Treatment of Eating Disorders can not Remain ‘Brainless’: The Case for Brain-Directed Treatments

Assessing midbrain neuromelanin and its relationship to reward learning in anorexia nervosa: Stage 1 of a registered report

INTRODUCTION

Anorexia nervosa (AN) is a debilitating and potentially chronic eating disorder, characterized by low hedonic drive toward food, which has been linked with perturbations in both reward processing and dopaminergic activity. Neuromelanin-sensitive magnetic resonance imaging (MRI) is an emerging method to index midbrain neuromelanin-a by-product of dopaminergic synthesis. The assessment of midbrain neuromelanin, and its association with AN psychopathology and reward-related processes, may provide critical insights into reward circuit function in AN.

METHODS

This study will incorporate neuromelanin-sensitive MRI into an existing study of appetitive conditioning in those with AN. Specifically, those with acute and underweight AN (N = 30), those with weight-restored AN (N = 30), and age-matched healthy controls (N = 30) will undergo clinical assessment of current and previous psychopathology, in addition to structural neuromelanin-sensitive MRI, diffusion MRI, and functional MRI (fMRI) during appetitive conditioning.

CONCLUSION

This study will be among the first to interrogate midbrain neuromelanin in AN-a disorder characterized by altered dopaminergic activity. Results will help establish whether abnormalities in the midbrain synthesis of dopamine are evident in those with AN and are associated with symptomatic behavior and reduced ability to experience pleasure and reward.

Strategic avoidance of food stimuli in patients with restrictive anorexia nervosa: An eye-tracking evaluation

OBJECTIVE

A biased attentional processing of food stimuli may represent a disorder maintenance factor in patients with anorexia nervosa (AN). The present study aimed at investigating the temporal course of attentional deployment towards both high-calorie and low-calorie foods in patients with AN using eye-tracking.

METHOD

Fifty-two patients with restrictive AN and 54 healthy controls (HC) performed a dot-probe task while their gaze was recorded with an eye-tracking system. The direction bias (percentage of trials in which the gaze was directed towards the food at first fixation, 500, and 1500 ms), and the duration bias (percentage of time spent looking at the food) were extracted.

RESULTS

Regarding the direction bias, a group by time interaction emerged (F = 3.29, p = 0.038): while in the control group the bias continued to increase over the course of the trial, patients with AN showed a reduction of the bias between the 500 and 1500 ms. No group differences were observed on the duration bias.

CONCLUSIONS

In advanced stages of attentional deployment patients with AN start to differ from HC by diverting their attention away from food stimuli, a strategic process that may contribute to food avoidance and calorie restriction.

Anodal stimulation of inhibitory control and craving in satiated restrained eaters

OBJECTIVES

Eating and weight disorders are severe and complex clinical conditions which, among other behaviors, include (attempts at) restrained eating, food avoidance, following dietary rules, and overeating. Comparable to women with obesity, restrained eaters (RE) without formal eating disorder diagnosis are worse at inhibiting their motor responses than unrestrained eaters (URE). According to neuroimaging studies, the right inferior frontal gyrus (rIFG) is involved in inhibitory control which, in turn, could be improved by neuromodulation such as anodal transcranial direct current stimulation (tDCS) across rIFG.

METHODS

This double-blind sham-controlled cross-over study was conducted after a standardized breakfast. Normal-weight female RE und URE performed a stop-signal task (SST) with food and non-food stimuli during sham or anodal tDCS. Food craving, hunger, and satiety were self-reported before and after tDCS. We employed a mixed between-subjects (group: RE vs. URE) and within-subjects factorial design (tDCS: anodal tDCS vs. sham; stimuli: food vs. control pictures).

RESULTS

Breakfast consumption was comparable for RE and URE, as well as craving, hunger, and thirst. Regarding inhibitory control, a significant two-way interaction between group and tDCS ermerged: RE had longer stop-signal reaction times (SSRTs) during sham tDCS, but they improved to the level of URE by application of anodal tDCS.

DISCUSSION

Results replicated an inhibitory control deficit in RE with longer SSRTs compared to URE without stimulation. During anodal tDCS to the rIFG, reduced SSRTs in RE indicated an improvement in inhibitory control. The findings suggest a specificity of rIFG stimulation in at-risk groups with regards to inhibitory control irrespective of craving.

Therapeutic uses of psychedelics for eating disorders and body dysmorphic disorder

BACKGROUND

Clinical use of psychedelics has gained considerable attention, with promising benefits across a range of mental disorders. Current pharmacological and psychotherapeutic treatments for body dysmorphic disorder (BDD) and eating disorders (EDs) have limited efficacy. As such, other treatment options such as psychedelic-assisted therapies are being explored in these clinical groups.

AIMS

This systematic review evaluates evidence related to the therapeutic potential of psychedelics in individuals diagnosed with BDD and EDs.

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we conducted a systematic review of all study designs published to the end of February 2022 that identified changes in ED/BDD symptom severity from psychedelics using validated measures to assess symptom changes.

RESULTS

Our search detected a total of 372 studies, of which five met inclusion criteria (two exploratory studies, two case reports, and one prospective study). These were included in the data evaluation. Effects of psychedelics on BDD and various ED symptoms were identified mostly through thematic analyses and self-reports.

CONCLUSIONS

Our findings highlight that more research is needed to determine the safety and efficacy of psychedelics in BDD and EDs and we suggest avenues for future exploration.

'My dad was like "it's your brain, what are you doing?"': Participant experiences of repetitive transcranial magnetic stimulation treatment in severe enduring anorexia nervosa

Objective

Repetitive transcranial magnetic stimulation (rTMS) is a promising emerging treatment for anorexia nervosa (AN). However, to date, patients' views and experiences of this treatment have not been fully explored. To assess these, we integrated a qualitative study into a feasibility randomised controlled trial of rTMS in individuals with severe enduring AN.

Method

Twenty‐nine (of 34) trial participants contributed to this study. Semi‐structured interviews were conducted 3‐months following the completion of rTMS treatment (4‐months post‐randomisation), prior to unblinding. Transcripts were analysed using content analysis.

Results

rTMS was deemed an acceptable but time‐consuming treatment. Many emphasised how their lives had changed to some extent during, but mainly after treatment by making them more positive, open‐minded, flexible and willing to try new things in relation to their AN and other aspects of their lives.

Conclusions

These qualitative data will be valuable in shaping participant information, recruitment and planning of future large‐scale trials of rTMS in AN.

Trial Registration

ISRCTN14329415, registered 23rd July 2015, https://www.isrctn.com/ISRCTN14329415

This study is the first to systematically explore participants' experiences of repetitive transcranial magnetic stimulation (rTMS) treatment for severe enduring anorexia nervosa (AN), as part of a randomised controlled feasibility trial.

