Neurosurgical Treatment of Anorexia Nervosa: Review of the Literature from Leucotomy to Deep Brain Stimulation

Ethics of deep brain stimulation for neuropsychiatric disorders

Deep Brain Stimulation (DBS) has emerged as a revolutionary neurosurgical technique with significant implications for the treatment of various neuropsychiatric disorders. Initially developed for movement disorders like Parkinson's disease, DBS has expanded to psychiatric conditions such as obsessive-compulsive disorder, depression, anorexia nervosa, dystonia, essential tremor, and Tourette's syndrome. This paper explores the clinical efficacy and ethical considerations of DBS in treating these disorders. While DBS has shown substantial promise in alleviating symptoms and improving quality of life, it raises ethical challenges, including issues of informed consent, patient selection, long-term management, and equitable access to treatment. The irreversible nature of DBS, potential adverse effects, and the high cost of the procedure necessitate a rigorous ethical framework to guide its application. The ongoing evolution of neuromodulation requires continuous ethical analysis and the development of guidelines to ensure that DBS is used responsibly and equitably across different patient populations. This paper underscores the need for a balanced approach that integrates clinical efficacy with ethical considerations to optimize patient outcomes and ensure sustainable practice.

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.

Rescue Anterior Capsulotomy after Failure of Nucleus Accumbens Deep Brain Stimulation in Anorexia Nervosa: A Case Report

Anorexia nervosa (AN) is a highly disabling mental disorder with high rates of morbidity and mortality. Few psychological treatments and pharmacotherapy are proven to be effective for adult AN. Two invasive stereotactic neurosurgical interventions, deep brain stimulation (DBS) and anterior capsulotomy, are now commonly used as investigational approaches for the treatment of AN. Here, we report the long-term safety and efficacy of rescue bilateral anterior capsulotomy after the failure of bilateral nucleus accumbens (NAcc)-DBS in an 18-year-old female patient with life-threatening and treatment-resistant restricting subtype AN. Improvements in the neuropsychiatric assessment were not documented 6 months after the NAcc-DBS. Rescue bilateral anterior capsulotomy was proposed and performed, resulting in a long-lasting restoration of body weight and a significant and sustained remission in AN core symptoms. The DBS pulse generator was exhausted 2 years after capsulotomy and removed 3 years postoperatively. No relapse was reported at the last follow-up (7 years after the first intervention). From this case, we suggest that capsulotomy could be a rescue treatment for patients with treatment-resistant AN after NAcc-DBS failure. Further well-controlled studies are warranted to validate our findings.

Stereotactic surgery on a female patient with severe chronic anorexia nervosa: 10-year follow-up

INTRODUCTION

Anorexia nervosa (AN) is a serious disease with a high rate of chronification. In chronic and serious cases, psychotherapeutic and pharmacological treatments are not sufficient to control the disease.

CASE REPORT

We present the case of a female patient with severe chronic restrictive anorexia nervosa resistant to psychomedical treatment. During the 31 years the illness evolved, the patient required multiple hospital admissions. With a body mass index (BMI) of 12.8 kg/m² and consequent risk of death, stereotactic cingulotomy was performed comprising bilateral blocking of the anterior cingulate cortex by stereotactic radiofrequency thermocoagulation, confirmed by tractography 5 years later. After 10 years of follow-up, the patient is clinically stable with an increased BMI and improved neuropsychological indicators.

DISCUSSION

Stereotactic surgery may be an option for patients with chronic anorexia nervosa where conventional treatments have proved insufficient.

