Does compulsive behavior in Anorexia Nervosa resemble an addiction? A qualitative investigation

From compulsivity to compulsion: the neural basis of compulsive disorders

Compulsive behaviour, an apparently irrational perseveration in often maladaptive acts, is a potential transdiagnostic symptom of several neuropsychiatric disorders, including obsessive-compulsive disorder and addiction, and may reflect the severe manifestation of a dimensional trait termed compulsivity. In this Review, we examine the psychological basis of compulsions and compulsivity and their underlying neural circuitry using evidence from human neuroimaging and animal models. Several main elements of this circuitry are identified, focused on fronto-striatal systems implicated in goal-directed behaviour and habits. These systems include the orbitofrontal, prefrontal, anterior cingulate and insular cortices and their connections with the basal ganglia as well as sensoriomotor and parietal cortices and cerebellum. We also consider the implications for future classification of impulsive-compulsive disorders and their treatment.

Living and leaving a life of coercion: a qualitative interview study of patients with anorexia nervosa and multiple involuntary treatment events

BACKGROUND

A small but significant group of patients with anorexia nervosa (AN) undergo multiple involuntary treatment (IT) events. To enhance our understanding of IT and potentially inform treatment, we explored experiences and perspectives on IT of these patients.

METHODS

We designed a qualitative semi-structured interview study and used reflexive thematic analysis. Participants were at least 18 years of age, had multiple past IT events (≥ 5) related to AN over a period of at least one month of which the last IT event happened within the preceding five years. Participants had no current IT, intellectual disability, acute psychosis, or severe developmental disorder. We adopted an inductive approach and constructed meaning-based themes.

RESULTS

We interviewed seven participants. The data portrayed a process of living and leaving a life of coercion with a timeline covering three broad themes: living with internal coercion, coercive treatment, and leaving coercion; and five subthemes: helping an internal battle, augmenting suffering, feeling trapped, a lasting imprint, and changing perspectives. We highlighted that patients with AN and multiple IT events usually experienced internal coercion from the AN prior to external coercion from the health care system. IT evoked significant negative affect when experienced, and often left an adverse imprint. Moreover, IT could help an internal battle against AN and perspectives on IT could change over time.

CONCLUSIONS

Our study suggests that feeling internally coerced by AN itself sets the stage for IT. Clinicians should be conscious of the potential iatrogenic effects of IT, and reserve IT for potentially life-threatening situations.

Hooked on weight control: An economic theory of anorexia nervosa and its impact on health and longevity

In this paper, I integrate a theory of body image, weight control, and addiction in a life cycle model with health deficit accumulation in order to explain the phenomenon of anorexia nervosa and its impact on health and longevity. Individuals consume normal goods and foods and can work off excess calories with physical exercise. There exists a healthy body mass index and deviations from it increasingly cause health deficits due to obesity or underweight. There exists also a subjective target weight and being heavier than target weight causes a loss of utility from body image. Anorexia is initiated in individuals who are particularly successful in weight control and prone to addiction. Addiction to weight control motivates anorexic individuals to perpetually adjust their target weight downwards and to eat less and exercise more. With declining weight, health deficits accumulate faster and mortality risk rises. I calibrate the model to an average American woman with bmi 28. Due to weight loss addiction, the bmi declines to a level of 15 and causes an expected loss of 15 years of life. I also discuss potential therapies and recovery from the disease.

Learned industriousness as a translational mechanism in anorexia nervosa

It remains unexplained why some behaviours persist despite being non-hedonic and ostensibly aversive. This phenomenon is especially baffling when such behaviours are taken to excess in the form of psychopathology. Anorexia nervosa is one psychiatric disorder in which effortful behaviours that most people find unpleasant (suchas restrictive eating) are persistently performed. We propose thatthe social psychology theory of learned industriousness providesa novel mechanistic account for such phenomena. This theoryposits that high-effort behaviour can be conditioned to acquire secondary reinforcing properties through repeated pairing with reward. Accordingly, effort sensations become less aversive andmore appetitive, increasing willingness to engage in effortful behaviour. In this Perspective, we review pre-clinical behaviouraland biological data that support learned industriousness, contrast learned industriousness with other models of non-hedonic persistence (such as habit learning), highlight evidence that supports learned industriousness in individuals with anorexia nervosa and consider implications of the model, including translation to other psychiatric presentations.