Participants expressed that rTMS was an acceptable but time‐consuming treatment. Many participants who received real rTMS described positive changes in relation to AN and quality of life.

Findings from this qualitative study will help to shape future research of rTMS treatment for AN.

Neurosurgery and neuromodulation for anorexia nervosa in the 21st century: a systematic review of treatment outcomes

As current psychosocial and pharmacological interventions show limited efficacy in the treatment of anorexia nervosa (AN), interest in the potential value of neurosurgical intervention and neuromodulation in managing severe and enduring illness has grown. We conducted a systematic review of 20 trials of neurosurgical and neuromodulatory treatments for AN, including neurosurgical ablation, deep brain stimulation (DBS), repetitive transcranial magnetic stimulation (rTMS), and transcranial direct current stimulation (tDCS). Overall, there is evidence to support the role of stereotactic ablation and DBS in the treatment of AN. In contrast, results for rTMS and tDCS have been modest and generally more mixed. Neurosurgical treatment may offer important new avenues for the treatment of AN. Additional randomized clinical trials with comparable patient populations will be needed, in which change in affective, cognitive, and perceptual symptom phenomena, and interrogation of targeted circuits, pre- and post-intervention, are carefully documented.

Does concurrent self-administered transcranial direct current stimulation and attention bias modification training improve symptoms of binge eating disorder? Protocol for the TANDEM feasibility randomized controlled trial

BACKGROUND

Binge eating disorder (BED) is a common and disabling problem associated with impaired cognitive control. Preliminary studies show that brain-directed treatments, including transcranial direct current stimulation (tDCS) and attention bias modification training (ABMT), improve cognitive control and alleviate symptoms of BED. When combined, tDCS may enhance the effects of ABMT, and vice versa, thereby improving treatment outcomes.

METHODS

This protocol describes a feasibility single-blind randomized sham-controlled trial of concurrent self-administered tDCS and ABMT in adults with BED (The TANDEM Trial). Eighty adults with BED will be randomly assigned to one of four groups: ABMT with real or sham self-administered tDCS, ABMT only, or waiting list control. In the treatment arms, participants will complete 10-sessions of their allocated intervention over 2-3 weeks. Outcomes will be assessed at baseline (T0), immediately post treatment (T1), and 6 weeks after end of treatment (T2), and at comparable timepoints for participants in the waitlist control group. Feasibility will be evaluated by assessing recruitment/retention rates and blinding success. Acceptability will be assessed quantitatively via participant ratings and qualitatively via semi-structured interviews. Episodes of binge eating at follow-up will be the primary clinical outcome and rate ratios from Poisson regression will be reported. Secondary outcomes will assess changes in ED and general psychopathology, attention bias toward high calorie foods, and executive function.

DISCUSSION

It is hoped that data from the trial will contribute to the development of neurobiologically informed treatments for BED, provide insights into the potential use of at-home variants of tDCS, and inform the design of future large scale trials.

White matter tracts characteristics in habitual decision-making circuit underlie ritual behaviors in anorexia nervosa

Anorexia nervosa (AN) is a difficult to treat, pernicious psychiatric disorder that has been linked to decision-making abnormalities. We examined the structural characteristics of habitual and goal-directed decision-making circuits and their connecting white matter tracts in 32 AN and 43 healthy controls across two independent data sets of adults and adolescents as an explanatory sub-study. Total bilateral premotor/supplementary motor area-putamen tracts in the habit circuit had a significantly higher volume in adults with AN, relative to controls. Positive correlations were found between both the number of tracts and white matter volume (WMV) in the habit circuit, and the severity of ritualistic/compulsive behaviors in adults and adolescents with AN. Moreover, we found a significant influence of the habit circuit WMV on AN ritualistic/compulsive symptom severity, depending on the preoccupations symptom severity levels. These findings suggest that AN is associated with white matter plasticity alterations in the habit circuit. The association between characteristics of habit circuit white matter tracts and AN behavioral symptoms provides support for a circuit based neurobiological model of AN, and identifies the habit circuit as a focus for further investigation to aid in development of novel and more effective treatments based on brain-behavior relationships.

A pilot study exploring the effect of repetitive transcranial magnetic stimulation (rTMS) treatment on cerebral blood flow and its relation to clinical outcomes in severe enduring anorexia nervosa

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) is a novel treatment option for people with severe enduring anorexia nervosa (SE-AN), but associated neurobiological changes are poorly understood. This study investigated the effect of rTMS treatment on regional cerebral blood flow (CBF) and whether any observed changes in CBF are associated with changes in clinical outcomes in people with SE-AN.

METHODS

As part of a randomised sham-controlled feasibility trial of 20 sessions of high-frequency rTMS to the left dorsolateral prefrontal cortex, 26 of 34 trial participants completed arterial spin labelling (ASL) functional magnetic resonance imaging (fMRI) to quantify regional and global resting state CBF before (pre-randomisation baseline) and after real or sham treatment (1-month post-randomisation). A group of healthy females (n = 30) were recruited for baseline comparison. Clinical outcomes, including BMI, and depression and anxiety symptoms, were assessed at baseline, 1-, 4-, and 18-months post-randomisation.

RESULTS

No group differences in regional CBF were identified between the SE-AN and healthy comparison participants. A significant treatment-by-time interaction in a medial temporal lobe cluster with the maximal peak in the right amygdala was identified, reflecting a greater reduction in amygdala CBF following real rTMS compared to sham. Participants with the greatest rTMS-related reduction in amygdala CBF (i.e., between baseline and 1-month post-randomisation) showed the greatest sustained weight gain at 18-months post-randomisation. Higher baseline CBF in the insula predicted greater weight gain between baseline and 1-month post-randomisation and between baseline and 4-months post-randomisation.

CONCLUSIONS

This exploratory pilot study identified rTMS treatment related changes in CBF in adults with SE-AN and these were associated with changes in weight. Our preliminary findings also suggest that CBF (as measured by ASL fMRI) may be a marker of rTMS treatment response in this patient group. Future rTMS studies in AN should employ longitudinal neuroimaging to further explore the neurobiological changes related to rTMS treatment.

TRIAL REGISTRATION

ISRCTN14329415 , registered 23rd July 2015.

Is set-shifting and central coherence in anorexia nervosa influenced by body mass index, anxiety or depression? A systematic review

BACKGROUND

Anorexia nervosa (AN) is a severe eating disorder, recognized by a relentless pursuit for thinness and extreme low body weight. The disorder is often accompanied by comorbid disorders such as anxiety and depression, and altered neuropsychological function in terms of poor set-shifting and reduced central coherence. The aim of this review was to evaluate whether neuropsychological impairments in AN are influenced by body mass index, anxiety or depression.