Transcranial magnetic stimulation, deep brain stimulation, and other forms of neuromodulation for substance use disorders: Review of modalities and implications for treatment

Given the high prevalence of individuals diagnosed with substance use disorder, along with the elevated rate of relapse following treatment initiation, investigating novel approaches and new modalities for substance use disorder treatment is of vital importance. One such approach involves neuromodulation which has been used therapeutically for neurological and psychiatric disorders and has demonstrated positive preliminary findings for the treatment of substance use disorder. The following article provides a review of several forms of neuromodulation which warrant consideration as potential treatments for substance use disorder. PubMed, PsycINFO, Ovid MEDLINE, and Web of Science were used to identify published articles and clinicaltrials.gov was used to identify currently ongoing or planned studies. Search criteria for Brain Stimulation included the following terminology: transcranial direct current stimulation, transcranial magnetic stimulation, theta burst stimulation, deep brain stimulation, vagus nerve stimulation, trigeminal nerve stimulation, percutaneous nerve field stimulation, auricular nerve stimulation, and low intensity focused ultrasound. Search criteria for Addiction included the following terminology: addiction, substance use disorder, substance-related disorder, cocaine, methamphetamine, amphetamine, alcohol, nicotine, tobacco, smoking, marijuana, cannabis, heroin, opiates, opioids, and hallucinogens. Results revealed that there are currently several forms of neuromodulation, both invasive and non-invasive, which are being investigated for the treatment of substance use disorder. Preliminary findings have demonstrated the potential of these various neuromodulation techniques in improving substance treatment outcomes by reducing those risk factors (e.g. substance craving) associated with relapse. Specifically, transcranial magnetic stimulation has shown the most promise with several well-designed studies supporting the potential for reducing substance craving. Deep brain stimulation has also shown promise, though lacks well-controlled clinical trials to support its efficacy. Transcranial direct current stimulation has also demonstrated promising results though consistently designed, randomized trials are also needed. There are several other forms of neuromodulation which have not yet been investigated clinically but warrant further investigation given their mechanisms and potential efficacy based on findings from other studied indications. In summary, given promising findings in reducing substance use and craving, neuromodulation may provide a non-pharmacological option as a potential treatment and/or treatment augmentation for substance use disorder. Further research investigating neuromodulation, both alone and in combination with already established substance use disorder treatment (e.g. medication treatment), warrants consideration.

Brain Stimulation in Eating Disorders: State of the Art and Future Perspectives

The management of eating disorders (EDs) is still difficult and few treatments are effective. Recently, several studies have described the important contribution of non-invasive brain stimulation (repetitive transcranial magnetic stimulation, transcranial direct current stimulation, and electroconvulsive therapy) and invasive brain stimulation (deep brain stimulation and vagal nerve stimulation) for ED management. This review summarizes the available evidence supporting the use of brain stimulation in ED. All published studies on brain stimulation in ED as well as ongoing trials registered at clinicaltrials.gov were examined. Articles on neuromodulation research and perspective articles were also included. This analysis indicates that brain stimulation in EDs is still in its infancy. Literature data consist mainly of case reports, cases series, open studies, and only a few randomized controlled trials. Consequently, the evidence supporting the use of brain stimulation in EDs remains weak. Finally, this review discusses future directions in this research domain (e.g., sites of modulation, how to enhance neuromodulation efficacy, personalized protocols).

Recent advances in therapies for eating disorders

Eating disorders are serious psychiatric illnesses with high rates of morbidity and mortality. Effective treatments have traditionally included behaviorally focused therapies as well as several medication strategies. Recent years have seen promising developments in these treatments, including additional support for family-based approaches for children and adolescents, new evidence for "third-wave" behavioral therapies, and new support for the use of lisdexamfetamine for binge eating disorder and olanzapine for anorexia nervosa. Case study and pilot data are beginning to show limited support for neuromodulatory interventions targeting brain regions thought to be involved in eating disorders. This review summarizes treatment developments over the last several years and points towards future directions for the field.

