Subliminal fear priming potentiates negative facial reactions to food pictures in women with anorexia nervosa

Momentary physiological indices related to eating disorders: A systematic and methodological review

Eating disorders (ED) are serious psychiatric illnesses, with no everyday support to intervene on the high rates of relapse. Understanding physiological indices that can be measured by wearable sensor technologies may provide new momentary interventions for individuals with ED. This systematic review, searching large databases, synthesises studies investigating peripheral physiological (PP) indices commonly included in wearable wristbands (heart rate [HR], heart rate variability [HRV], electrodermal activity [EDA], peripheral skin temperature [PST], and acceleration) in ED. Inclusion criteria included: (a) full peer-reviewed empirical articles in English; (b) human participants with active ED; and (c) containing one of five wearable physiological measures. Kmet risk of bias was assessed. Ninety-four studies were included (Anorexia nervosa [AN; N = 4418], bulimia nervosa [BN; N = 916], binge eating disorder [BED; N = 1604], other specified feeding and eating disorders [OSFED; N = 424], and transdiagnostic [N = 47]). Participants with AN displayed lower HR and EDA and higher HRV compared to healthy individuals. Those with BN showed higher HRV, and lower EDA and PST compared to healthy individuals. Other ED and Transdiagnostic samples showed mixed results. PP differences are indicated through various assessments in ED, which may suggest diagnostic associations, although more studies are needed to validate observed patterns. Results suggest important therapeutic potential for PP in ED, and larger studies including diverse participants and diagnostic groups are needed to fully uncover their role in ED.

Exploring the neurofunctional impairments and cognitive biases concerning food and body related stimuli in anorexia nervosa: An integrated EEG and eye-tracking study protocol

BACKGROUND

Patients with Anorexia Nervosa (AN) exhibit significant cognitive and neural disturbances compared to healthy individuals when processing food and body-related stimuli. These disturbances not only contribute to the manifestation and chronification of their pathological eating behaviour but also underscore the complex interplay of cognitive, emotional, and neurobiological factors in AN. However, the precise underlying cognitive and neural mechanisms of these disturbances remain a compelling area of investigation.

METHODS

This study presents a protocol developed for conducting a cross-sectional quasi-experimental study using a mixed model ANOVA approach with a crossover design. Our participants will consist of 20 patients with an active diagnosis of AN, 20 Overweight/obese individuals, and 20 Healthy Controls (HCs) with a normal BMI. An integrated eye-tracking and EEG methodology will be used in conjunction, with the primary aim of assessing participants' cognitive and neural processing towards high and low-calorie food stimuli. On an exploratory level, by utilizing the same methods, the present study will also investigate AN patients' responses towards high weight, normal weight, low weight, and self-body pictures, as well as towards images from the International Affective Picture System (IAPS) characterized by elevated valence and arousal levels. Additionally, behavioural methods such as yes or no questions, and self-reported questionnaires will be administered. The EEG and eye-tracking data will be analysed at early (50-300 ms) and late (350-500 ms) time intervals.

DISCUSSION

The investigation of the underlying cognitive and neural processes employed by patients with AN during the processing of food and body-related stimuli can help us develop a better understanding of the cognitive and neural mechanisms that contribute to the manifestation and maintenance of the disorder and assist in the development of more effective screening methods.

ETHICAL APPROVAL AND CONSENT TO PARTICIPATE

Ethical approval for the study has been obtained by the Cyprus National Bioethics Committee on 27.04.2023 (ΕΕΒΚ/ΕΠ/2023/19), and by the University of Cyprus (20.02.2023). Written informed consent will be obtained from all participants.

When is it good to feel bad? How sadness and fear differ in their effects on routine development

Introduction

This study follows recent calls to explore the emotional foundations of routine development. Routine development forms a nexus between stability and change and is thus crucial for studying organizational decision-making and organizational change. Individuals and teams going through organizational change often experience sadness and fear.

Methods

We conducted a laboratory experiment with 84 teams to study the effect of sadness and fear on routine development.