METHOD

A systematic review approach was used, following the PRISMA guidelines for systematic reviews. Literature was identified via searches in PubMed, PsychInfo and Embase database, by using the search words [anorexia nervosa] AND [central coherence], and [anorexia nervosa] AND [set-shifting]. Studies were included if they were written in English, peer-reviewed, included individuals with AN, included tests measuring set-shifting and/or central coherence, investigated associations between set-shifting/central coherence with anxiety and/or depression and/or BMI. Risk of bias was assessed by using a critical appraisal checklist from the Joanna Briggs Institute. Results were summarized in a narrative synthesis.

RESULTS

Although results are heterogeneous, the majority of studies report that neither body mass index (BMI), anxiety or depression is associated with altered central coherence and set-shifting in individuals with AN.

CONCLUSIONS

Findings indicate that BMI, depression and anxiety does not influence neuropsychological function in AN, suggesting that it could be a characteristic of the disorder. A complete understanding of predisposing, precipitating and maintaining factors in AN needs to be addressed in future research. This could contribute to the development of better and more targeted treatment strategies.

Clinicians' views on neuromodulation as a treatment for eating disorders: A qualitative study

BACKGROUND

Neuromodulation techniques, such as repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS) and deep brain stimulation (DBS), are emerging as promising treatment options in eating disorders (EDs). To date, the views of ED clinicians regarding these interventions have not been explored.

METHODS

Eighteen clinicians were recruited from a specialist ED Service in London, UK. Following a short educational presentation on rTMS, tDCS and DBS, they completed a semi-structured interview to explore their views on the use of these treatment options in EDs.

RESULTS

Clinician knowledge of neuromodulation techniques was low. They raised safety and ethical (particularly capacity to consent) concerns mainly with regard to DBS. Neuromodulation treatments were considered most appropriate as an adjunct to psychotherapy and for patients with severe, enduring illness (who had completed previous psychological treatments).

CONCLUSIONS

Improving clinicians' knowledge and understanding of neuromodulation is fundamental for bridging the gap between research and clinical work. This is especially so given the predominance of psychological theory and practice in the treatment of EDs.

The efficacy of virtual reality in the treatment of binge-purging eating disorders: A meta-analysis

OBJECTIVE

This paper aims to examine the efficacy of virtual reality (VR)-enhanced cognitive behavioural therapy (CBT) in the treatment of binge-purging type eating disorders compared to CBT.

METHOD

Four electronic literature databases were searched to retrieve eligible randomised controlled trials (RCTs). The Preferred Reporting Items for Systematic Reviews and Meta-Analyses was used to select eligible studies. Meta-analyses of extracted data were then conducted by RevMan 5.3 software.

RESULTS

Six RCTs totalling 297 participants were included. Results showed significantly larger decreases in the frequency of binges in participants who underwent VR-enhanced CBT compared to CBT. However, there was no statistically significant difference in the change in body mass index or frequency of purges. Additionally, there were significantly larger decreases in situation-induced body dissatisfaction in participants who underwent VR-enhanced CBT compared to CBT, but no significant difference in improvement of overall body satisfaction.

CONCLUSION

VR-enhanced CBT shows greater efficacy than CBT in reducing situation-induced body dissatisfaction and frequency of binges. Our results highlight the potential of VR in helping patients develop coping strategies to food/situational triggers. Future RCTs may benefit from recruiting more participants to reduce the impact of drop-outs on outcome data and blinding post-intervention assessors to reduce risk of bias.

Fat Addiction: Psychological and Physiological Trajectory

Obesity has become a major public health concern worldwide due to its high social and economic burden, caused by its related comorbidities, impacting physical and mental health. Dietary fat is an important source of energy along with its rewarding and reinforcing properties. The nutritional recommendations for dietary fat vary from one country to another; however, the dietary reference intake (DRI) recommends not consuming more than 35% of total calories as fat. Food rich in fat is hyperpalatable, and is liable to be consumed in excess amounts. Food addiction as a concept has gained traction in recent years, as some aspects of addiction have been demonstrated for certain varieties of food. Fat addiction can be a diagnosable condition, which has similarities with the construct of addictive disorders, and is distinct from eating disorders or normal eating behaviors. Psychological vulnerabilities like attentional biases have been identified in individuals described to be having such addiction. Animal models have provided an opportunity to explore this concept in an experimental setting. This discussion sheds light on fat addiction, and explores its physiological and psychological implications. The discussion attempts to collate the emerging literature on addiction to fat rich diets as a prominent subset of food addiction. It aims at addressing the clinical relevance at the community level, the psychological correlates of such fat addiction, and the current physiological research directions.

Same, same but different: Attention bias for food cues in adults and adolescents with anorexia nervosa

OBJECTIVE

Attention processing for food may be biased in people with Anorexia Nervosa (AN). However, previous studies have had inconsistent results. This is likely to be due to indirect assessment of attention, which does not inform on the underlying attention processes, and/or the heterogeneity of participants across studies, testing either adults or adolescents with AN, that is, people at very different developmental and illness stages.

METHOD

Eye-tracking was employed as a direct assessment of attention during a visual probe task with food versus non-food pictures. Attention bias for food was measured in 39 adults and 34 adolescents with AN and in 53 adults and 31 adolescents without AN.

RESULTS

All participants had a direction bias for food, specifically for high-calorie food. However, adults with AN subsequently avoided maintaining attention on food versus non-food cues, compared to adults without AN. Adolescents with or without AN demonstrated increased attention maintenance on food versus non-food cues, and, contrary to our hypothesis, did not differ in their attention bias for food cues. Accordingly, adults with AN differed significantly from adolescents with AN in attention maintenance for food cues: while adolescents with AN showed significantly increased attention maintenance on food stimuli, adults avoided maintaining attention on food cues.

DISCUSSION

Adults with AN may apply attention strategies to facilitate restrictive eating. This strategy is absent in adolescents with AN. This difference in food-related attention bias between adolescents and adults with AN suggests that attention biases develop over time as the illness progresses.

Approach bias modification training in bulimia nervosa and binge-eating disorder: A pilot randomized controlled trial

OBJECTIVE

Bulimia nervosa (BN) and binge-eating disorder (BED) are associated with poorly controlled approach behavior toward food resulting in binge eating. Approach bias modification (ABM) may reduce these automatic action tendencies (i.e., approach bias) toward food and may thus decrease binge eating and related symptoms.

METHOD

A total of 56 patients with BN/BED participated in this double-blind, randomized controlled trial (RCT) comparing real and sham ABM. The real ABM condition adopted an implicit learning paradigm in which participants were trained to show avoidance behavior in response to food cues. Participants in the sham condition used a similar task but were not trained to avoid food cues. Both conditions comprised 10 training sessions within 4 weeks.

