaling in promoting feeding motivation to attenuate stress-induced hypophagia through exciting PVT neurons.

Is Serum BDNF Altered in Acute, Short- and Long-Term Recovered Restrictive Type Anorexia Nervosa?

Brain-derived neurotrophic factor (BDNF), a neurotrophin involved in the regulation of food intake and body weight, has been implicated in the development and maintenance of Anorexia nervosa (AN). The majority of previous studies reported lower BDNF levels in acutely underweight AN patients (acAN) and increasing levels after weight rehabilitation. Here, we investigated serum BDNF concentrations in the largest known AN sample to date, both before and after weight restoration therapy. Serum BDNF was measured in 259 female volunteers: 77 in-patient acAN participants of the restrictive type (47 reassessed after short-term weight rehabilitation), 62 individuals long-term recovered from AN, and 120 healthy controls. We validated our findings in a post-hoc mega-analysis in which we reanalyzed combined data from the current sample and those from our previous study on BDNF in AN (combined sample: 389 participants). All analyses carefully accounted for known determinants of BDNF (age, sex, storage time of blood samples). We further assessed relationships with relevant clinical variables (body-mass-index, physical activity, symptoms). Contrary to our hypotheses, we found zero significant differences in either cross-sectional or longitudinal comparisons and no significant relationships with clinical variables. Together, our study suggests that BDNF may not be a reliable state- or trait-marker in AN after all.

Adolescents With Autism Spectrum Disorder and Anorexia Nervosa Comorbidity: Common Features and Treatment Possibilities With Cognitive Remediation Therapy and Oxytocin

Autistic traits or autism spectrum disorder (ASD) can be found in 4% to 52% of anorexic patients, which makes the treatment of these patients very challenging. In this review, possible ways to treat ASD and anorexia nervosa (AN) comorbidity in children and adolescents are summarized. Over recent years, the focus has shifted from searching for the evidence of connections between these two disorders, which have started with Gillberg's study in 1983, to searching for more effective and holistic treatment of this comorbidity. The latter is known to contribute to more severe courses and worse prognosis, which is probably related to the obstacles in both diagnosing and treating. Since AN usually starts in early adolescence and high-functioning ASD children seem to begin struggling with increased pressure in adolescence, while various comorbidities can occur, it is important to improve the treatment of this comorbidity in young patients and to tailor it specifically in terms of diagnosing. In this paper, a literature review is conducted on common features and promising treatment possibilities. We describe cognitive remediation therapy and the promising pharmacotherapeutic candidate oxytocin with a special focus on adolescents.

Potential shortcomings in current studies on the effect of intranasal oxytocin in Anorexia Nervosa and healthy controls - A systematic review and meta-analysis

RATIONALE

The psychopathology of anorexia nervosa (AN) includes altered social cognition and information processing of fear and anxiety. Oxytocin, a neuromodulating hormone, may influence these functions and could be valuable for the treatment of AN.

OBJECTIVE

The current study aimed at reviewing the effect of intranasal oxytocin (IN-OT) on attentional bias (AB) and emotion recognition (ER) in AN.

METHODS

A systematic literature review was done for free-text and the MeSH-terms: anorexia nervosa, feeding and eating disorders, and oxytocin. Six publications, reporting from 4 unique clinical trials, were included in this review. A meta-analysis was conducted to examine the effects of IN-OT on AB towards food images and ER on healthy controls (HC) and patients with AN.

RESULTS

Overall, IN-OT did not influence AB towards food images (effect size = 0.20 [- 0.16, 0.57], p = 0.28) and had no effect on ER (effect size = - 0.01 [- 0.27, 0.26], p = 0.97) in patients with AN and healthy control (HC) subjects collectively. Assessing HC and AN separately in subgroup analyses did not show any significant effect on AB and ER in neither of the subgroups. All tests were done between 15 and 55 min post-administration of IN-OT, while peak concentration in the cerebrospinal fluid has been determined to be at 75 min.

CONCLUSION

The current level of evidence is moderate showing no effect of IN-OT on AB or ER in AN. However, brain exposure may not have been sufficient which future studies with IN-OT need to ensure by considering dose and dose-to-task interval.

A pilot study investigating the influence of oxytocin on attentional bias to food images in women with bulimia nervosa or binge eating disorder

BACKGROUND

Previous research has found that exogenous oxytocin administration has the potential to modulate attentional biases in women with anorexia nervosa. Recent work has indicated that attentional biases to food may reinforce the recurrent binge eating behaviour characterising bulimia nervosa and binge eating disorder. To date, however, no study has yet investigated the effect of oxytocin on attentional biases to palatable food in women with bulimia nervosa and binge eating disorder.