Why do we climb mountains? An exploration of features of behavioural addiction in mountaineering and the association with stress-related psychiatric disorders

Common knowledge implies that individuals engaging in outdoor sports and especially in regular and extreme mountaineering are exceptionally healthy and hardened. Physical activity in outdoor environments has a positive effect on physical and mental health. However, regular and/or extreme mountaineering might share similarities with behavioural addictions and could thus also have a negative impact on health. In this cross-sectional web-based questionnaire study, we collected data on exercise and mountaineering addiction (Exercise Addiction Inventory; original and adapted version for mountaineering; Exercise Dependence Scale adapted version for mountaineering). Further surveyed parameters included mountaineering habits, Risk-Taking Inventory, Sensation-Seeking/Emotion Regulation/Agency Scale (SEAS), resilience, self-perceived stress, physical activity in metabolic units and mental health. Comparisons were performed between individuals with symptoms of addiction to mountaineering (MA) and individuals without symptoms of addiction to mountaineering or sports in general (CO) using non-parametric analyses. We analysed data from 335 participants, n = 88 thereof with addiction to mountaineering (MA) and n = 247 control participants (CO). The MA group scored significantly higher with regards to self-perceived stress (p < 0.001) and included a significantly higher number of individuals affected by symptoms of depression (p < 0.001), symptoms of anxiety (p < 0.001), symptoms of eating disorders (p < 0.001), alcohol abuse or dependence (p < 0.001), illicit drug abuse (p = 0.050), or current and history of psychiatric disorders (p < 0.001). Individuals with MA showed higher values in all SEAS subscales as well as increased risk-taking (p < 0.001). Regular and extreme mountaineering can display features of a behavioural addiction and is associated with psychiatric disorders. Behavioural addiction in mountaineering is associated with higher levels of sensation-seeking, emotion regulation, and agency, as well as increased risk-taking.

Paraventricular hypothalamic vasopressin neurons induce self-grooming in mice

Self-grooming plays an essential role in hygiene maintenance, thermoregulation, and stress response. However, the neural populations involved in self-grooming remain largely unknown. The paraventricular hypothalamic nucleus (PVH) has been implicated in the regulation of self-grooming. Arginine vasopressin-producing neurons are among the major neuronal populations in the PVH (PVH^AVP), which play important roles in water homeostasis, blood pressure regulation, feeding, and stress response. Here, we report the critical role of PVH^AVP neurons in the induction of self-grooming. Optogenetic activation of PVH^AVP neurons immediately induced self-grooming in freely moving mice. Chemogenetic activation of these neurons also increased time spent self-grooming. In contrast, their chemogenetic inhibition significantly reduced naturally occurring self-grooming, suggesting that PVH^AVP-induced grooming has physiological relevance. Notably, optogenetic activation of PVH^AVP neurons triggered self-grooming over other adaptive behaviors, such as voracious feeding induced by fasting and social interaction with female mice. Thus, our study proposes the novel role of PVH^AVP neurons in regulating self-grooming behavior and, consequently, hygiene maintenance and stress response. Furthermore, uncontrolled activation of these neurons may be potentially relevant to diseases characterized by compulsive behaviors and impaired social interaction, such as autism, obsessive–compulsive disorder, and anorexia nervosa.

Deep Brain Stimulation of the Nucleus Accumbens in Severe Enduring Anorexia Nervosa: A Pilot Study

Introduction

Anorexia nervosa (AN) is one of the most debilitating psychiatric disorders, becoming severe and enduring in a third of cases; with few effective treatments. Deep brain stimulation is a reversible, adjustable neurosurgical procedure that has been gaining ground in psychiatry as a treatment for depression and obsessive-compulsive disorder, yet few studies have investigated AN. Abnormal eating behavior and the compulsive pursuit of thinness in AN is, in part, a consequence of dysfunction in reward circuitry and the nucleus accumbens (NAcc) is central to reward processing.

