Rebecca J. Park

Rumination, experiential avoidance, and dysfunctional thinking in eating disorders.

The majority of research in eating disorders (ED) has investigated the content of disorder-specific thoughts, while few studies have addressed underlying cognitive-affective processes. A better understanding of processes underpinning ED may have important implications for treatment development. Two studies were conducted that investigated levels of rumination, beliefs about rumination, experiential avoidance, and aspects of schematic thinking in individuals with eating pathology. The latter was assessed with a newly designed ED-Sentence Completion Task (ED-SCT). Study 1 (N = 177) examined relations between ED psychopathology and these variables in a student population. Extending this, Study 2 (N = 26) assessed differences between patients with anorexia nervosa and healthy control participants. The results showed that ED psychopathology was related to disorder-specific cognitions, experiential avoidance as well as ruminative brooding but not reflection. A follow-up of anorexia nervosa patients indicated that changes in ED psychopathology were associated with changes in dysfunctional attitudes and maladaptive cognitive-affective processes. These findings highlight cognitive processes that may play an important role in the maintenance of eating pathology.

Atypical antipsychotics and anorexia nervosa: A review

BACKGROUND There is currently mixed opinion regarding the value of using atypical antipsychotics to treat anorexia nervosa (AN). AIMS To evaluate the literature on the use of atypical antipsychotics in AN. METHOD A review of all studies and clinical guidelines published before September 2009 involving use of an atypical antipsychotic in patients with AN. Analysis is by narrative synthesis. RESULTS Forty-three publications or study protocols were found, including four randomized-controlled trials, five open-label trials and 26 case reports. The most studied drugs were olanzapine, quetiapine and risperidone. Atypical antipsychotics appear safe and there is some evidence of positive effects on depression, anxiety and core eating disordered psychopathology in patients with anorexia nervosa. Currently there is insufficient evidence to confirm atypical antipsychotics enhance weight gain in this setting. CONCLUSIONS Further high quality evidence is needed in this area in order to provide practical guidance to clinicians. However, the main challenge is to persuade adequate numbers of AN patients to participate in research trials.

Increased resting state functional connectivity in the default mode network in recovered anorexia nervosa.

Functional brain imaging studies have shown abnormal neural activity in individuals recovered from anorexia nervosa (AN) during both cognitive and emotional task paradigms. It has been suggested that this abnormal activity which persists into recovery might underpin the neurobiology of the disorder and constitute a neural biomarker for AN. However, no study to date has assessed functional changes in neural networks in the absence of task‐induced activity in those recovered from AN. Therefore, the aim of this study was to investigate whole brain resting state functional connectivity in nonmedicated women recovered from anorexia nervosa. Functional magnetic resonance imaging scans were obtained from 16 nonmedicated participants recovered from anorexia nervosa and 15 healthy control participants. Independent component analysis revealed functionally relevant resting state networks. Dual regression analysis revealed increased temporal correlation (coherence) in the default mode network (DMN) which is thought to be involved in self‐referential processing. Specifically, compared to healthy control participants the recovered anorexia nervosa participants showed increased temporal coherence between the DMN and the precuneus and the dorsolateral prefrontal cortex/inferior frontal gyrus. The findings support the view that dysfunction in resting state functional connectivity in regions involved in self‐referential processing and cognitive control might be a vulnerability marker for the development of anorexia nervosa. Hum Brain Mapp 35:483–491, 2014.

The role of experiential avoidance, rumination and mindfulness in eating disorders

Anorexia nervosa has been associated with high levels of ruminative thoughts about eating, shape and weight as well as avoidance of emotion and experience. This study examined the associations between disorder-specific rumination, mindfulness, experiential avoidance and eating disorder symptoms. A sample of healthy females (n=228) completed a battery of on-line self-report measures. A hierarchical regression analysis revealed that ruminative brooding on eating, weight and shape concerns was uniquely associated with eating disorder symptoms, above and beyond anxiety and depression symptoms. In a small group (n=42) of individuals with a history of anorexia nervosa, only reflection on eating weight and shape was able to predict eating disorder symptoms when controlling for depression and anxiety. The results suggest that rumination (both brooding and reflection) on eating, weight and shape concerns may be a process which exacerbates eating disorder symptoms. Examining rumination may improve understanding of the cognitive processes which underpin anorexia nervosa and this may in turn aid the development of novel strategies to augment existing interventions. Replication in a larger clinical sample is warranted.