METHODS

The present study employed a single-session cross-over design to test the hypothesis that a divided dose of 64 IU of intranasal oxytocin, administered as one intranasal dose of 40 IU of oxytocin followed by a top-up of 24 IU of oxytocin 80 minutes later, vs placebo administration administered in the same dosing schedule would reduce attentional biases towards food images in a dot probe task. We hypothesised that oxytocin administration would reduce vigilance towards food to a greater degree in women with bulimia nervosa or binge eating disorder vs healthy comparison women. Twenty-five women with bulimia nervosa or binge eating disorder and 27 comparison women without history of an eating disorder were recruited to take part in the study.

RESULTS

In contrast to our hypothesis, there was no main effect of diagnosis on attentional bias to food (fixed effect = 5.70, P = 0.363), nor a significant interaction between diagnosis and drug condition (fixed effect =-14.80, P = 0.645). There was a main effect of drug condition, such that oxytocin increased vigilance towards food vs neutral images in the dot probe task (fixed effect = 10.42, P = 0.044). A correlation analysis revealed that this effect was moderated by attentional bias in the placebo condition, such that greater avoidance of food stimuli in the placebo condition was associated with a greater increase in vigilance induced by oxytocin.

CONCLUSIONS

The findings of the present study add to a mixed body of literature investigating the therapeutic effects of oxytocin in women. Future research would benefit from dose-response studies investigating the optimal dose of oxytocin for modulating the attentional processing of palatable food in populations with eating disorders.

Pharmacotherapeutic strategies for the treatment of anorexia nervosa - too much for one drug?

INTRODUCTION

Anorexia nervosa is a severe psychiatric illness and no medication has been approved for its treatment. This lack of biological treatments requires the development of new directions for pharmacological research.

AREAS COVERED

There is modest but emerging evidence that dopamine D2 and serotonin 1A and 2A receptor agonistic and antagonist medication might be beneficial for weight gain, although the underlying mechanisms are uncertain. Improving quality of life including treating comorbid conditions is an additional important outcome measure, but this has not been well researched. Biological and psychological risk factors together with neurobiological alterations during the illness maintain the disorder 's pathophysiology. Neuroscience research can be used to understand those interactions and advance the research agenda. The authors discuss the above as well as give perspectives on future research.

EXPERT OPINION

If a multidisciplinary approach that includes evidence-based psychotherapy shows unsatisfactory success in weight normalization and cognitive-emotional recovery, then more experimental treatments that are safe and have indicated treatment effectiveness should be tried to augment treatment. Identification and treatment of comorbid conditions to improve quality of life of the patient should also be part of the treatment regimen, even if the effect on weight gain is uncertain.

Potential for limited reinforcing and abuse-related subjective effects of intranasal oxytocin

BACKGROUND

There has been growing interest in using oxytocin as a pharmacotherapy for psychiatric disorders, including substance use disorder. Limited data exist regarding oxytocin's reinforcing efficacy, which is a necessary consideration for novel pharmacotherapies, especially in substance-using populations.

AIMS

This study aimed to determine the potential reinforcing effects of intranasally administered oxytocin by assessing behavioral economic demand and subjective effects.

METHODS

Healthy adults (n = 23) participated in a double-blind, repeated-measures, laboratory study wherein they received intranasal oxytocin (40 IU) or placebo in a randomized order across two sessions. Participants completed drug purchasing tasks at the conclusion of both sessions. Throughout both sessions, subjective and physiological effects were assessed.

RESULTS

Demand-curve analysis of purchasing tasks revealed greater median purchasing for oxytocin relative to placebo. Physiological and subjective effects did not significantly differ between oxytocin and placebo. However, a nonsignificant trend was observed for moderately greater drug liking for oxytocin relative to placebo. There was a significant, positive correlation between the difference in drug liking (between oxytocin and placebo) and the difference in lowest-price purchasing (between oxytocin and placebo).

CONCLUSIONS

These data suggest the potential for limited reinforcing and abuse-related subjective effects of intranasal oxytocin. Given the small sample, the greater drug liking of oxytocin compared to placebo, and the positive relation between demand and drug liking, it is possible that oxytocin may produce reinforcing effects in some participants. Therefore, additional studies of oxytocin reinforcement are warranted.