Results and discussion

In the sadness condition, we observed positive effects on repetitiveness, speed, reliability, and attentiveness in action. Teams experiencing fear reacted better to 'performance traps' in which pre-established routines are ineffective. Our findings show how the behaviors elicited by sadness and fear might ultimately affect team behavior, and therefore managerial practices.

Neural, physiological, and psychological markers of appetitive conditioning in anorexia nervosa: a study protocol

BACKGROUND

Anorexia nervosa (AN) is a chronic and disabling psychiatric condition characterized by low hedonic drive towards food, and is thought to be inclusive of altered dimensions of reward processing. Whether there exists a fundamental aberrancy in the capacity to acquire and maintain de novo hedonic associations-a critical component of hedonic responding-has never been studied in AN.

METHODS

This multi-modal study will employ a 2-day Pavlovian appetitive conditioning paradigm to interrogate the (1) acquisition, (2) extinction, (3) spontaneous recovery and (4) reinstatement of appetitive learning in adolescents and young adults with AN. Participants will be 30 currently ill, underweight individuals with AN; 30 weight-restored individuals with AN; and 30 age-matched healthy controls, all aged 12-22 years. All subjects will undergo clinical assessment, followed by the 2-day appetitive conditioning task during which fMRI, pupillometry, heart rate deceleration, and subjective ratings will be acquired.

DISCUSSION

This study will be the first to interrogate appetitive conditioning in AN-a disorder characterized by altered hedonic responding to food. Results will help establish objective biomarkers of appetitive conditioning in AN and lay the groundwork for developing novel lines of treatment for AN and other psychiatric disorders involving diminished ability to experience pleasure and reward.

TRIAL REGISTRATION

Pending.

INTENDED REGISTRY

Clinicaltrials.gov.

Sensor technology in eating disorders research: A systematic review

OBJECTIVE

Sensor technologies offer exciting potential to objectively measure psychopathological correlates of eating pathology and eating disorder (ED) research utilizing sensors has rapidly proliferated in the past several years. The aims of the present review are: (1) characterize the types of sensors that have been utilized in ED research, (2) identify the psychopathological factors relevant to EDs that have been assessed using sensors, (3) describe the data supporting the validity and reliability of these sensors, (4) discuss limitations associated with these sensors, and (5) identify gaps that persist within the ED literature with regard to use of sensor technologies.

METHOD

A systematic search was conducted of PubMed, PsycINFO, Web of Science, ProQuest, and "gray" literature sources. Eligible publications were empirical studies that utilized sensors to measure at least one psychological variable among clinical ED populations.

RESULTS

Sensors have been utilized with ED samples to measure eating behaviors, physical activity, sleep, autonomic nervous system activity, eyeblink startle response, visual attention, and visual-haptic object integration. The reliability and validity of these sensors varies widely and there are a number of significant gaps that remain in the literature with regard to the types of sensors utilized, context in which sensors have been used, and populations studied.

DISCUSSION

The existing literature utilizing sensors within ED research largely support the feasibility and acceptability of these tools. Sensors should continue to be utilized within the field, with a specific focus on examining the reliability and validity of these tools within ED samples and increasing the diversity of samples studied.

PUBLIC SIGNIFICANCE STATEMENT

Sensor technologies, such as those included in modern smartwatches, offer new opportunities to measure factors that may maintain or contribute to symptoms of eating disorders. This article describes the types of sensors that have been used in eating disorders research, challenges that may arise in using these sensors, and discusses new applications of these sensors that may be pursued in future research.

Disgust and Self-Disgust in Eating Disorders: A Systematic Review and Meta-Analysis

Disgust and self-disgust are aversive emotions which are often encountered in people with eating disorders. We conducted a systematic review and meta-analysis of disgust and self-disgust in people with eating disorders using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The systematic review of the literature revealed 52 original research papers. There was substantial heterogeneity regarding the research question and outcomes. However, we found 5 articles on disgust elicited by food images, 10 studies on generic disgust sensitivity, and 4 studies on self-disgust, and we proceeded to a meta-analytic approach on these studies. We found that women with eating disorders have significantly higher momentary disgust feelings in response to food images (1.32; 95% CI 1.05, 1.59), higher generic disgust sensitivity (0.49; 95% CI 0.24, 0.71), and higher self-disgust (1.90; 95% CI 1.51, 2.29) compared with healthy controls. These findings indicate the potential clinical relevance of disgust and self-disgust in the treatment of eating disorders.