Methods

Phase 1 prospective open-label pilot study of seven individuals with severe enduring AN. Electrodes were implanted bilaterally into the NAcc with stimulation at the anterior limb of the internal capsule using rechargeable implantable pulse generators. The protocol of 15 months included 12 months of deep brain stimulation incorporating two consecutive, randomized blind on-off fortnights 9 months after stimulation onset. The primary objectives were to investigate safety and feasibility, together with changes in eating disorder psychopathology.

Results

Feasibility and safety was demonstrated with no serious adverse events due to deep brain stimulation. Three patients responded to treatment [defined as > 35% reduction in Eating Disorders Examination (EDE) score at 12 months] and four patients were non-responders. Responders had a statistically significant mean reduction in EDE scores (50.3% reduction; 95% CI 2.6-98.2%), Clinical Impairment Assessment (45.6% reduction; 95% CI 7.4-83.7%). Responders also had a statistically significant mean reduction in Hamilton Depression Scale, Hamilton Anxiety Scale and Snaith-Hamilton pleasure scale. There were no statistically significant changes in Body Mass Index, Yale-Brown-Cornell Eating Disorder Scale, Yale-Brown Obsessive-Compulsive Scale and World Health Organization Quality of Life Psychological subscale.

Conclusion

This study provides some preliminary indication that deep brain stimulation to the NAcc. Might potentially improve some key features of enduring AN. In this small study, the three responders had comorbid obsessive-compulsive disorder which predated AN diagnosis. Future studies should aim to further elucidate predictors of outcome.

Clinical Trial Registration

[www.ClinicalTrials.gov], identifier [Project ID 128658].

Obsessive-compulsive symptoms in young women affected with anorexia nervosa, and their relationship with personality, psychopathology, and attachment style

PURPOSE

Obsessive-compulsive symptoms (OC) are associated with greater morbidity and worse prognosis in anorexia nervosa (AN). We assessed the presence of non-eating OC in participants with AN and related them with their psychopathology, personality, and attachment style features.

METHODS

Young women with AN (N = 41, 30 restrictor and 11 binge-purging type) were assessed on the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). These participants with AN and 82 healthy controls (HC) completed the Temperament and Character Inventory (TCI), Eating Disorder Inventory-2 (EDI-2), Symptom Checklist-90 (SCL-90), Toronto Alexithymia Scale (TAS-20), and Attachment Style Questionnaire (ASQ). The association between Y-BOCS scores and indexes of psychopathology, personality, and attachment were examined.

RESULTS

AN had significantly higher scores than HC on the EDI-2, SCL-90, TAS-20, ASQ-Need for Approval, and TCI-Harm Avoidance and Self-directedness. The Y-BOCS scores were significantly correlated with ASQ-Need for Approval, TAS-20-Difficulty in Describing Feelings, SCL-90-Phobic Anxiety, and Anxiety, EDI-2-Drive to Thinness, and Asceticism. Need for Approval displayed the strongest correlation with OC symptoms. Difficulty in describing feelings displayed the strongest correlation with compulsive OC symptoms.

CONCLUSIONS

OC traits in AN were primarily associated with measures of insecure attachment rather than to their eating disorder or general psychopathology. Therapeutic approaches to correcting insecure attachment may be considered as a possible approach to treating AN patients with OC. The study supports a new psychopathological perspective for understanding the meaning of OC symptoms in AN.

LEVEL OF EVIDENCE

III: Evidence obtained from cohort or case-control analytic studies.