Deep brain stimulation for the treatment of severe intractable anorexia nervosa

Anorexia nervosa (AN) is a challenging multifactorial disorder with the highest mortality rate among all psychiatric disorders. Due to the low rate of long-term treatment success, new treatment options are needed. Here, we review Deep Brain Stimulation (DBS) as a treatment of Severe Intractable AN. The mechanisms of AN have shown significant involvement of the central nervous system especially the same brain regions which are involved with obsessive-compulsive disorder (OCD) and major depressive disorder (MDD). AN and OCD display many similarities in psychiatric practice such as compulsive behaviours and anxiety levels, which are related to networks in the brain, that can be altered using DBS. Our literature search revealed 8 studies totalling 28 individuals with AN and comorbid OCD or MDD. The most common stereotactic targets included the sub-callosal cingulate cortex (Brodmann area 25)/medial forebrain bundle (MFB) for AN and comorbid MDD and nucleus accumbens (NAc)/ventral striatum for AN and comorbid OCD. In most cases bilateral DBS of various structures of the reward system achieved good results in BMI, and core AN symptoms and psychiatric comorbidities showed sustained improvement. DBS is a promising treatment modality for AN and comorbid OCD or MDD. These results highlight promise and hope for patients with AN. However, further studies with larger patient populations are needed to shed light on the long-term outcomes of DBS and its effects in AN treatment.

Advances in the treatment of anorexia nervosa: a review of established and emerging interventions

BACKGROUND

Anorexia nervosa (AN) is a disabling, deadly and costly mental disorder. Until recently, treatment recommendations were based on expert opinion and limited evidence. The aim of this systematic review is to synthesise recent evidence on established and emerging AN treatments and to forecast trends for future developments.

METHODS

We systematically review trials of established treatments and associated process outcome studies from the last 5 years, published since a previous review in this journal. 'Established' treatments were those that are widely used in AN, recommended by guidelines and/or have been tested in at least one large randomised controlled trial. Secondly, we summarise emerging treatments for AN, i.e. those that have only been (or are currently being) tested in proof-of concept, feasibility or pilot trials.

RESULTS

We identified 19 published trials of established treatments (15 of high or moderate quality), mostly assessing psychological therapies (n = 17). We also found 11 published trials of emerging treatments, and a total of 34 registered, as yet unpublished trials. Promising emerging treatments include cognitive remediation therapy, exposure therapy and non-invasive neuromodulation.

CONCLUSIONS

Evidence generation on the treatment of AN has dramatically accelerated, with our understanding of the role of family-based approaches for adolescents more nuanced and a range of psychological approaches available for the treatment of adults. Evidence on emerging treatments and from forthcoming trials suggests that there is a shift towards more targeted brain-based interventions. Future studies need to focus on elucidating mechanisms of action of treatments and what works best for whom.

The Moral Obligation to Prioritize Research Into Deep Brain Stimulation Over Brain Lesioning Procedures for Severe Enduring Anorexia Nervosa

Deep Brain Stimulation is currently being investigated as an experimental treatment for patients suffering from treatment-refractory AN, with an increasing number of case reports and small-scale trials published. Although still at an exploratory and experimental stage, initial results have been promising. Despite the risks associated with an invasive neurosurgical procedure and the long-term implantation of a foreign body, DBS has a number of advantageous features for patients with SE-AN. Stimulation can be fine-tuned to the specific needs of the particular patient, is relatively reversible, and the technique also allows for the crucial issue of investigating and comparing the effects of different neural targets. However, at a time when DBS is emerging as a promising investigational treatment modality for AN, lesioning procedures in psychiatry are having a renaissance. Of concern it has been argued that the two kinds of interventions should instead be understood as rivaling, yet "mutually enriching paradigms" despite the fact that lesioning the brain is irreversible and there is no evidence base for an effective target in AN. We argue that lesioning procedures in AN are unethical at this stage of knowledge and seriously problematic for this patient group, for whom self-control is particularly central to wellbeing. They pose a greater risk of major harms that cannot justify ethical equipoise, despite the apparent superiority in reduced short term surgical harms and lower cost.

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.

Long-Term Follow-up Study of MRI-Guided Bilateral Anterior Capsulotomy in Patients With Refractory Anorexia Nervosa

BACKGROUND

Anorexia nervosa (AN) is one of the most challenging psychiatric disorders to treat. The poor clinical outcomes warrant novel treatments for AN, especially in severe and persistent cases.