A Preliminary Examination of Endogenous Peripheral Oxytocin in a Pilot Randomized Clinical Trial of Oxytocin-Enhanced Psychotherapy for Posttraumatic Stress Disorder

BACKGROUND

Preclinical and clinical research suggests that the oxytocin system is implicated in the development and maintenance of stress and anxiety-related psychiatric conditions, such as posttraumatic stress disorder (PTSD). Recent research also suggests that intranasal oxytocin holds promise as a treatment for PTSD. However, little is known about the relationship between levels of peripheral oxytocin and PTSD symptom severity, PTSD treatment response, and repeated intranasal oxytocin administration.

METHODS

In the current study, we examined associations between PTSD symptom severity and peripheral oxytocin levels measured in plasma before and after a course of prolonged exposure (PE) for PTSD (n = 13); participants were randomized to adjunctive intranasal oxytocin (n = 6) or placebo (n = 7).

RESULTS

Baseline peripheral oxytocin levels were not associated with baseline PTSD symptom severity. Change in peripheral oxytocin levels did not differ by treatment condition and did not correspond to change in PTSD symptoms.

CONCLUSIONS

This proof-of-concept study illustrates the acceptability and feasibility of measuring peripheral oxytocin among individuals engaged in psychotherapy for PTSD and informs the utilization of these procedures in future adequately powered studies.

Eating disorder animal model

PURPOSE OF REVIEW

The aim of this review is to describe animal models that simulate the features of eating disorders. The literature pertaining to animal models that are of relevance for clinical eating disorders and the possible underpinning mechanisms was reviewed using PubMed, Ovid database and Google Scholar.

RECENT FINDINGS

New refinements of the circuits regulated by neurotransmitters and neuropeptides which instigate eating behaviours and the various feedback pathways which monitor acute and chronic nutrient status continue to be discovered. Moreover, work with the animal models that simulate the behavioural features and risk factors related to eating disorders is flourishing and providing new insights into possible causal mechanisms. For example, rodents develop binge-eating behaviours if they are intermittently exposed to processed, palatable foods and/or sugar adulterated drinks. This led to the controversial conceptualization of binge eating as a form of food addiction. Self-starvation taken to a fatal consequence such as occurs in anorexia nervosa can emerge in rodents exposed to triggers like social exclusion and/or the opportunity to exercise.

SUMMARY

There are plausible animal models for both anorexia nervosa and binge-eating disorders. These can be used to elaborate the theoretical models to explain the mechanisms underpinning eating disorders.

The influence of oxytocin on eating behaviours and stress in women with bulimia nervosa and binge eating disorder

The current study aimed to test the influence of oxytocin on palatable food intake, 24-h caloric consumption, and stress in women with bulimia nervosa and binge eating disorder. We recruited 25 women with DSM-5 bulimia nervosa or binge eating disorder, and 27 weight-matched comparison women without history of an eating disorder. We employed a double-blind, placebo-controlled crossover design in which each participant attended the lab for two experimental sessions, receiving a divided dose of 64IU intranasal oxytocin in one session and equivalent volume of placebo nasal spray in the opposite session. The order of administration was pseudo-randomised across participants. We hypothesised that a divided dose of 64IU intranasal oxytocin administration would reduce subjective hunger, the immediate consumption of palatable food, 24-h calorie consumption, and the incidence of binge eating when compared to placebo. We also hypothesised that oxytocin administration would be associated with lower levels of stress and salivary cortisol, and that there would be an interaction with participant group such that oxytocin would reduce eating behaviour and stress to a greater degree in women with bulimia nervosa or binge eating disorder, compared to women without history of an eating disorder. We did not find a significant effect of oxytocin on any of the measurements of eating behaviour, subjective stress, or salivary cortisol. We recommend that future studies test the dose-response effect of oxytocin on eating behaviours and stress in human populations with eating disorders to further clarify the moderating factors for oxytocin's effect on eating.

Chronic oxytocin administration as a tool for investigation and treatment: A cross-disciplinary systematic review

Oxytocin (OT) subserves various physiological, behavioral, and cognitive processes. This paired with the ability to administer OT with minimal and inconsistent side effects has spurred research to explore its therapeutic potential. Findings from single-dose studies indicate that OT administration may be beneficial, at least under certain circumstances. The state of the field, however, is less clear regarding effects from chronic OT administration, which more closely resembles long-term treatment. To address this gap, this review synthesizes existing findings on the use of chronic OT administration in animal and human work. In addition to detailing the effects of chronic OT administration across different functional domains, this review highlights factors that have contributed to mixed findings. Based on this review, a basic framework of interrelated regulatory functions sensitive to chronic OT administration is offered. The paper also identifies future research directions across different contexts, populations, and outcomes, specifically calling for more systematic and standardized research on chronic OT administration in humans to supplement and expand what is currently known from preclinical work.