Compulsivity in anorexia nervosa: a transdiagnostic concept

The compulsive nature of weight loss behaviors central to anorexia nervosa (AN), such as relentless self-starvation and over-exercise, has led to the suggestion of parallels between AN and other compulsive disorders such as obsessive–compulsive disorder (OCD) and addictions. There is a huge unmet need for effective treatments in AN, which has high rates of morbidity and the highest mortality rate of any psychiatric disorder, yet a grave paucity of effective treatments. Viewing compulsivity as a transdiagnostic concept, seen in various manifestations across disorders, may help delineate the mechanisms responsible for the persistence of AN, and aid treatment development. We explore models of compulsivity that suggest dysfunction in cortico-striatal circuitry underpins compulsive behavior, and consider evidence of aberrancies in this circuitry across disorders. Excessive habit formation is considered as a mechanism by which initially rewarding weight loss behavior in AN may become compulsive over time, and the complex balance between positive and negative reinforcement in this process is considered. The physiological effects of starvation in promoting compulsivity, positive reinforcement, and habit formation are also discussed. Further research in AN may benefit from a focus on processes potentially underlying the development of compulsivity, such as aberrant reward processing and habit formation. We discuss the implications of a transdiagnostic perspective on compulsivity, and how it may contribute to the development of novel treatments for AN.

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.

Neural responses to emotional faces in women recovered from anorexia nervosa.

Impairments in emotional processing have been associated with anorexia nervosa. However, it is unknown whether neural and behavioural differences in the processing of emotional stimuli persist following recovery. The aim of this study was to investigate the neural processing of emotional faces in individuals recovered from anorexia nervosa compared with healthy controls. Thirty-two participants (16 recovered anorexia nervosa, 16 healthy controls) underwent a functional magnetic resonance imaging (fMRI) scan. Participants viewed fearful and happy emotional faces and indicated the gender of the face presented. Whole brain analysis revealed no significant differences between the groups to the contrasts of fear versus happy and vice versa. Region of interest analysis demonstrated no significant differences in the neural response to happy or fearful stimuli between the groups in the amygdala or fusiform gyrus. These results suggest that processing of emotional faces may not be aberrant after recovery from anorexia nervosa.

Effects of analytical and experiential self-focus on stress-induced cognitive reactivity in eating disorder psychopathology

Previous research suggests distinct modes of self-focus, each with distinct functional properties: Analytical self-focus appears maladaptive, with experiential self-focus having more adaptive effects on indices of cognitive-affective functioning (e.g., Watkins, Moberly, & Moulds, 2008). The authors applied this framework to eating disorder (ED) psychopathology and manipulated the mode of self-focus prior to exposure to a stressor (imagining eating a large meal; Shafran, Teachman, Kerry, & Rachman, 1999). Study 1 showed that students high in ED psychopathology reported lower post-stressor feelings of weight or shape change and less subsequent attempts to neutralise (e.g., imagining exercising) after experiential relative to analytical self-focus. Study 2 found that partially weight restored patients with anorexia nervosa had lower post-stressor estimates of their own weight and reported lower urge to cancel stressor effects following experiential compared to analytical self-focus. Experiential self-focus was also followed by less neutralisation than analytical self-focus. Results suggest that the mode of self-focus affects cognitive reactivity following a stressor in individuals with ED psychopathology. Examining the mode within which individuals with ED psychopathology focus on self and body may raise important implications for understanding of psychopathology and open new possibilities for augmenting current treatments.

Assessing rumination in eating disorders: principal component analysis of a minimally modified ruminative response scale.

A process account of eating disorders (EDs) (Park et al., in press-a) proposes that preoccupation with ruminative themes of eating, weight and shape may be important in ED maintenance. No self-report measure exists to capture disorder-specific rumination in EDs. 275 healthy participants rated rumination items and completed self-report measures of ED symptoms, depression and anxiety. Principal component analysis revealed two factors, reflection and brooding. The final nine-item Ruminative Response Scale for Eating Disorders (RRS-ED) demonstrated good convergent and discriminant validity and test-retest reliability. The psychometric properties were replicated in an anorexia nervosa sample. The findings support the notion that rumination in EDs is distinct from rumination in depression and is not adequately captured by existing measures.

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.