OBJECTIVE

To explore the feasibility of magnetic resonance imaging-guided bilateral anterior capsulotomy in the treatment of refractory AN.

METHODS

Seventy-four patients diagnosed with refractory AN who underwent capsulotomy completed this 3-yr follow-up study. Outcomes included body mass index (BMI) and results from a series of psychiatric scales (for obsessive, depressive, and anxious symptoms) that were implemented at baseline (presurgery), and 1 mo, 1 yr, and 3 yr after surgery.

RESULTS

Compared to presurgical levels, BMI increased significantly at 1-yr and 3-yr follow-ups. Compared to presurgery scores, psychiatric scale scores were significantly improved at 1-mo postsurgery, and continued to remain low at the 1-yr and 3-yr follow-ups. In addition, Mini-Mental State Examination (MMSE) scores were in the normal range during the long-term follow-up. The most common short-term side effects included urinary incontinence (n = 7), sleep disorders (n = 8), and fatigue (n = 6). Long-term complications included disinhibition (n = 6), memory loss (n = 3), and lethargy (n = 4). No patient in this study experienced death or disability.

CONCLUSION

Capsulotomy enabled patients with refractory AN to normalize their weight, especially those in life-threatening conditions. While it appears to be an acceptable life-saving treatment, it is indicated only when fulfilling strict criteria given its complications and irreversibility.

Deep Brain Stimulation in Anorexia Nervosa: Hope for the Hopeless or Exploitation of the Vulnerable? The Oxford Neuroethics Gold Standard Framework

Neurosurgical interventions for psychiatric disorders have a long and troubled history (1, 2) but have become much more refined in the last few decades due to the rapid development of neuroimaging and robotic technologies (2). These advances have enabled the design of less invasive techniques, which are more focused, such as deep brain stimulation (DBS) (3). DBS involves electrode insertion into specific neural targets implicated in pathological behavior, which are then repeatedly stimulated at adjustable frequencies. DBS has been used for Parkinson's disease and movement disorders since the 1960s (4-6) and over the last decade has been applied to treatment-refractory psychiatric disorders, with some evidence of benefit in obsessive-compulsive disorder (OCD), major depressive disorder, and addictions (7). Recent consensus guidelines on best practice in psychiatric neurosurgery (8) stress, however, that DBS for psychiatric disorders remains at an experimental and exploratory stage. The ethics of DBS-in particular for psychiatric conditions-is debated (1, 8-10). Much of this discourse surrounds the philosophical implications of competence, authenticity, personality, or identity change following neurosurgical interventions, but there is a paucity of applied guidance on neuroethical best practice in psychiatric DBS, and health-care professionals have expressed that they require more (11). This paper aims to redress this balance by providing a practical, applied neuroethical gold standard framework to guide research ethics committees, researchers, and institutional sponsors. We will describe this as applied to our protocol for a particular research trial of DBS in severe and enduring anorexia nervosa (SE-AN) (https://clinicaltrials.gov/ct2/show/NCT01924598, unique identifier NCT01924598), but believe it may have wider application to DBS in other psychiatric disorders.

The importance of the hypothalamo-pituitary-adrenal axis as a therapeutic target in anorexia nervosa

Anorexia nervosa (AN) is an eating disorder, mainly affecting women, with a lifetime prevalence of about 1%, that can run a chronic course. While an effective pharmacotherapy is lacking, it is hypothesized that the progesterone and type II glucocorticoid receptor antagonist mifepristone (RU486) might be useful, as it is well known that the hypothalamo-pituitary-adrenal axis (HPA) is activated in AN. Even if secondary to the eating disorder, an active HPA axis may contribute to maintaining the neuroendocrine, emotional and behavioral effects observed in AN. More specifically, it is suggested that the HPA axis interacts with limbic structures, including the insular and prefrontal cortices, to uphold the changes in interoceptive and emotional awareness seen in AN. As such, it is proposed that mifepristone (RU486) reverses these effects by acting on these limbic regions. In conclusion, the theoretical efficacy of mifepristone (RU486) in improving symptoms of AN should be tested in randomized clinical trials.