Interaction between polymorphisms of the oxytocinergic system genes and emotion perception in inpatients with anorexia nervosa

OBJECTIVE

The empirical literature describes the role of the oxytocinergic system in emotion perception (EP). Variants in the oxytocin (OXT) and oxytocin receptor genes have been associated with mental disorders, including anorexia nervosa (AN), that are characterized by difficulties in socioemotional functioning. Our study aimed to examine whether variability within the genes related to OXT pathways may play a role in facial EP in inpatients with AN.

METHOD

Single nucleotide polymorphisms (SNPs) of the following genes: oxytocin receptor (rs2254298, rs53576), OXT (rs6133010), OXT-arginine-vasopressin (rs2740204), CD38 (rs6449197, rs3796863), and human leucyl/cystinylaminopeptidase (rs4869317) were genotyped in 60 AN female inpatients and 60 healthy control females (HCs). Associations between genetic polymorphisms and EP as well as clinical symptoms were examined.

RESULTS

The AN group showed decreased EP abilities compared with HCs. SNPs of rs2740204, rs6133010, and rs53576 were associated with differences in EP in women with AN and in HCs. The SNP of rs4869317 was associated with the level of eating disorders symptoms in HCs.

CONCLUSIONS

The OXT system may be involved in EP difficulties in AN. SNPs within genes related to OXT pathways may influence EP abilities. The leucyl/cystinylaminopeptidase rs4869317 SNP may be involved in the development of eating disorders psychopathology.

Harm minimization in severe and enduring anorexia nervosa

For many sufferers of anorexia nervosa, the time course is long, and the prospect of disability and family burden great. This is all too often the case, even with early diagnosis and treatment. The term severe and enduring anorexia nervosa has been applied to these survivors. Yet, a majority of patients do eventually recover and, even where this is not the case, adaptive medical stability and function can be maintained despite alarming dilapidation. Managing the years of illness so as to have the best outcome physically and psychologically, even where full weight recovery does not occur, or has not yet occurred, is the topic of this article. Literature pertaining to harm minimization in chronic, severe, enduring, and long-standing anorexia nervosa was selectively reviewed using an Ovid data base and Google Scholar. The authors' own clinical experience over almost four decades in public and private hospital and community settings has also informed much of what has been written. The authors would like to think that it is possible to do better than the familiar injunction (variously attributed to Hippocrates, Galen, and others) of 'primum non nocere'-although this is a good place to start.

The effect of intranasal oxytocin on the perception of affective touch and multisensory integration in anorexia nervosa: protocol for a double-blind placebo-controlled crossover study

INTRODUCTION

Anorexia nervosa (AN) is an eating disorder characterised by restriction of energy intake, fears of gaining weight and related body image disturbances. The oxytocinergic system has been proposed as a pathophysiological candidate for AN. Oxytocin is a neuropeptide involved in bodily processes (eg, breast feeding) and in the onset of social behaviours (eg, bonding). Studies investigating the effect of intranasal oxytocin (IN-OT) in AN showed that it can improve attentional bias for high-calorie food and fat bodies stimuli, and related stress. However, less is known about the effect of IN-OT on bodily awareness and body image distortions, key features of the disorder linked to its development, prognosis and maintenance. Here, we aim to investigate the effect of IN-OT on the perception of affective, C-tactile-optimal touch, known to be impaired in AN and on multisensory integration processes underlying a body ownership illusion (ie, rubber hand illusion). For exploratory purposes, we will also investigate the effect of IN-OT on another interoceptive modality, namely cardiac awareness and its relationship with affective touch.

DESIGN, METHODS AND ANALYSIS

Forty women with AN and forty matched healthy controls will be recruited and tested in two separate sessions; self-administering IN-OT (40 IU) or placebo, intranasally, in a pseudo-randomised manner. The data from this double-blind, placebo-controlled, cross-over study will be analysed using linear mixed models that allow the use of both fixed (treatment levels) and random (subjects) effects in the same analysis. To address our main hypotheses, separate analyses will be run for the affective touch task, where the primary outcome dependent variable will be the pleasantness of the touch, and for the rubber hand illusion, where we will investigate multisensory integration quantified as subjective embodiment towards the rubber hand. In the latter, we will manipulate the synchronicity of touch and the size of the hand.