RESULTS

Participants in both groups experienced significant reductions in binge eating, eating disorder symptoms, trait food craving, and food cue reactivity. Real ABM tended to result in greater reductions in eating disorder symptoms than sham ABM. Food intake, approach bias, and attention bias toward food did not change.

DISCUSSION

This is the first RCT on ABM in eating disorders. The findings provide limited support for the efficacy of ABM in BN/BED and pose questions regarding its active ingredients and its usefulness as a stand-alone treatment for eating disorders.

Anorexia Nervosa and a Lost Emotional Self: A Psychological Formulation of the Development, Maintenance, and Treatment of Anorexia Nervosa

In this paper, we argue that Anorexia Nervosa (AN) can be explained as arising from a 'lost sense of emotional self.' We begin by briefly reviewing evidence accumulated to date supporting the consensus that a complex range of genetic, biological, psychological, and socio-environmental risk and maintenance factors contribute to the development and maintenance of AN. We consider how current interventions seek to tackle these factors in psychotherapy and potential limitations. We then propose our theory that many risk and maintenance factors may be unified by an underpinning explanation of emotional processing difficulties leading to a lost sense of 'emotional self.' Further, we discuss how, once established, AN becomes 'self-perpetuating' and the 'lost sense of emotional self' relentlessly deepens. We outline these arguments in detail, drawing on empirical and neuroscientific data, before discussing the implications of this model for understanding AN and informing clinical intervention. We argue that experiential models of therapy (e.g., emotion-focused therapy; schema therapy) be employed to achieve emergence and integration of an 'emotional self' which can be flexibly and adaptively used to direct an individual's needs and relationships. Furthermore, we assert that this should be a primary goal of therapy for adults with established AN.

Therapeutic potential of deep brain stimulation of the nucleus accumbens in morbid obesity

OBJECTIVE

Morbid obesity is a growing problem worldwide. The current treatment options have limitations regarding effectiveness and complication rates. New treatment modalities are therefore warranted. One of the options is deep brain stimulation (DBS) of the nucleus accumbens (NAC). This review aims to summarize the current knowledge on NAC-DBS for the treatment of morbid obesity.

METHODS

Studies were obtained from multiple electronic bibliographic databases, supplemented with searches of reference lists. All animal and human studies reporting on the effects of NAC-DBS on body weight in morbidly obese patients were included. Articles found during the search were screened by 2 reviewers, and when deemed applicable, the relevant data were extracted.

RESULTS

Five relevant animal experimental papers were identified, pointing toward a beneficial effect of high-frequency stimulation of the lateral shell of the NAC. Three human case reports show a beneficial effect of NAC-DBS on body weight in morbidly obese patients.

CONCLUSIONS

The available literature supports NAC-DBS to treat morbid obesity. The number of well-conducted animal studies, however, is very limited. Also, the optimal anatomical position of the DBS electrode within the NAC, as well as the optimal stimulation parameters, has not yet been established. These matters need to be addressed before this strategy can be considered for human clinical trials.

The acceptability, feasibility, and possible benefits of a neurobiologically-informed 5-day multifamily treatment for adults with anorexia nervosa

OBJECTIVE

Novel treatments for adults with anorexia nervosa (AN) are lacking. Recent scientific advances have identified neurobiologically-driven temperament contributors to AN symptoms that may guide development of more effective treatments. This preliminary study evaluates the acceptability, feasibility and possible benefits of a multicenter open trial of an intensive 5-day neurobiologically-informed multifamily treatment for adults with AN and their supports (SU). The temperament-focused treatment combines psychoeducation of AN neurobiology and SU involvement to develop skills to manage traits contributing to disease chronicity.

METHOD

Fifty-four adults with AN and at least one SU (n = 73) received the 5-day treatment. Acceptability, feasibility, and attrition were measured post-treatment. Clinical outcome (BMI, eating disorder psychopathology, family function) was assessed post-treatment and at >3-month follow-up.

RESULTS

The treatment had low attrition, with only one drop-out. Patients and SU rated the intervention as highly acceptable, and clinicians reported good feasibility. At post-treatment, patients demonstrated significantly increased BMI, reduced eating disorder psychopathology, and improved family function. Benefits were maintained in the 39 patients who completed follow-up assessment, with 62% reporting full or partial remission.

DISCUSSION

Preliminary results are promising and suggest this novel treatment is feasible and acceptable. To establish treatment efficacy, fully-powered randomized controlled trials are necessary.

Hungry brains: A meta-analytical review of brain activation imaging studies on food perception and appetite in obese individuals

The dysregulation of food intake in chronic obesity has been explained by different theories. To assess their explanatory power, we meta-analyzed 22 brain-activation imaging studies. We found that obese individuals exhibit hyper-responsivity of the brain regions involved in taste and reward for food-related stimuli. Consistent with a Reward Surfeit Hypothesis, obese individuals exhibit a ventral striatum hyper-responsivity in response to pure tastes, particularly when fasting. Furthermore, we found that obese subjects display more frequent ventral striatal activation for visual food cues when satiated: this continued processing within the reward system, together with the aforementioned evidence, is compatible with the Incentive Sensitization Theory. On the other hand, we did not find univocal evidence in favor of a Reward Deficit Hypothesis nor for a systematic deficit of inhibitory cognitive control. We conclude that the available brain activation data on the dysregulated food intake and food-related behavior in chronic obesity can be best framed within an Incentive Sensitization Theory. Implications of these findings for a brain-based therapy of obesity are briefly discussed.

Neuroimaging in bulimia nervosa and binge eating disorder: a systematic review

OBJECTIVE

In recent decades there has been growing interest in the use of neuroimaging techniques to explore the structural and functional brain changes that take place in those with eating disorders. However, to date, the majority of research has focused on patients with anorexia nervosa. This systematic review addresses a gap in the literature by providing an examination of the published literature on the neurobiology of individuals who binge eat; specifically, individuals with bulimia nervosa (BN) and binge eating disorder (BED).

METHODS

A systematic review was conducted in accordance with PRISMA guidelines using PubMed, PsycInfo, Medline and Web of Science, and additional hand searches through reference lists. 1,003 papers were identified in the database search. Published studies were included if they were an original research paper written in English; studied humans only; used samples of participants with a diagnosed eating disorder characterised by recurrent binge eating; included a healthy control sample; and reported group comparisons between clinical groups and healthy control groups.