Anorexia nervosa: aetiology, assessment, and treatment

Anorexia nervosa is an important cause of physical and psychosocial morbidity. Recent years have brought advances in understanding of the underlying psychobiology that contributes to illness onset and maintenance. Genetic factors influence risk, psychosocial and interpersonal factors can trigger onset, and changes in neural networks can sustain the illness. Substantial advances in treatment, particularly for adolescent patients with anorexia nervosa, point to the benefits of specialised family-based interventions. Adults with anorexia nervosa too have a realistic chance of achieving recovery or at least substantial improvement, but no specific approach has shown clear superiority, suggesting a combination of re-nourishment and anorexia nervosa-specific psychotherapy is most effective. To successfully fight this enigmatic illness, we have to enhance understanding of the underlying biological and psychosocial mechanisms, improve strategies for prevention and early intervention, and better target our treatments through improved understanding of specific disease mechanisms.

Gyrification brain abnormalities as predictors of outcome in anorexia nervosa

Gyrification brain abnormalities are considered a marker of early deviations from normal developmental trajectories and a putative predictor of poor outcome in psychiatric disorders. The aim of this study was to explore cortical folding morphology in patients with anorexia nervosa (AN). A MRI brain study was conducted on 38 patients with AN, 20 fully recovered patients, and 38 healthy women. Local gyrification was measured with procedures implemented in FreeSurfer. Vertex-wise comparisons were carried out to compare: (1) AN patients and healthy women; (2) patients with a full remission at a 3-year longitudinal follow-up assessment and patients who did not recover. AN patients exhibited significantly lower gyrification when compared with healthy controls. Patients with a poor 3-year outcome had significantly lower baseline gyrification when compared to both healthy women and patients with full recovery at follow-up, even after controlling for the effects of duration of illness and gray matter volume. No significant correlation has been found between gyrification, body mass index, amount of weight loss, onset age, and duration of illness. Brain gyrification significantly predicted outcome at follow-up even after controlling for the effects of duration of illness and other clinical prognostic factors. Although the role of starvation in determining our findings cannot be excluded, our study showed that brain gyrification might be a predictor of outcome in AN. Further studies are needed to understand if brain gyrification abnormalities are indices of early neurodevelopmental alterations, the consequence of starvation, or the interaction between both factors.

Subcallosal Cingulate Connectivity in Anorexia Nervosa Patients Differs From Healthy Controls: A Multi-tensor Tractography Study

BACKGROUND

Anorexia nervosa is characterized by extreme low body weight and alterations in affective processing. The subcallosal cingulate regulates affect through wide-spread white matter connections and is implicated in the pathophysiology of anorexia nervosa.

OBJECTIVES

We examined whether those with treatment refractory anorexia nervosa undergoing deep brain stimulation (DBS) of the subcallosal white matter (SCC) show: (1) altered anatomical SCC connectivity compared to healthy controls, (2) white matter microstructural changes, and (3) microstructural changes associated with clinically-measured affect.

METHODS

Diffusion magnetic resonance imaging (dMRI) and deterministic multi-tensor tractography were used to compare anatomical connectivity and microstructure in SCC-associated white matter tracts. Eight women with treatment-refractory anorexia nervosa were compared to 8 age- and sex-matched healthy controls. Anorexia nervosa patients also completed affect-related clinical assessments presurgically and 12 months post-surgery.

RESULTS

(1) Higher (e.g., left parieto-occipital cortices) and lower (e.g., thalamus) connectivity in those with anorexia nervosa compared to controls. (2) Decreases in fractional anisotropy, and alterations in axial and radial diffusivities, in the left fornix crus, anterior limb of the internal capsule (ALIC), right anterior cingulum and left inferior fronto-occipital fasciculus. (3) Correlations between dMRI metrics and clinical assessments, such as low pre-surgical left fornix and right ALIC fractional anisotropy being related to post-DBS improvements in quality-of-life and depressive symptoms, respectively.