An implicit priming intervention alters brain and behavioral responses to high-calorie foods: a randomized controlled study

BACKGROUND

Conditioned food cues (e.g., smell, sight) can affect intake of foods associated with those cues, regardless of homeostatic need. As such, altering automatic associations with food cues could support weight loss or maintenance efforts by affecting the salience of those cues and the effort required to resist consumption.

OBJECTIVES

This study investigated neuronal and behavioral effects of an implicit priming (IP) intervention, in which negatively valenced images were paired with high-calorie foods and positively valenced images with low-calorie foods. Priming images were presented immediately before food images, but below conscious perception (20 ms). We hypothesized that this evaluative conditioning approach could alter food cue responses by modifying affective associations.

METHODS

The final sample included 41 adults with BMI ≥25 kg/m2 (n = 22, active IP; n = 19, control IP). In control IP, food images were primed with neutral, scrambled images. Participants completed a visual food cue task during fMRI, both before and after IP. To determine the replicability of prior behavioral findings, food image ratings were completed before and after IP as a secondary outcome.

RESULTS

In a whole-brain analysis, reduced dorsolateral prefrontal cortex (dlPFC) response to high-calorie foods was observed after active compared with control IP (t = 4.93, P = 0.033). With a region of interest analysis, reduced response to high-calorie foods in active compared with control IP was also observed in the striatum (t = 2.40, P = 0.009) and insula (t = 2.38, P = 0.010). Active compared with control IP was associated with reduced high-calorie food ratings (F = 4.70, P = 0.038).

CONCLUSIONS

Reduced insula and striatum response to high-calorie foods after active compared with control IP suggests effectiveness of IP in altering food cue salience. Reduced dlPFC response to high-calorie foods after active compared with control IP may reflect fewer attentional resources being directed to those images and reduced engagement of inhibitory processes.This trial was registered at clinicaltrials.gov as NCT02347527.

The Role of Negative Affect in Emotional Processing of Food-Related Images in Eating Disorders and Obesity

The aim of the present study was to analyze differences in the emotional processing (valence, arousal, and dominance) of food-related information in patients with eating disorders (ED), patients with obesity, and healthy women. Moreover, the mediator role of negative affect and the moderating role of the diagnostic group (ED vs. non-ED) were analyzed.

METHOD

The sample consisted of 94 women (39 with eating disorders, 19 with obesity, and 36 healthy participants).

MEASURES

International Affective Picture System (IAPS) food picture exposure task; Self-Assessment Manikin Analog-Visual Scale (SAM) appraising Arousal, Valence, and Dominance; Eating Attitudes Test (EAT-26); Positive and Negative Affect Schedule (PANAS).

RESULTS

Patients with purging symptomatology rated food images as more unpleasant than healthy women. Patients with purging and restrictive eating symptomatology showed higher levels of arousal and less dominance over the emotions experienced, compared to patients with obesity and healthy women. The mediation analysis showed that negative affect mediated the relationship between eating symptomatology (EAT-26) and the Valence of food images, as well as the control over the emotions experienced when viewing food images (Dominance). For the moderation analysis participants were regrouped into two groups (ED patients vs. non-ED patients). The direct relationship between eating symptomatology and food image valence was moderated by the diagnostic group. However, the group did not moderate the direct relationship between the EAT-26 and dominance over experienced emotions, or the indirect effect on eating symptomatology through negative affect. These results show the relevance of negative affect in the emotional processing of food-related information, and they support an eating disorder-disordered eating dimensional perspective.