RESULTS

Thirty-two papers were included in the systematic review. Significant heterogeneity in the methods used in the included papers coupled with small sample sizes impeded the interpretation of results. Twenty-one papers utilised functional Magnetic Resonance Imaging (fMRI); seven papers utilized Magnetic Resonance Imaging (MRI) with one of these using both MRI and Positron Emission Technology (PET); three studies used Single-Photon Emission Computed Tomography (SPECT) and one study used PET only. A small number of consistent findings emerged in individuals in the acute phase of illness with BN or BED including: volume reduction and increases across a range of areas; hypoactivity in the frontostriatal circuits; and aberrant responses in the insula, amygdala, middle frontal gyrus and occipital cortex to a range of different stimuli or tasks; a link between illness severity in BN and neural changes; diminished attentional capacity and early learning; and in SPECT studies, increased rCBF in relation to disorder-related stimuli.

CONCLUSIONS

Studies included in this review are heterogenous, preventing many robust conclusions from being drawn. The precise neurobiology of BN and BED remains unclear and ongoing, large-scale investigations are required. One clear finding is that illness severity, exclusively defined as the frequency of binge eating or bulimic episodes, is related to greater neural changes. The results of this review indicate additional research is required, particularly extending findings of reduced cortical volumes and diminished activity in regions associated with self-regulation (frontostriatal circuits) and further exploring responses to disorder-related stimuli in people with BN and BED.

Neurostimulation in Clinical and Sub-clinical Eating Disorders: A Systematic Update of the Literature

INTRODUCTION

Whilst psychological therapies are the main approach to treatment of eating disorders (EDs), advances in aetiological research suggest the need for the development of more targeted, brain-focused treatments. A range of neurostimulation approaches, most prominently repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS) and deep brain stimulation (DBS), are rapidly emerging as potential novel interventions. We have previously reviewed these techniques as potential treatments of EDs.

AIM

To provide an update of the literature examining the effects of DBS, rTMS and tDCS on eating behaviours, body weight and associated symptoms in people with EDs and relevant analogue populations.

METHODS

Using PRISMA guidelines, we reviewed articles in PubMed, Web of Science, and PsycINFO from 1st January 2013 until 14th August 2017, to update our earlier search. Studies assessing the effects of neurostimulation techniques on eating and weight-related outcomes in people with EDs and relevant analogue populations were included. Data from both searches were combined.

RESULTS

We included a total of 32 studies (526 participants); of these, 18 were newly identified by our update search. Whilst findings are somewhat mixed for bulimia nervosa, neurostimulation techniques have shown potential in the treatment of other EDs, in terms of reduction of ED and associated symptoms. Studies exploring cognitive, neural, and hormonal correlates of these techniques are also beginning to appear.

CONCLUSIONS

Neurostimulation approaches show promise as treatments for EDs. As yet, large wellconducted randomised controlled trials are lacking. More information is needed about treatment targets, stimulation parameters and mechanisms of action.

Neuromodulation and neurofeedback treatments in eating disorders and obesity

PURPOSE OF REVIEW

Psychological interventions are the treatment of choice for most eating disorders; however, significant proportions of patients do not recover with these. Advances in understanding of the neurobiology of eating disorders have led to the development of targeted treatments, such as deep brain stimulation (DBS), noninvasive brain stimulation (NIBS), and neurofeedback. We review the emerging clinical evidence for the use of these interventions in eating disorders and obesity, together with their theoretical rationale. Finally, we reflect on future developments.

RECENT FINDINGS

During the last 20 months, seven case studies/series and seven randomized controlled trials (RCTs) of NIBS or neurofeedback in different eating disorders, obesity, or food craving have appeared. These have largely had promising results. One NIBS trial, using a multisession protocol, was negative. A case series of subcallosal DBS in anorexia nervosa has also shown promise. A search of trial registries identified a further 21 neuromodulation/feedback studies in progress, indicating that neuromodulation/feedback is an area of growing interest.

SUMMARY

At present, neuromodulation and neurofeedback are largely experimental interventions; however, growing understanding of the mechanisms involved, together with the rising number of studies in this area, means that the clinical utility of these interventions is likely to become clearer soon.

Affective temperaments in anorexia nervosa: The relevance of depressive and anxious traits

BACKGROUND

Affective temperaments have been so far understudied in anorexia nervosa (AN) despite the relevance of personality and both affective and anxious comorbidity with regard to vulnerability, course, and outcome of this deadly disorder.

METHODS

Ninety-eight female inpatients diagnosed with AN and 131 healthy controls (HCs) were enrolled in this study and completed the Temperament Evaluation of Memphis, Pisa, Paris and San Diego Autoquestionnaire (TEMPS-A) in addition to assessments of eating psychopathology, depression, and anxiety.

RESULTS

AN patients and HCs differed in all affective temperaments. The diagnostic subtypes of AN differed as well with binge-purging individuals being more cyclothymic and anxious than those with restricting-type AN. TEMPS-A scores correlated with body mass index and eating psychopathology but not with duration of illness. Concerning comorbidity, grater scores on the depressive and lower scores on the hyperthymic temperaments were found in depressed patients. Those who had either an anxious or irritable temperament were significantly more diagnosed with an anxious disorder than those who did not show this temperament. When logistic regression was performed, high depressive/low hyperthymic and high irritable/anxious traits resulted to be associated with depressive and anxious comorbidity, respectively, independently of confounding factors.

LIMITATIONS

Cross-sectional design, some patients on medications, few baseline clinical differences between diagnostic subtypes, no other personality assessments.

CONCLUSIONS

An affective continuum strongly associated with mood and anxious comorbidity emerged in AN. Such an evaluation could have several research and clinical implications given the need of improving treatment individualization and early interventions for such a complex disorder.

Depictive and metric body size estimation in anorexia nervosa and bulimia nervosa: A systematic review and meta-analysis

A distorted representation of one's own body is a diagnostic criterion and core psychopathology of both anorexia nervosa (AN) and bulimia nervosa (BN). Despite recent technical advances in research, it is still unknown whether this body image disturbance is characterized by body dissatisfaction and a low ideal weight and/or includes a distorted perception or processing of body size. In this article, we provide an update and meta-analysis of 42 articles summarizing measures and results for body size estimation (BSE) from 926 individuals with AN, 536 individuals with BN and 1920 controls. We replicate findings that individuals with AN and BN overestimate their body size as compared to controls (ES=0.63). Our meta-regression shows that metric methods (BSE by direct or indirect spatial measures) yield larger effect sizes than depictive methods (BSE by evaluating distorted pictures), and that effect sizes are larger for patients with BN than for patients with AN. To interpret these results, we suggest a revised theoretical framework for BSE that accounts for differences between depictive and metric BSE methods regarding the underlying body representations (conceptual vs. perceptual, implicit vs. explicit). We also discuss clinical implications and argue for the importance of multimethod approaches to investigate body image disturbance.