CONCLUSIONS

We identified widely-distributed differences in SCC connectivity in anorexia nervosa patients consistent with heterogenous clinical disruptions, although these results should be considered with caution given the low number of subjects. Future studies should further explore the use of affect-related connectivity and behavioral assessments to assist with DBS target selection and treatment outcome.

Royal Australian and New Zealand College of Psychiatrists clinical practice guidelines for the treatment of eating disorders

OBJECTIVES

This clinical practice guideline for treatment of DSM-5 feeding and eating disorders was conducted as part of the Royal Australian and New Zealand College of Psychiatrists (RANZCP) Clinical Practice Guidelines (CPG) Project 2013-2014.

METHODS

The CPG was developed in accordance with best practice according to the National Health and Medical Research Council of Australia. Literature of evidence for treatments of anorexia nervosa (AN), bulimia nervosa (BN), binge eating disorder (BED), other specified and unspecified eating disorders and avoidant restrictive food intake disorder (ARFID) was sourced from the previous RANZCP CPG reviews (dated to 2009) and updated with a systematic review (dated 2008-2013). A multidisciplinary working group wrote the draft CPG, which then underwent expert, community and stakeholder consultation, during which process additional evidence was identified.

RESULTS

In AN the CPG recommends treatment as an outpatient or day patient in most instances (i.e. in the least restrictive environment), with hospital admission for those at risk of medical and/or psychological compromise. A multi-axial and collaborative approach is recommended, including consideration of nutritional, medical and psychological aspects, the use of family based therapies in younger people and specialist therapist-led manualised based psychological therapies in all age groups and that include longer-term follow-up. A harm minimisation approach is recommended in chronic AN. In BN and BED the CPG recommends an individual psychological therapy for which the best evidence is for therapist-led cognitive behavioural therapy (CBT). There is also a role for CBT adapted for internet delivery, or CBT in a non-specialist guided self-help form. Medications that may be helpful either as an adjunctive or alternative treatment option include an antidepressant, topiramate, or orlistat (the last for people with comorbid obesity). No specific treatment is recommended for ARFID as there are no trials to guide practice.

CONCLUSIONS

Specific evidence based psychological and pharmacological treatments are recommended for most eating disorders but more trials are needed for specific therapies in AN, and research is urgently needed for all aspects of ARFID assessment and management.

EXPERT REVIEWERS

Associate Professor Susan Byrne, Dr Angelica Claudino, Dr Anthea Fursland, Associate Professor Jennifer Gaudiani, Dr Susan Hart, Ms Gabriella Heruc, Associate Professor Michael Kohn, Dr Rick Kausman, Dr Sarah Maguire, Ms Peta Marks, Professor Janet Treasure and Mr Andrew Wallis.

Hungry for reward: How can neuroscience inform the development of treatment for Anorexia Nervosa?

Dysfunctional reward from the pursuit of thinness presents a major challenge to recovery from Anorexia Nervosa (AN). We explore the neuroscientific basis of aberrant reward in AN, with the aim of generating novel hypotheses for translational investigation, and elucidate disease mechanisms to inform the development of targeted interventions. Relevant neuroimaging and behavioural studies are reviewed. These suggest that altered eating in AN may be a consequence of aberrant reward processing combined with exaggerated cognitive control. We consider evidence that such aberrant reward processing is reflected in the compulsive behaviours characterising AN, with substantial overlap in the neural circuits implicated in reward processing and compulsivity. Drawing on contemporary neuroscientific theories of substance dependence, processes underpinning the shift from the initially rewarding pursuit of thinness to extreme and compulsive weight control behaviours are discussed. It is suggested that in AN, weight loss behaviour begins as overtly rewarding, goal-directed and positively reinforced, but over time becomes habitual and increasingly negatively reinforced. Excessive habit formation is suggested as one underlying mechanism perpetuating compulsive behaviour. Ongoing research into the behavioural and neural basis of aberrant reward in AN is required to further elucidate mechanisms. We discuss clinical and transdiagnostic implications, and propose that future treatment innovation may benefit from the development of novel interventions targeting aberrant reward processing in AN.