'In an otherwise limitless world, I was sure of my limit.'† Experiencing Anorexia Nervosa: A phenomenological metasynthesis

Anorexia Nervosa (AN) has the highest mortality rate of the mental disorders, with still less than 50% of affected individuals achieving recovery. Recent calls to bring innovative, empirical research strategies to the understanding of illness and its core psychopathological features highlight the need to address significant paucity of efficacious treatment. The current study brings a phenomenological approach to this challenge, synthesizing lived experience phenomena as described by qualitative literature. Fifty-three studies published between the years 1998 and 2021 comprising a total of 1557 participants aged 12-66 suffering from AN or sub-threshold AN are included. Reciprocal and refutational analysis generated six key third-order constructs: "emotion experienced as overwhelming," "identity," "AN as a tool," "internal conflict relating to Anorexia," "interpersonal communication difficulties" and "corporeality." Twenty-six sub-themes were identified, the most common being fear, avoidance, AN as guardian/protector, and AN as intertwined with identity. Some themes associated with current treatment models such as low self-esteem, need for social approval and feelings of fatness were less common. We highlight the significant role of intense and confusing emotion in AN, which is both rooted in and engenders amplified fear and anxiety. Restrictive eating functions to numb these feelings and withdraw an individual from a chaotic and threatening world whilst providing a sense of self around which to build an illness identity. Results have implications for therapeutic practice and overly protective weight and shape focused medical treatment models, which may serve to reinforce the disease.

The influence of homeostatic mechanisms on neural regulation of food craving in anorexia nervosa

BACKGROUND

Restrictive food intake in anorexia nervosa (AN) has been related to an overactive cognitive control network inhibiting intuitive motivational responses to food stimuli. However, the influence of short-term homeostatic signaling on the neural regulation of cue-induced food craving in AN is still unclear.

METHODS

Twenty-five women with AN and 25 matched normal-weight women were examined on two occasions after receiving either glucose or water directly into their stomach using a nasogastric tube. Participants were blinded to the type of infusion. An event-related functional magnetic resonance imaging paradigm was used to investigate the effect of intestinal glucose load on neural processing during either simple viewing or distraction from food stimuli.

RESULTS

Neural differences between patients with AN and normal-weight participants were found during the distraction from food stimuli, but not during the viewing condition. When compared to controls, patients with AN displayed increased activation during food distraction in the left parietal lobule/precuneus and fusiform gyrus after water infusion and decreased activation in ventromedial prefrontal and cingulate regions after intestinal glucose load.

CONCLUSIONS

Independent of the cephalic phase and the awareness of caloric intake, homeostatic influences trigger disorder-specific reactions in AN. Food distraction in patients with AN is associated with either excessive higher-order cognitive control during physiological hunger or decreased internally directed attention after intestinal glucose load. These findings suggest that food distraction plays an important role in the psychopathology of AN. This study was registered on clinicaltrials.gov with identifier: NCT03075371.

Physical activity behaviors and attitudes among women with an eating disorder: a qualitative study

BACKGROUND

Physical activity (PA) is an integral part of healthcare for the general population and individuals with psychiatric disorders. However, PA is significantly more complex for and related to both healthy (e.g., reduced anxiety and depressive symptoms) and unhealthy outcomes (e.g., intrusive, repetitive thoughts that lead to abnormally high levels of PA) among women with an eating disorder (ED). Consequently, many healthcare professionals recommend abstinence from PA during ED treatment. Despite this, women may remain engaged in PA during ED treatment or resume PA shortly thereafter. Little has been done to understand women's PA behaviors and attitudes and to explore how they integrate PA into their lives during and after ED treatment. Thus, this study sought to explore PA behaviors and attitudes among women with an ED.

METHODS

Nine women who self-reported receiving an ED diagnosis participated in semi-structured interviews, which were transcribed and analysed thematically.

RESULTS

Six interrelated themes were constructed to represent participants' PA experiences: PA as a lifestyle, PA can be beneficial, How I feel when I can't do PA, Being cautious about PA, Reactions to healthcare professionals' practice of recommending abstinence from PA during ED treatment, and PA programming thoughts.