ETHICS AND DISSEMINATION

Ethics approval has been obtained by National Research Ethics Service NRES Committee London (Queen's Square Committee, ref number 14/LO/1593). The results will be disseminated through conference presentations and publication in peer-reviewed journals.

Treatment outcomes for anorexia nervosa: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

To determine the impact of specialized treatments, relative to comparator treatments, upon the weight and psychological symptoms of anorexia nervosa (AN) at end-of-treatment (EOT) and follow-up.

METHODS

Randomized controlled trials (RCTs) between January 1980 and December 2017 that reported the effects of at least two treatments on AN were screened. Weight and psychological symptoms were analyzed separately for each study. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed, and studies were assessed using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) criteria and Cochrane risk of bias tool.

RESULTS

We identified 35 eligible RCTs, comprising data from 2524 patients. Meta-analyses revealed a significant treatment effect on weight outcomes at EOT [g = 0.16, 95% CI (0.05-0.28), p = 0.006], but not at follow-up [g = 0.11, 95% CI (-0.04 to 0.27), p = 0.15]. There was no significant treatment effect on psychological outcomes at either EOT [g = -0.03, 95% CI (-0.14 to 0.08), p = 0.63], or follow-up [g = -0.001, 95% CI (-0.11 to 0.11), p = 0.98]. There was no strong evidence of publication bias or significant moderator effects for illness duration, mean age, year of publication, comparator group category, or risk of bias (all p values &gt; 0.05).

CONCLUSIONS

Current specialized treatments are more adept than comparator interventions at imparting change in weight-based AN symptoms at EOT, but not at follow-up. Specialized treatments confer no advantage over comparator interventions in terms of psychological symptoms. Future precision treatment efforts require a specific focus on the psychological symptoms of AN.

Role of oxytocin in the control of stress and food intake

Oxytocin neurones in the hypothalamus are activated by stressful stimuli and food intake. The oxytocin receptor is located in various brain regions, including the sensory information-processing cerebral cortex; the cognitive information-processing prefrontal cortex; reward-related regions such as the ventral tegmental areas, nucleus accumbens and raphe nucleus; stress-related areas such as the amygdala, hippocampus, ventrolateral part of the ventromedial hypothalamus and ventrolateral periaqueductal gray; homeostasis-controlling hypothalamus; and the dorsal motor complex controlling intestinal functions. Oxytocin affects behavioural and neuroendocrine stress responses and terminates food intake by acting on the metabolic or nutritional homeostasis system, modulating emotional processing, reducing reward values of food intake, and facilitating sensory and cognitive processing via multiple brain regions. Oxytocin also plays a role in interactive actions between stress and food intake and contributes to adaptive active coping behaviours.

Medication in AN: A Multidisciplinary Overview of Meta-Analyses and Systematic Reviews

Drugs are widely prescribed for anorexia nervosa in the nutritional, somatic, and psychiatric fields. There is no systematic overview in the literature, which simultaneously covers all these types of medication. The main aims of this paper are (1) to offer clinicians an overview of the evidence-based data in the literature concerning the medication (psychotropic drugs and medication for somatic and nutritional complications) in the field of anorexia nervosa since the 1960s, (2) to draw practical conclusions for everyday practise and future research. Searches were performed on three online databases, namely MEDLINE, Epistemonikos and Web of Science. Papers published between September 2011 and January 2019 were considered. Evidence-based data were identified from meta-analyses, if there were none, from systematic reviews, and otherwise from trials (randomized or if not open-label studies). Evidence-based results are scarce. No psychotropic medication has proved efficacious in terms of weight gain, and there is only weak data suggesting it can alleviate certain psychiatric symptoms. Concerning nutritional and somatic conditions, while there is no specific, approved medication, it seems essential not to neglect the interest of innovative therapeutic strategies to treat multi-organic comorbidities. In the final section we discuss how to use these medications in the overall approach to the treatment of anorexia nervosa.