The ethics of neuromodulation for anorexia nervosa: a focus on rTMS

OBJECTIVE

Recently there has been emerging clinical and research interest in the application of deep brain stimulation (DBS) and repetitive transcranial magnetic stimulation (rTMS) to the treatment of anorexia nervosa (AN). To our knowledge, few studies have discussed ethical aspects associated with the increased use of neuromodulation in AN, some of which are quite specific to AN, despite the rapid development and dissemination of these new technologies.

METHOD

We provide a brief overview of three published rTMS studies for AN and discuss ethical issues involved in the use of neuromodulation for AN.

RESULTS

In contrast to neurosurgery or DBS, rTMS is a less invasive technique, with less associated risk, and thus has greater potential to become a more widespread augmentation or add-on therapy for AN. New therapeutic procedures are promising, yet they raise ethical questions regarding informed consent and patient selection. Illness-specific issues surrounding authenticity and autonomy are important to consider, ensuring an ethical approach to treatment for patients with AN.

DISCUSSION

We argue that ethical investigations for neuromodulation techniques are timely and important, and discussions should go beyond the immediate goals of patient safety, consent, and risk and benefit, to consider broader ethical concepts such as authenticity and autonomy.

La neuromodulation est-elle une technique d’avenir dans la prise en charge des troubles des conduites alimentaires (TCA) ?

Les techniques de neuromodulation sont de plus en plus utilisées en psychiatrie. Dans le contexte des troubles des conduites alimentaires (TCA) où peu de prises en charge efficaces sont disponibles, plusieurs de ces techniques pourraient avoir un intérêt pour mieux appréhender la physiopathologie et/ou comme thérapie innovante. Trois techniques émergent. Deux sont des techniques de neuromodulation non invasives : la repetitive Transcranial Magnetic Stimulation (rTMS) et la transcranial Direct-Current Stimulation (tDCS) et une nécessite une intervention chirurgicale : la stimulation cérébrale profonde. Dans la boulimie, plusieurs études versus placebo utilisant la rTMS ont montré une diminution des pulsions alimentaires sur du court terme. Nos résultats préliminaires dans une étude multicentrique suggèrent une diminution du nombre de crises dans les 15 jours post-rTMS. La rTMS dans cette population est bien tolérée. Une série d’études pilote suggère également que la tDCS diminue les pulsions et les prises alimentaires et améliore des fonctions cognitives perturbées dans les TCA. Dans l’anorexie, la tolérance de la rTMS a été montrée comme bonne, même chez des patientes à poids très bas. Plusieurs études sont actuellement en cours pour évaluer l’effet sur des fonctions-clés de l’anorexie comme la perception corporelle ou la conscience intéroceptive avec pour objectif essentiel de mieux cerner la physiopathologie. Mais la technique de neuromodulation qui offre le plus d’espoir est la stimulation cérébrale profonde. Deux études pilotes récentes chez des patientes anorexiques très sévères suggèrent non seulement une bonne tolérance mais aussi une amélioration très nette de la symptomatologie alimentaire dans les mois ayant suivi l’intervention. Néanmoins, ces études restent à répliquer et les meilleurs sites et protocoles de stimulation restent à définir. Ainsi, ces techniques suscitent beaucoup d’espoir dans des pathologies résistantes mais leurs efficacités potentielles et utilisation clinique restent encore à définir.

Neuromodulation for eating disorders: obesity and anorexia

Extremes of eating disorders (ED) have become prevalent in both developed and developing countries. Available therapies, though largely effective, fail in a substantial number of patients and carry considerable side effects. Morbid obesity and anorexia nervosa (AN) represent important causes of morbidity and mortality among young adults. Morbid obesity affects disproportionate numbers of children. AN is also important for its high mortality in young adults. The challenges of effectively treating AN are well recognized. In this article, important aspects of ED are reviewed in detail and novel approaches to the treatment of ED are proposed.