Implicit bias to food and body cues in eating disorders: a systematic review

BACKGROUND

Rigid, restrictive eating patterns, fear of gaining weight, body image concerns, but also binge eating episodes with loss of control leading to overweight, at times followed by compensatory measures to control weight, are typical symptoms in eating disorders (EDs). The regulation of food intake in EDs may underlie explicit processes that require cognitive insight and conscious control or be steered by implicit mechanisms that are mostly automatic, rapid, and associated with affective-rather than cognitive-processing. While introspection is not capable of assessing implicit responses, so-called indirect experimental tasks can assess implicit responses underlying a specific behavior by-passing the participant's consciousness. Here, we aimed to present the current evidence regarding studies on implicit biases to food and body cues in patients with EDs.

METHODS

We performed a systematic review (PRISMA guidelines). We included controlled studies performed in clinical ED cohorts (vs. healthy control subjects or another control condition, e.g., restrictive vs. binge/purge AN) and using at least one indirect assessment method of interest.

RESULTS

Out of 115 screened publications, we identified 29 studies fulfilling the eligibility criteria, and present a synthesis of the essential findings and future directions.

CONCLUSION

In this emerging field of research, the present work provides cornerstones of evidence highlighting aspects of implicit regulation in eating disorders. Applying both direct (e.g., self-reports) and indirect measures for the assessment of both explicit and implicit responses is necessary for a comprehensive investigation of the interplay between these different regulatory mechanisms and eating behavior. Targeted training of implicit reactions is already in use and represents a useful future tool as an add-on to standard psychotherapeutic treatments in the battle against eating disorders.

EVIDENCE LEVEL

1 (systematic review).

Physiological, emotional and neural responses to visual stimuli in eating disorders: a review

BACKGROUND

Overconcern with food and shape/weight stimuli are central to eating disorder maintenance with attentional biases seen towards these images not present in healthy controls. These stimuli trigger changes in the physiological, emotional, and neural responses in people with eating disorders, and are regularly used in research and clinical practice. However, selection of stimuli for these treatments is frequently based on self-reported emotional ratings alone, and whether self-reports reflect objective responses is unknown.

MAIN BODY

This review assessed the associations across emotional self-report, physiological, and neural responses to both food and body-shape/weight stimuli in people with anorexia nervosa (AN), bulimia nervosa (BN) and binge eating disorder (BED). For food stimuli, either an aversive or lack of physiological effect was generated in people with AN, together with a negative emotional response on neuroimaging, and high subjective anxiety ratings. People with BN showed a positive self-rating, an aversive physiological reaction, and a motivational neural response. In BED, an aversive physiological reaction was found in contrast to motivational/appetitive neural responses, with food images rated as pleasant. The results for shape/weight stimuli showed aversive responses in some physiological modalities, which was reflected in both the emotional and neural responses, but this aversive response was not consistent across physiological studies.

CONCLUSIONS

Shape/weight stimuli are more reliable for use in therapy or research than food stimuli as the impact of these images is more consistent across subjective and objective responses. Care should be taken when using food stimuli due to the disconnect reported in this review.

Electromyographic evidence of reduced emotion mimicry in individuals with a history of non-suicidal self-injury

Engaging in facial emotion mimicry during social interactions encourages empathy and functions as a catalyst for interpersonal bonding. Decreased reflexive mirroring of facial expressions has been observed in individuals with different non-psychotic disorders, relative to healthy controls. Given reports of interpersonal relationship difficulties experienced by those who engage in non-suicidal self-injury (NSSI), it is of interest to explore facial emotion mimicry in individuals with a history of this behaviour (HNSSI). Among other things, this will enable us to better understand their emotion regulation and social interaction challenges. Surface facial electromyography (fEMG) was used to record the reflexive facial mimicry of 30 HNSSI and 30 controls while they passively observed a series of dynamic facial stimuli showing various facial expressions of emotion. Beginning with a neutral expression, the stimuli quickly morphed to one of 6 prototypic emotional expressions (anger, fear, surprise, disgust, happiness, or sadness). Mimicry was assessed by affixing surface electrodes to facial muscles known to exhibit a high degree of electrical activity in response to positive and negative emotions: the corrugator supercilii and the zygomaticus major. HNSSI participants, relative to controls, exhibited significantly less electrical activity in the corrugator muscle in response to viewing angry stimuli, and significantly less of an expected relaxation in muscle activity in response to viewing happy stimuli. Mirroring these results, greater endorsement of social influence as a motivator for engaging in NSSI was associated with less mimicry, and greater endorsement of emotion regulation as a motivator was associated with greater incongruent muscle response when viewing happy faces. These findings lend support to the theory that social interaction difficulties in HNSSI might be related to implicit violations of expected social rules exhibited through facial mimicry nonconformity.