CONCLUSIONS

Overcoming dysfunctional PA behaviors (e.g., engaging in abnormally high levels of PA) and attitudes (e.g., associating PA with caloric expenditure) can be a long and complicated journey for women with an ED. Nevertheless, women with an ED want PA to be integrated into their ED treatment protocol for two key reasons, namely to accrue the benefits associated with PA and to learn how to engage in PA in adaptive and healthy ways.

Descriptions of Disordered Eating in German Psychiatric Textbooks, 1803-2017

The most common eating disorders (EDs) according to DSM-5 are anorexia nervosa (AN), bulimia nervosa (BN) and binge eating disorder (BED). These disorders have received increasing attention in psychiatry due to rising prevalence and high morbidity and mortality. The diagnostic category "anorexia nervosa," introduced by Ernest-Charles Lasègue and William Gull in 1873, first appears a century later in a German textbook of psychiatry, authored by Gerd Huber in 1974. However, disordered eating behavior has been described and discussed in German psychiatric textbooks throughout the past 200 years. We reviewed content regarding eating disorder diagnoses but also descriptions of disordered eating behavior in general. As material, we carefully selected eighteen German-language textbooks of psychiatry across the period 1803-2017. Previously, in German psychiatry, disordered eating behaviors were seen as symptoms of depressive disorders, bipolar disorder or schizophrenia, or as manifestations of historical diagnoses no longer used by the majority of psychiatrists such as neurasthenia, hypochondria and hysteria. Interestingly, 19th and early 20th century psychiatrists like Kraepelin, Bumke, Hoff, Bleuler, and Jaspers reported symptom clusters such as food refusal and vomiting under these outdated diagnostic categories, whereas nowadays they are listed as core criteria for specific eating disorder subtypes. A wide range of medical conditions such as endocrinopathies, intestinal or brain lesions were also cited as causes of abnormal food intake and body weight. An additional consideration in the delayed adoption of eating disorder diagnoses in German psychiatry is that people with EDs are commonly treated in the specialty discipline of psychosomatic medicine, introduced in Germany after World War II, rather than in psychiatry. Viewed from today's perspective, the classification of disorders associated with disordered eating is continuously evolving. Major depressive disorder, schizophrenia and physical diseases have been enduringly associated with abnormal eating behavior and are listed as important differential diagnoses of EDs in DSM-5. Moreover, there are overlaps regarding the neurobiological basis and psychological and psychopharmacological therapies applied to all of these disorders.

FOOD ADDICTION AS A PROXY FOR ANOREXIA NERVOSA SEVERITY: NEW DATA BASED ON THE YALE FOOD ADDICTION SCALE 2.0

The contribution of an addictive process to anorexia nervosa (AN) is an area of growing interest. Yet, little is known about how the food addiction concept (FA) may be of interest in understanding AN. This study investigates prevalence of FA diagnostic and its association with markers of severity in individuals with AN. We conducted a retrospective study in a sample of 73 patients with AN. We assessed FA with the Yale Food Addiction Scale 2.0, depressive and anxiety disorders, impulsivity (Beck Depression Inventory, STAI, BIS-11) and eating behavior (BITE, EDE-Q). Prevalence of FA in our sample was 47%. FA was significantly associated and positively correlated with the binge-eating/purging subtype of AN, higher levels of depression, anxiety and greater eating psychopathology. FA was not associated with level of impulsivity nor leptin and IGF-1 blood levels. The relationship between FA severity and AN severity was mediated by the severity of binge eating behaviors. Our results suggest that the presence of FA may represent a more severe variant of AN. Longitudinal studies are needed to better understand the etiologic process between FA and AN.

Predicting the restrictive eating, exercise, and weight monitoring compulsions of anorexia nervosa

PURPOSE

Compulsions surrounding restrictive eating, exercise, and weight monitoring are thought to maintain abnormal eating behaviour in individuals with anorexia nervosa (AN). This study aimed to determine if AN psychopathology and trait anxiety explain the presence of restrictive eating, exercise, and weight monitoring compulsions in a mixed sample.