Virtual Reality as a Promising Strategy in the Assessment and Treatment of Bulimia Nervosa and Binge Eating Disorder: A Systematic Review

Several lines of evidence suggest that Virtual Reality (VR) has a potential utility in eating disorders. The objective of this study is to review the literature on the use of VR in bulimia nervosa (BN) and binge eating disorder (BED). Using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement for reporting systematic reviews, we performed a PubMed, Web of Knowledge and SCOPUS search to identify studies employing VR in the assessment and treatment of BN and BED. The following search terms were used: "virtual reality", "eating disorders", "binge eating", and "bulimia nervosa". From the 420 articles identified, 19 were selected, nine investigated VR in assessment and 10 were treatment studies (one case-report, two non-controlled and six randomized controlled trials). The studies using VR in BN and BED are at an early stage. However, considering the available evidence, the use of VR in the assessment of those conditions showed some promise in identifying: (1) how those patients experienced their body image; and (2) environments or specific kinds of foods that may trigger binge-purging cycle. Some studies using VR-based environments associated to cognitive behavioral techniques showed their potential utility in improving motivation for change, self-esteem, body image disturbances and in reducing binge eating and purging behavior.

Food matters: how the microbiome and gut-brain interaction might impact the development and course of anorexia nervosa

Anorexia nervosa (AN) is one of the most common chronic illnesses in female adolescents and exhibits the highest mortality risk of all psychiatric disorders. Evidence for the effectiveness of psychotherapeutic or psychopharmacological interventions is weak. Mounting data indicate that the gut microbiome interacts with the central nervous system and the immune system by neuroendocrine, neurotransmitter, neurotrophic and neuroinflammatory afferent and efferent pathways. There is growing evidence that the gut microbiota influences weight regulation and psychopathology, such as anxiety and depression. This article reviews how the gut-brain interaction may impact the development and course of AN. A "leaky gut", characterized by antigens traversing the intestinal wall, was demonstrated in an animal model of AN, and could underlie the low-grade inflammation and increased risk of autoimmune diseases found in AN. Moreover, starvation has a substantial impact on the gut microbiome, and diets used for re-nutrition based on animal products may support the growth of bacteria capable of triggering inflammation. As there is currently no empirically derived agreement on therapeutic re-nourishment in AN, this review discusses how consideration of gut-brain interactions may be important for treatment regarding the determination of target weight, rapidity of weight gain, refeeding methods and composition of the diet which might all be of importance to improve long-term outcome of one of the most chronic psychiatric disorders of adolescence.

Advancing our understanding of the neurobiology of anorexia nervosa: translation into treatment

A wealth of studies has investigated the neurobiological underpinnings of anorexia nervosa. In our letter to the editor, we point to a number of ways in which the advances in our understanding of the neurobiology of anorexia nervosa - focusing on neuroimaging studies of brain structure and function - can be translated into treatment. We point to how such advances can: inform psychological treatment, be implemented in psychoeducation, point to novel therapeutic targets, lead to the identification of biomarkers, and expand our vocabulary for how we think and talk about anorexia nervosa.

A comprehensive review of psychodynamic treatments for eating disorders

PURPOSE

To comprehensively review the existing literature on the effectiveness of psychodynamic psychotherapies in eating disorders (EDs) and to stimulate both debate and research on this topic.

METHODS

Online and hand searches were conducted to identify papers published between 1980 and 2015 on psychodynamic treatments delivered to adults with anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED).

RESULTS

A total of 47 studies were finally included in this review. Fifteen studies were available for AN, 9 for BN, 12 for BED, and 11 for samples with mixed diagnoses. Several methodological flaws emerged, but overall psychodynamic interventions showed promising results at the end of treatment and follow-up, when available.

CONCLUSIONS

The body of literature on psychodynamic treatments is sparse and sometimes methodologically questionable; nevertheless, current data provide support to the effectiveness of these interventions, particularly for AN. However, both a defined approach (focus, themes, and techniques) and randomized controlled trials (RCTs) are warranted to clarify the effectiveness of psychodynamic psychotherapies.

An Integrative Bio-Psycho-Social Theory of Anorexia Nervosa

The need for novel approaches to understanding and treating anorexia nervosa (AN) is well recognized. The aim of this paper is to describe an integrative bio-psycho-social theory of maintaining factors in AN. We took a triangulation approach to develop a clinically relevant theory with face validity and internal consistency. We developed theoretical ideas from our clinical practice and reviewed theoretical ideas within the eating disorders and wider bio-psycho-social literature. The synthesis of these ideas and concepts into a clinically meaningful framework is described here. We suggest eight key factors central to understanding the maintenance and treatment resistance of anorexia nervosa: genetic or experiential predisposing factors; dysfunctional feelings processing and regulation systems; excessive vulnerable feelings; 'feared self' beliefs; starvation as a maladaptive physiological feelings regulation mechanism; maladaptive psychological coping modes; maladaptive social behaviour; and unmet physical and psychological core needs. Each of these factors serves to maintain the disorder. The concept of universal physical and psychological core needs can provide an underpinning integrative framework for working with this distinctly physical and psychological disorder. This framework could be used within any treatment model. We suggest that treatments which help address the profound lack of trust, emotional security and self-acceptance in this patient group will in turn address unmet needs and improve well-being. Copyright © 2016 John Wiley & Sons, Ltd.

KEY PRACTITIONER MESSAGE

The concept of unmet physical and psychological needs can be used as an underlying integrative framework for understanding and working with this patient group, alongside any treatment model. A functional understanding of the neuro-biological, physiological and psychological mechanisms involved in anorexia nervosa can help patients reduce self-criticism and shame. Fears about being or becoming fat, greedy, needy, selfish and unacceptable ('Feared Self') drive over-compensatory self-depriving behaviour ('Anorexic Self'). Psychological treatment for anorexia nervosa should emphasize a focus on feelings and fostering experiences of acceptance and trust. Treatment for patients with anorexia nervosa needs to be longer than current clinical practice.

The ABBA study - approach bias modification in bulimia nervosa and binge eating disorder: study protocol for a randomised controlled trial

BACKGROUND

The core symptoms of bulimia nervosa (BN) and binge eating disorder (BED) are recurrent episodes of binge eating. Despite negative psychological and physical consequences, BN/BED patients show uncontrollable approach tendencies towards food. This cognitive bias occurs at an early stage of information processing. Cognitive bias modification (CBM) directly targets such biases and has been shown to be effective in treating several mental disorders. In alcohol addiction, automatic action tendencies towards alcohol cues and relapse rates were successfully reduced by a specific form of CBM, termed approach bias modification. Based on these findings and data from a proof-of-concept study in people with high levels of food craving, CBM is considered a promising new treatment approach for BN/BED. Given the similarities between BN/BED and addictive disorders, the rationale for using approach bias modification appears to be particularly strong. The aim of the present study is to examine whether, compared to a sham training, computerised approach bias modification (10 sessions) can reduce binge-eating episodes in BN/BED patients from pre-treatment to follow-up. Additionally, we will investigate whether this CBM programme also reduces global eating disorder psychopathology, trait and cue-elicited food craving, food intake as well as approach and attentional bias towards visual food cues. Treatment acceptance will be determined by attrition rates and responses on a feedback form.