Implicit and explicit motivational responses to high- and low-calorie food in women with disordered eating

Eating disorders and their symptoms are thought to be associated with altered motivational responding to food. Binge eating may relate to increased reward reactivity, restrictive eating may be associated with increased threat and/or decreased reward reactivity, and the combination of these symptoms within an individual may be linked to motivational conflict to food. Using both implicit (i.e., physiological) and explicit (i.e., self-reported) measures, we tested these hypotheses in 88 women with binge eating only, restrictive eating only, both binge eating and restrictive eating, or no eating pathology. Participants viewed and rated high-calorie food, low-calorie food, and emotional images while startle eye blink and postauricular reflexes were measured. Arousal and craving, but not valence, ratings were significantly greater for high- than low-calorie food. Startle blink reflexes during all food images were significantly lower than during neutral images, whereas only high-calorie foods related to greater postauricular reactivity than neutral images. Eating pathology group did not predict implicit and explicit motivational reactions to food. Exploratory dimensional analyses revealed that rating low-calorie foods as lower on craving predicted endorsement of restrictive eating, while rating low-calorie foods as lower on valence and arousal, and experiencing lower postauricular reactivity to high-calorie foods minus neutral images, predicted greater frequency of restrictive eating episodes. Decreased implicit and explicit appetitive motivation to high- and low-calorie food may relate to the presence and frequency of restrictive eating. Future longitudinal research should investigate whether decreased appetitive responding to food is a risk factor for, versus consequence of, restrictive eating.

Attention towards food: Conflicting mechanisms in anorexia nervosa

In Anorexia nervosa (AN) attentional biases towards, as well as away from, food cues have been found using different paradigms. In the current study, adult and adolescent AN patients and control participants performed two tasks while their eye movements were recorded. The tasks involved viewing and rating: 1. Single photographs of food items; 2. Pairs of pictures consisting of one picture of high calorie and one of low calorie food. Girls and women suffering from AN rated pictures of high calorie food as more negative than control participants. In the task showing single food pictures, reduced fixation times within Regions of Interest of low calorie food were seen in AN; during the task using picture pairs, a visual attentional bias towards low calorie and away from high calorie stimuli for AN was demonstrated. There is evidence for heightened visual attentional capture by high calorie stimuli when presented alone as well as attraction of attention by low calorie stimuli when shown next to high calorie stimuli, possibly facilitated by avoidance of the latter. Different attentional mechanisms seem to be activated when only one stimulus is shown compared to when two stimuli are competing for the viewer's attention.

Moving towards specificity: A systematic review of cue features associated with reward and punishment in anorexia nervosa

Models of anorexia nervosa (AN) posit that symptoms are maintained through deficient reward and enhanced punishment processing. However, theoretical and empirical inconsistencies highlight the need for a more nuanced conceptualization of this literature. Our goal was to comprehensively review the research on reward and punishment responding in AN from a cue-specific lens to determine which stimuli evoke or discourage reward and punishment responses in this population, and, ultimately, what properties these rewarding and punishing cues might share. A systematic review interrogating reward and punishment responses to specific cues yielded articles (n = 92) that examined responses to disorder relevant (e.g., food) and irrelevant (e.g., money) stimuli across self-report, behavioral, and biological indices. Overall, in most studies individuals with AN exhibited aversive responses to cues signaling higher body weights, social contexts, and monetary losses, and appetitive responses to cues for weight loss behaviors and thinness. Findings were more mixed on responses to palatable food and monetary gains. Results highlight that reward and punishment responding in AN are context specific and may be affected by varied stimulus qualities (e.g., predictability, controllability, delay, effort). Increasing specificity in future research on reward and punishment mechanisms in AN will better inform development of precisely-targeted interventions.