Impact of Oxytocin on the neural correlates of fearful face processing in PTSD related to childhood Trauma

Background: Posttraumatic stress disorder (PTSD) related to exposure to abuse and neglect during childhood is associated with particularly severe and persistent deleterious outcomes. Amygdala hyperreactivity has been observed in childhood trauma survivors and implicated in symptoms of PTSD. Objective: The neuropeptide oxytocin holds promise as a potential treatment for PTSD due to its ability to attenuate amygdala response to threat cues. However, the effect of oxytocin on amygdala reactivity in individuals with childhood trauma-related PTSD has not been investigated. Method: We employed a double-blind, randomized, placebo-controlled crossover design to examine the effects of intranasal oxytocin (24 IU) versus placebo on amygdala reactivity to fearful faces among childhood-trauma exposed individuals with PTSD (n = 17) and without PTSD (control group; n = 16). Results: Region-of-interest based amygdala fMRI signal magnitude did not differ by group, drug, or group x drug interaction. Self-report of childhood trauma exposure severity was negatively associated with the oxytocin-related change in left amygdala response in the PTSD group, but not in the control group. Supplementary and exploratory whole-brain analyses conducted separately in each group revealed that left amygdala reactivity to fearful faces was absent on placebo but increased on oxytocin in the control group. The PTSD group showed right amygdala activation to fearful faces in both the oxytocin and placebo conditions, but the left amygdala response observed in the placebo condition was diminished on oxytocin. Conclusions: Findings extend the literature pertaining to the potential for oxytocin to attenuate neural correlates of PTSD to a childhood trauma-related PTSD sample.

Social anxiety in the eating disorders: a systematic review and meta-analysis

Social anxiety disorder is one of the most common comorbid conditions in eating disorders (EDs). The aim of the current review and meta-analysis is to provide a qualitative summary of what is known about social anxiety (SA) in EDs, as well as to compare levels of SA in those with EDs and healthy controls. Electronic databases were systematically searched for studies using self-report measures of SA in ED populations. In total, 38 studies were identified, 12 of which were included in the meta-analyses. For both anorexia nervosa (AN) and bulimia nervosa, there were significant differences between ED groups and HCs, with medium to large effect sizes. Findings from the qualitative review indicate that levels of SA are similar across the ED diagnoses, and SA improves with treatment in AN. In addition, high levels of SA are associated with more severe ED psychopathology, but not body mass index. These findings add to the wider literature on socio-emotional functioning in EDs, and may have implications for treatment strategies.

The Neuropeptide Hormone Oxytocin in Eating Disorders

PURPOSE OF REVIEW

The neurohormone oxytocin (OXT) impacts food intake as well as cognitive, emotional, and social functioning-all of which are central to eating disorder (ED) pathology across the weight spectrum. Here, we review findings on endogenous OXT levels and their relationship to ED pathology, the impact of exogenous OXT on mechanisms that drive ED presentation and chronicity, and the potential role of genetic predispositions in the OXT-ED link.

RECENT FINDINGS

Current findings suggest a role of the OXT system in the pathophysiology of anorexia nervosa. In individuals with bulimia nervosa, endogenous OXT levels were comparable to those of healthy controls, and exogenous OXT reduced food intake. Studies in other ED are lacking. However, genetic studies suggest a broad role of the OXT system in influencing ED pathology. Highlighting findings on why OXT represents a potential biomarker of and treatment target for ED, we advocate for a systematic research approach spanning the entire ED spectrum.

Premorbid and Illness-related Social Difficulties in Eating Disorders: An Overview of the Literature and Treatment Developments

BACKGROUND

Social difficulties in eating disorders can manifest as predisposing traits and premorbid difficulties, and/or as consequences of the illness.

OBJECTIVE

The aim of this paper is to briefly review the evidence of social problems in people with eating disorders and to consider the literature on treatments that target these features.

METHOD

A narrative review of the literature was conducted.

RESULTS

People with eating disorders often manifest traits, such as shyness, increased tendency to submissiveness and social comparison, and problems with peer relationships before illness onset. Further social difficulties occur as the illness develops, including impaired social cognition and increased threat sensitivity. All relationships with family, peers and therapists are compromised by these effects. Thus, social difficulties are both risk and maintaining factors of eating disorders and are suitable targets for interventions. Several forms of generic treatments (e.g. interpersonal psychotherapy, cognitive analytic therapy, focal psychodynamic therapy) have an interpersonal focus and show some efficacy. Guided self-management based on the cognitive interpersonal model of the illness directed to both individuals and support persons has been found to improve outcomes for all parties. Adjunctive treatments that focus on specific social difficulties, such as cognitive remediation and emotion skills training and cognitive bias modification have been shown to have a promising role.

CONCLUSION

More work is needed to establish whether these approaches can improve on the rather disappointing outcomes that are attained by currently used treatments for eating disorders.