METHODS

Participants were 31 females with AN and 31 age and gender-matched healthy individuals (HC). Restrictive eating, exercise and weight monitoring compulsion presence was compared between AN and HC groups. Multivariable poisson regression analyses, adjusted for diagnostic status, were conducted to assess the association of both AN psychopathology and trait anxiety with compulsions across the mixed group.

RESULTS

Individuals with AN endorsed a greater number of restrictive eating, exercise and weight monitoring compulsions compared to HC. In adjusted poisson regression analyses neither AN psychopathology nor trait anxiety predicted compulsion presence: incidence rate ratio (IRR) for AN psychopathology = 1.15 [95% CI 0.84, 1.57], p = 0.39; IRR for trait anxiety = 1.01 [95% CI 0.97, 1.06], p = 0.50.

CONCLUSIONS

Greater presence of restrictive eating, exercise and weight monitoring compulsions was reported by individuals with AN, supporting the conceptualisation of disorder behaviours as compulsive. The study was underpowered to robustly evaluate the association between predictors of interest and the compulsions outcome, largely owing to the small sample size. Further investigation is required, ideally using methods able to identify causal and mediation effects.

LEVEL OF EVIDENCE

Level V, cross-sectional study.

Bad Things Come to Those Who Do Not Wait: Temporal Discounting Is Associated With Compulsive Overeating, Eating Disorder Psychopathology and Food Addiction

The tendency to act on immediate pleasure-driven desires, due to the devaluation of future rewards [a process known as temporal discounting (TD)], has been associated with substance use disorders (SUD) and with conditions characterised by compulsive overeating. The study involved a large inclusive participant sample (i.e., no diagnostic or exclusion criteria were applied). They were recruited/assessed online and we investigated whether TD was related to compulsive overeating and associated problems. Participants [N = 432, (48 males)] completed an online survey, which included a hypothetical monetary TD task, the Eating Disorder Examination-Questionnaire (EDE-Q), the Yale Food Addiction Scale (YFAS) and the Depression Anxiety and Stress Scales (DASS). TD correlated with frequency of compulsive overeating and compensatory behaviours, with eating disorder psychopathology, with scores on the YFAS, and with body mass index (BMI). As our study shows that elevated rates of TD are associated with a range of behaviours/measures, we propose that it is more likely that elevated TD rates are a predisposing factor rather than a consequence of the behaviour, i.e., elevated rates of TD contribute to pathological eating-related behaviours; however, a bi-directional explanation is also possible. Future research should investigate whether interventions aimed at reducing TD have clinical potential for treating problematic eating behaviours.

A Metabolic Perspective on Reward Abnormalities in Anorexia Nervosa

Anorexia nervosa (AN) is the psychiatric disorder with the highest mortality rate; however, the mechanisms responsible for its pathogenesis remain largely unknown. Large-scale genome-wide association studies (GWAS) have identified genetic loci associated with metabolic features in AN. Metabolic alterations that occur in AN have been mostly considered as consequences of the chronic undernutrition state but until recently have not been linked to the etiology of the disorder. We review the molecular basis of AN based on human genetics, with an emphasis on the molecular components controlling energy homeostasis, highlight the main metabolic and endocrine alterations occurring in AN, and decipher the possible connection between metabolic factors and abnormalities of reward processes that are central in AN.

Controlling the laxative abuse of anorexia nervosa patients with the Serigaya Methamphetamine Relapse Prevention Program workbook: a case report

Background

There is no consensus on effective treatment for laxative abuse in patients with eating disorders. Here, we report the case of a patient with laxative abuse who showed some improvement through an intervention based on the Matrix model.

Case presentation

A woman diagnosed with anorexia nervosa-binge eating/purging type (AN-BP) steadfastly denied laxative abuse and would not admit to suffering from an eating disorder. This led to low motivation for undergoing conventional psychotherapy, psychoeducation, and cognitive behavioral therapy. These were ineffective and followed by repeated cycles of hospitalization and discharge. The patient’s general condition, as depicted by her laboratory and clinical parameters, deteriorated due to the medical complications resulting from laxative abuse.