Do emotional responses to food images differ within different types of eating disorders?

OBJECTIVES

To investigate emotional responses to food images in women with eating disorders (EDs) and healthy controls (HCs); and in underweight individuals post weight-restoration.

METHODS

Women (>14 years) with (n = 139) and without (n = 41) an ED rated food images evoking fear, disgust and happiness on a three-visual-analogue scale. Underweight participants viewed the images at two time-points; pre- and post-weight-restoration.

RESULTS

HCs were significantly happier, less fearful/anxious prior to viewing the images compared with EDs. Negative emotional responses when viewing images were significantly greater (p < .001) in EDs compared with HCs; however, groups did not differ in happiness. Emotional responses were not significantly different within the ED groups. At post weight-restoration, individuals were significantly less anxious/disgusted when viewing the images.

CONCLUSIONS

The importance of considering emotional responses when discussing food consumption in EDs trans-diagnostically is highlighted. Weight recovery reduces negative food responses, although responses remained high in comparison to HCs.

Dysfunction of the to in Anorexia and Bulimia Nervosa: A fMRI

Brain reward dysfunction in eating disorders has been widely reported. However, whether the neural correlates of hedonic and motivational experiences related to food cues are differentially affected in anorexia nervosa of restrictive type (ANr), bulimia nervosa (BN), and healthy control (HC) participants remains unknown. Here, 39 women (14 ANr, 13 BN, and 12 HC) underwent fMRI while smelling food or non-food odors in hunger and satiety states during liking and wanting tasks. ANr and BN patients reported less desire to eat odor-cued food and odor-cued high energy-density food (EDF), respectively. ANr patients exhibited lower ventral tegmental area (VTA) activation than BN patients to food odors when rating their desire to eat, suggesting altered incentive salience attribution to food odors. Compared with HC participants, BN patients exhibited decreased activation of the caudate nucleus to food odors in the hunger state during the wanting task. Both patient groups also showed reduced activation of the anterior ventral pallidum and insula in response to high EDF odors in the hunger state during the wanting task. These findings indicate that brain activation within the food reward-regulating circuit differentiates the three groups. ANr patients further exhibited lower activation of the precuneus than other participants, suggesting a possible role of body image distortion in ANr. Our study highlights that food odors are relevant sensory probes to gain better insight into the dysfunction of the mesolimbic and striatal circuitry involved in food reward processing in patients with EDs.

Blunted emotion-modulated startle reflex in anorexia nervosa

OBJECTIVE

Patients with anorexia nervosa (AN) often show difficulties in the perception, expression, and regulation of emotions and a strong avoidance of aversive feelings. According to psychobiological models, dietary restraint and accompanying weight loss may serve as a maladaptive mechanism of emotion regulation by attenuating aversive emotional states in AN, thereby contributing to the maintenance of the disorder.

METHOD

Twenty-seven women with AN and 26 age-matched healthy women were shown short film-clips to elicit fear, sadness, amusement, and neutral emotional states. Eyeblink startle response was measured by electromyography in reaction to startle-eliciting acoustic stimuli presented 12 times binaurally during each film-clip.

RESULTS

As compared to healthy controls, patients with AN showed a blunted startle response to the fear- but not to the sadness-eliciting stimulus.

DISCUSSION

The findings support the assumption that underweight is associated with attenuated emotional reactivity to fear-eliciting material in AN. This is in line with the hypothesis that starvation and low body weight constitute a maladaptive mechanism of emotion regulation in AN, contributing to the maintenance of the disorder.