METHODS

This is a double-blind, randomised, placebo-controlled, parallel-group superiority trial with two parallel arms. A total of 54 BN/BED patients will be recruited. Approach bias towards food will be retrained by a computer task adopting an implicit learning paradigm. Patients in the control condition (sham) will conduct a similar task but will not be trained to avoid food cues. Methods against bias include public registration, randomisation by a central study office, standardisation of the treatments and blinding of assessors. Furthermore, the session number and duration will be equivalent in the two conditions.

DISCUSSION

This is the first registered randomised controlled trial of approach bias modification in a clinical BN/BED sample. Results from this study will provide an indication of the efficacy of approach bias modification training for BN/BED and the potential mechanisms of action underlying this treatment.

TRIAL REGISTRATION

DRKS00010231 (retrospectively registered on 24 March 2016; first version).

A Randomised Controlled Trial of Neuronavigated Repetitive Transcranial Magnetic Stimulation (rTMS) in Anorexia Nervosa

Background

Anorexia nervosa (AN) is associated with morbid fear of fatness, extreme food restriction and altered self-regulation. Neuroimaging data implicate fronto-striatal circuitry, including the dorsolateral prefrontal cortex (DLPFC).

Methods

In this double-blind parallel group study, we investigated the effects of one session of sham-controlled high-frequency repetitive transcranial magnetic stimulation (rTMS) to the left DLPFC (l-DLPFC) in 60 individuals with AN. A food exposure task was administered before and after the procedure to elicit AN-related symptoms.

Outcomes

The primary outcome measure was ‘core AN symptoms’, a variable which combined several subjective AN-related experiences. The effects of rTMS on other measures of psychopathology (e.g. mood), temporal discounting (TD; intertemporal choice behaviour) and on salivary cortisol concentrations were also investigated. Safety, tolerability and acceptability were assessed.

Results

Fourty-nine participants completed the study. Whilst there were no interaction effects of rTMS on core AN symptoms, there was a trend for group differences (p = 0.056): after controlling for pre-rTMS scores, individuals who received real rTMS had reduced symptoms post-rTMS and at 24-hour follow-up, relative to those who received sham stimulation. Other psychopathology was not altered differentially following real/sham rTMS. In relation to TD, there was an interaction trend (p = 0.060): real versus sham rTMS resulted in reduced rates of TD (more reflective choice behaviour). Salivary cortisol concentrations were unchanged by stimulation. rTMS was safe, well–tolerated and was considered an acceptable intervention.

Conclusions

This study provides modest evidence that rTMS to the l-DLPFC transiently reduces core symptoms of AN and encourages prudent decision making. Importantly, individuals with AN considered rTMS to be a viable treatment option. These findings require replication in multiple-session studies to evaluate therapeutic efficacy.

Trial Registration

www.Controlled-Trials.comISRCTN22851337

A systematic review of the relationship between eating, weight and inhibitory control using the stop signal task

Altered inhibitory control (response inhibition, reward-based inhibition, cognitive inhibition, reversal learning) has been implicated in eating disorders (EDs) and obesity. It is unclear, however, how different types of inhibitory control contribute to eating and weight-control behaviours. This review evaluates the relationship between one aspect of inhibitory control (a reactive component of motor response inhibition measured by the stop signal task) and eating/weight in clinical and non-clinical populations. Sixty-two studies from 58 journal articles were included. Restrained eaters had diminished reactive inhibitory control compared to unrestrained eaters, and showed greatest benefit to their eating behaviour from manipulations of inhibitory control. Obese individuals may show less reactive inhibitory control but only in the context of food-specific inhibition or after executive resources are depleted. Of the limited studies in EDs, the majority found no impairment in reactive inhibitory control, although findings are inconsistent. Thus, altered reactive inhibitory control is related to some maladaptive eating behaviours, and hence may provide a therapeutic target for behavioural manipulations and/or neuromodulation. However, other types of inhibitory control may also contribute. Methodological and theoretical considerations are discussed.

Clinical outcomes and neural correlates of 20 sessions of repetitive transcranial magnetic stimulation in severe and enduring anorexia nervosa (the TIARA study): study protocol for a randomised controlled feasibility trial

BACKGROUND

Anorexia nervosa (AN) is a serious mental disorder with multiple comorbidities and complications. In those with a severe and enduring form of the illness (SEED-AN), treatment responsivity is poor and the evidence base limited. Thus, there is a need for novel treatment strategies. This paper describes the theoretical background and protocol of a feasibility randomised controlled trial (RCT) of real versus sham (placebo) therapeutic repetitive transcranial magnetic stimulation (rTMS) in SEED-AN. The aim of this trial is to obtain information that will guide decision making and protocol development in relation to a future large-scale RCT of rTMS in this group of patients, and also to assess the preliminary efficacy and neural correlates of rTMS treatment.

DESIGN

Forty-four adults from the community with a DSM-5 diagnosis of AN, an illness duration>3 years and a previous course of unsuccessful treatment will be randomly allocated to receive 20 sessions of either real or sham rTMS, in a parallel group design. As this is a feasibility study, no primary outcome has been defined and a broad range of outcome variables will be examined. These include weight/body mass index (BMI), eating disorder psychopathology, other psychopathology (for example, depression, anxiety), quality of life, neuropsychological processes (such as self-regulation, attentional bias and food choice behaviour), neuroimaging measures (that is, changes in brain structure or function), tolerability and acceptability of rTMS, and additional service utilisation. The feasibility of conducting a large-scale RCT of rTMS and the appropriateness of rTMS as a treatment for SEED-AN will be evaluated through: assessment of recruitment and retention rates, acceptability of random allocation, blinding success (allocation concealment), completion of treatment sessions and research assessments (baseline, post-treatment and follow-up assessments). The acceptability and tolerability of the treatment will be assessed via semi-structured interviews.

DISCUSSION

The effect sizes generated and other findings from this trial will inform a future large-scale RCT with respect to decisions on primary outcome measures and other aspects of protocol development. Additionally, results from this study will provide a preliminary indication of the efficacy of rTMS treatment for AN, the neural correlates of the illness, and potential biomarkers of clinical response.

TRIAL REGISTRATION

ISRCTN14329415 . Date of registration: 23 July 2015.