Focusing on laxative abuse, we considered an intervention for drug addiction. Because the patient could maintain a diet diary and acknowledged laxative abuse as a drug addiction, we introduced the Serigaya Methamphetamine Relapse Prevention Program (SMARPP) workbook as a self-administered treatment. The patient meticulously completed the treatment and experienced a gradual improvement in laxative abuse. She has not been re-hospitalized in 4 years, currently performs household chores, and demonstrates improved social function.

Conclusions

In patients with AN-BP, the SMARPP workbook may be effective in treating laxative abuse.

Study Protocol: Using Deep-Brain Stimulation, Multimodal Neuroimaging and Neuroethics to Understand and Treat Severe Enduring Anorexia Nervosa

BACKGROUND

Research suggests that altered eating and the pursuit of thinness in anorexia nervosa (AN) are, in part, a consequence of aberrant reward circuitry. The neural circuits involved in reward processing and compulsivity overlap significantly, and this has been suggested as a transdiagnostic factor underpinning obsessive compulsive disorder, addictions and eating disorders. The nucleus accumbens (NAcc) is central to both reward processing and compulsivity. In previous studies, deep-brain stimulation (DBS) to the NAcc has been shown to result in neural and symptomatic improvement in both obsessive compulsive disorder and addictions. Moreover, in rats, DBS to the NAcc medial shell increases food intake. We hypothesise that this treatment may be of benefit in severe and enduring anorexia nervosa (SE-AN), but first, feasibility and ethical standards need to be established. The aims of this study are as follows: (1) to provide feasibility and preliminary efficacy data on DBS to the NAcc as a treatment for SE-AN; (2) to assess any subsequent neural changes and (3) to develop a neuroethical gold standard to guide applications of this treatment.

METHOD

This is a longitudinal study of six individuals with SE-AN of >7 years. It includes an integrated neuroethical sub-study. DBS will be applied to the NAcc and we will track the mechanisms underpinning AN using magnetoelectroencephalography, neuropsychological and behavioural measures. Serial measures will be taken on each intensively studied patient, pre- and post-DBS system insertion. This will allow elucidation of the processes involved in symptomatic change over a 15-month period, which includes a double-blind crossover phase of stimulator on/off.

DISCUSSION

Novel, empirical treatments for SE-AN are urgently required due to high morbidity and mortality costs. If feasible and effective, DBS to the NAcc could be game-changing in the management of this condition. A neuroethical gold standard is crucial to optimally underpin such treatment development.

CLINICAL TRIAL REGISTRATION

The study is ongoing and registered with www.ClinicalTrials.gov, https://clinicaltrials.gov/ct2/show/NCT01924598, 22 July, 2013. It has full ethical and HRA approval (Project ID 128658).

How extreme dieting becomes compulsive: A novel hypothesis for the role of anxiety in the development and maintenance of anorexia nervosa

The US National Institute of Mental Health's Research Domain Criteria (NIMH RDoC) advocates the study of features common to psychiatric conditions. This transdiagnostic approach has recently been adopted into the study of anorexia nervosa (AN), an illness that can be considered compulsive in nature. This has led to the development of an account of AN that identifies key roles for the heightened reinforcement of starvation, leading to its excessive repetition, and goal-directed system dysfunction. Considering models of illness in other compulsive disorders, we extend the existing account to explain the emergence of reinforcement and goal-directed system abnormalities in AN, proposing that anxiety is central to both processes. As such we emphasise the particular importance of the anxiolytic effects of starvation, over other reinforcing outcomes, in encouraging the continuation of starvation within a model that proposes a number of mechanisms by which anxiety operates in the development and maintenance of AN. We suggest the psychopathology of AN mediates the relationship between the anxiolytic effects of starvation and excessive repetition of starvation, and that compulsive starvation has reciprocal effects on its determinants. We thus account for the emergence of symptoms of AN other than compulsive starvation, and for the relationship between different features of the disorder. By extending and adapting an existing explanation of AN, we provide a richer aetiological model that invites new research questions and could inform novel approaches to prevention and treatment.