ESCAP Expert Paper: New developments in the diagnosis and treatment of adolescent anorexia nervosa--a European perspective

Anorexia nervosa is a potentially life-threatening disorder with a typical onset in adolescence and high rates of medical complications and psychiatric comorbidity. This article summarizes issues relating to classification in DSM-5 and presents a narrative review of key evidence-based medical and behavioral interventions for adolescent AN and subthreshold restricting eating disorders, mainly, but not exclusively published between 2012 and 2014. In addition, it systematically compares the clinical guidelines of four European countries (Germany, Spain, The Netherlands, and United Kingdom) and outlines common clinical practice, in relation to treatment settings, nutritional rehabilitation, family-oriented and individual psychotherapy, and psychopharmacological treatment. With the exception of family-based treatment, which is mainly evaluated and practiced in Anglo-American countries, the evidence base is weak, especially for medical interventions such as refeeding and pharmacological intervention. There is a need for common European research efforts, to improve the available evidence base and resulting clinical guidance.

Identifying neuroanatomical signatures of anorexia nervosa: a multivariate machine learning approach

BACKGROUND

There are currently no neuroanatomical biomarkers of anorexia nervosa (AN) available to make clinical inferences at an individual subject level. We present results of a multivariate machine learning (ML) approach utilizing structural neuroanatomical scan data to differentiate AN patients from matched healthy controls at an individual subject level.

METHOD

Structural neuroimaging scans were acquired from 15 female patients with AN (age = 20, s.d. = 4 years) and 15 demographically matched female controls (age = 22, s.d. = 3 years). Neuroanatomical volumes were extracted using the FreeSurfer software and input into the Least Absolute Shrinkage and Selection Operator (LASSO) multivariate ML algorithm. LASSO was 'trained' to identify 'novel' individual subjects as either AN patients or healthy controls. Furthermore, the model estimated the probability that an individual subject belonged to the AN group based on an individual scan.

RESULTS

The model correctly predicted 25 out of 30 subjects, translating into 83.3% accuracy (sensitivity 86.7%, specificity 80.0%) (p < 0.001; χ 2 test). Six neuroanatomical regions (cerebellum white matter, choroid plexus, putamen, accumbens, the diencephalon and the third ventricle) were found to be relevant in distinguishing individual AN patients from healthy controls. The predicted probabilities showed a linear relationship with drive for thinness clinical scores (r = 0.52, p < 0.005) and with body mass index (BMI) (r = -0.45, p = 0.01).

CONCLUSIONS

The model achieved a good predictive accuracy and drive for thinness showed a strong neuroanatomical signature. These results indicate that neuroimaging scans coupled with ML techniques have the potential to provide information at an individual subject level that might be relevant to clinical outcomes.

The processing of food stimuli in abnormal eating: a systematic review of electrophysiology

To update the knowledge about attentional processing of food stimuli, a systematic review of electrophysiological studies was conducted using PubMed, PsychInfo and Web of Knowledge (2000-2014). Twenty-one studies were included into a qualitative synthesis. Presentation of food and control pictures was used to analyze event-related potentials related to sensory processing and motivated attention. Results show consistent attentional bias towards food pictures compared with neutral pictures for patient and control groups. Group comparisons between individuals with abnormal-eating and healthy-eating participants were more inconsistent. Results suggest that temporal differences in the millisecond range are essential for the understanding of visual food processing. In obesity, early attention engagement to food is followed by relatice disengagement. Loss of control eating, as well as external and emotional eating, are associated with a sustained maintenance of attention towards high-caloric food. There is a lack of studies in anorexia nervosa, bulimia nervosa and binge eating disorder.

Neuroimaging and neuromodulation approaches to study eating behavior and prevent and treat eating disorders and obesity

Functional, molecular and genetic neuroimaging has highlighted the existence of brain anomalies and neural vulnerability factors related to obesity and eating disorders such as binge eating or anorexia nervosa. In particular, decreased basal metabolism in the prefrontal cortex and striatum as well as dopaminergic alterations have been described in obese subjects, in parallel with increased activation of reward brain areas in response to palatable food cues. Elevated reward region responsivity may trigger food craving and predict future weight gain. This opens the way to prevention studies using functional and molecular neuroimaging to perform early diagnostics and to phenotype subjects at risk by exploring different neurobehavioral dimensions of the food choices and motivation processes. In the first part of this review, advantages and limitations of neuroimaging techniques, such as functional magnetic resonance imaging (fMRI), positron emission tomography (PET), single photon emission computed tomography (SPECT), pharmacogenetic fMRI and functional near-infrared spectroscopy (fNIRS) will be discussed in the context of recent work dealing with eating behavior, with a particular focus on obesity. In the second part of the review, non-invasive strategies to modulate food-related brain processes and functions will be presented. At the leading edge of non-invasive brain-based technologies is real-time fMRI (rtfMRI) neurofeedback, which is a powerful tool to better understand the complexity of human brain-behavior relationships. rtfMRI, alone or when combined with other techniques and tools such as EEG and cognitive therapy, could be used to alter neural plasticity and learned behavior to optimize and/or restore healthy cognition and eating behavior. Other promising non-invasive neuromodulation approaches being explored are repetitive transcranial magnetic stimulation (rTMS) and transcranial direct-current stimulation (tDCS). Converging evidence points at the value of these non-invasive neuromodulation strategies to study basic mechanisms underlying eating behavior and to treat its disorders. Both of these approaches will be compared in light of recent work in this field, while addressing technical and practical questions. The third part of this review will be dedicated to invasive neuromodulation strategies, such as vagus nerve stimulation (VNS) and deep brain stimulation (DBS). In combination with neuroimaging approaches, these techniques are promising experimental tools to unravel the intricate relationships between homeostatic and hedonic brain circuits. Their potential as additional therapeutic tools to combat pharmacorefractory morbid obesity or acute eating disorders will be discussed, in terms of technical challenges, applicability and ethics. In a general discussion, we will put the brain at the core of fundamental research, prevention and therapy in the context of obesity and eating disorders. First, we will discuss the possibility to identify new biological markers of brain functions. Second, we will highlight the potential of neuroimaging and neuromodulation in individualized medicine. Third, we will introduce the ethical questions that are concomitant to the emergence of new neuromodulation therapies.

Temperament-based treatment for anorexia nervosa

Anorexia nervosa (AN) tends to be a chronic and deadly disorder with no proven treatments that reverse core symptoms in adults. New insight into neurobiological mechanisms that contribute to symptoms may support development of more effective interventions. We describe the development of a temperament-based treatment for AN on the basis of empirically supported models. It uses a systemized approach and takes into consideration an understanding of how neurobiological mechanisms are expressed through behaviour and personality and contribute to specific AN symptomatology. This model integrates the development of AN-focused constructive coping strategies with carer-focused strategies to manage temperament traits that contribute to AN symptomatology. This intervention is consistent with the recent Novel Interventions for Mental Disorders initiative mandating that treatment trials follow an experimental medicine approach by identifying underlying mechanisms that are directly targeted by the intervention to influence symptoms.