Facets of Impulsivity and Compulsivity in Women with Anorexia Nervosa

This study sought to investigate independent associations of impulsivity and compulsivity with eating disorder (ED) symptoms. Women (N = 81) with full or subthreshold Diagnostic and Statistical Manual of Mental Disorders IV anorexia nervosa (AN) completed a semi-structured interview and self-report questionnaires. Multiple regression analyses were conducted using ED symptoms as dependent variables and facets of impulsivity and compulsivity as predictor variables (controlling for body mass index and AN diagnostic subtype). For impulsivity facets, lack of perseverance was uniquely associated with eating concern, shape concern and restraint, whereas negative urgency was uniquely associated with eating concern and frequency of loss of control eating; neither sensation seeking nor lack of premeditation was uniquely associated with any ED variables. Compulsivity was uniquely associated with restraint, eating concern and weight concern. Results support independent associations of impulsivity and compulsivity with ED symptoms in adults with AN, suggesting potential utility in addressing both impulsive and compulsive processes in treatment. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association.

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.

Differential activation of the frontal pole to high vs low calorie foods: The neural basis of food preference in Anorexia Nervosa?

Neuroimaging studies in anorexia nervosa (AN) suggest that altered food reward processing may result from dysfunction in both limbic reward and cortical control centers of the brain. This fMRI study aimed to index the neural correlates of food reward in a subsample of individuals with restrictive AN: twelve currently ill, fourteen recovered individuals and sixteen healthy controls. Participants were shown pictures of high and low-calorie foods and asked to evaluate how much they wanted to eat each one following a four hour fast. Whole-brain task-activated analysis was followed by psychophysiological interaction analysis (PPI) of the amygdala and caudate. In the AN group, we observed a differential pattern of activation in the lateral frontal pole: increasing following presentation of high-calorie stimuli and decreasing in during presentation of low-calorie food pictures, the opposite of which was seen in the healthy control (HC) group. In addition, decreased activation to food pictures was observed in somatosensory regions in the AN group. PPI analyses suggested hypo-connectivity in reward pathways, and between the caudate and both somatosensory and visual processing regions in the AN group. No significant between-group differences were observed between the recovered group and the currently ill and healthy controls in the PPI analysis. Taken together, these findings further our understanding of the neural processes which may underpin the avoidance of high-calorie foods in those with AN and might exacerbate the development of compulsive weight-loss behavior, despite emaciation.

An investigation of habit learning in Anorexia Nervosa

Anorexia Nervosa (AN) is a disorder characterised by compulsive behaviour, such as self-starvation and excessive exercise, which develop in the pursuit of weight-loss. Recent theory suggests that once established, compulsive weight-loss behaviours in AN may become habitual. In two parallel studies, we measured whether individuals with AN showed a bias toward habits using two outcome-devaluation tasks. In Study 1, 23 women with AN (restrictive and binge/purge subtypes), and 18 healthy controls (HC) completed the slips-of-action paradigm, designed to assess reward-based habits. In Study 2, 13 women with restrictive AN, 14 women recovered from restrictive AN, and 17 female HC participants completed the slips-of-action paradigm, and an avoidance paradigm, designed to assess aversive habits. AN participants showed no deficit relative to HCs in the ability to use feedback to respond correctly to stimuli. Following devaluation of outcomes, all groups in both studies were equally able to withhold inappropriate responses, suggesting no deficit in the balance between goal-directed and habitual control of behaviour in these tasks in AN. These results suggest that individuals with AN do not show a generalised tendency to rely on habits in two outcome-devaluation tasks. Future research is needed to investigate the potential role of disorder-specific habits in the maintenance of behaviour in AN.