What can food-image tasks teach us about anorexia nervosa? A systematic review

A salient feature of anorexia nervosa (AN) is the persistent and severe restriction of food, such that dietary intake is inadequate to maintain a healthy body weight. Experimental tasks and paradigms have used illness-relevant stimuli, namely food images, to study the eating-specific neurocognitive mechanisms that promote food avoidance. This systematic review, completed in accordance with PRISMA guidelines, identified and critically evaluated paradigms involving images of food that have been used to study AN. There were 50 eligible studies, published before March 10th 2018, identified from Medline and PsychINFO searches, and reference screening. Studies using food image-based paradigms were categorised into three methodologic approaches: neuropsychology, neurophysiology, and functional magnetic resonance imaging (fMRI). Paradigms were reviewed with a focus on how well they address phenomena central to AN. Across tasks, differences between individuals with AN and healthy peers have been identified, with the most consistent findings in the area of reward processing. Measuring task performance alongside actual eating behaviour, and using experimental manipulations to probe causality, may advance understanding of the mechanisms of illness in AN.

Anorexia nervosa, neuroimaging research, and the contextual salience of food cues: The food approach-avoidance conundrum

Anorexia nervosa (AN) is characterized by an avoidance and marked apprehension around food intake, yet paradoxically, those with AN often display approach behaviors to food, engaging in food shopping or preparation activities which are described as rewarding. This approach-avoidance conundrum is of much importance as neuroimaging studies continue to probe mechanisms relating to core AN psychopathology. This Idea Worth Researching discusses the notion that neuroimaging studies relying on food cue presentation paradigms may be methodologically flawed without specifying the contextual salience of the food cues presented in paradigms. The appraisal of food cues may diverge as a function of one's intent-to-eat, and thus, neuroimaging studies not specifying the contextual salience of food cues (i.e., intent-to-eat or not) may confound two distinctly different processes.

Attentional and physiological processing of food images in functional dyspepsia patients: A pilot study

The food-related behavior of functional dyspepsia has been attracting more interest of late. This pilot study aims to provide evidence of the physiological, emotional, and attentional aspects of food processing in functional dyspepsia patients. The study was performed in 15 functional dyspepsia patients and 17 healthy controls after a standard breakfast. We measured autonomic nervous system activity using skin conductance response and heart rate variability, emotional response using facial electromyography, and visual attention using eyetracking during the visual stimuli of food/non-food images. In comparison to healthy controls, functional dyspepsia patients showed a greater craving for food, a decreased intake of food, more dyspeptic symptoms, lower pleasantness rating of food images (particularly of high fat), decreased low frequency/high frequency ratio of heart rate variability, and suppressed total processing time of food images. There were no significant differences of skin conductance response and facial electromyography data between groups. The results suggest that high level cognitive functions rather than autonomic and emotional mechanisms are more liable to function differently in functional dyspepsia patients. Abnormal dietary behavior, reduced subjective rating of pleasantness and visual attention to food should be considered as important pathophysiological characteristics in functional dyspepsia.

Facial expression to emotional stimuli in non-psychotic disorders: A systematic review and meta-analysis

Facial expression of emotion is crucial to social interaction and emotion regulation; therefore, altered facial expressivity can be a contributing factor in social isolation, difficulties with emotion regulation and a target for therapy. This article provides a systematic review and meta-analysis of the literature on automatic emotional facial expression in people with non-psychotic disorders compared to healthy comparison groups. Studies in the review used an emotionally salient visual induction method, and reported on automatic facial expression in response to congruent stimuli. A total of 39 studies show alterations in emotional facial expression across all included disorders, except anxiety disorders. In depression, decreases in facial expression are mainly evident for positive affect. In eating disorders, a meta-analysis showed decreased facial expressivity in response to positive and negative stimuli. Studies in autism partially support generally decreased facial expressivity in this group. The data included in this review point towards decreased facial emotional expressivity in individuals with different non-psychotic disorders. This is the first review to synthesise facial expression studies across clinical disorders.

Emotional processing of infants displays in eating disorders

AIM

The aim of this study is to examine emotional processing of infant displays in people with Eating Disorders (EDs).

BACKGROUND

Social and emotional factors are implicated as causal and maintaining factors in EDs. Difficulties in emotional regulation have been mainly studied in relation to adult interactions, with less interest given to interactions with infants.

METHOD

A sample of 138 women were recruited, of which 49 suffered from Anorexia Nervosa (AN), 16 from Bulimia Nervosa (BN), and 73 were healthy controls (HCs). Attentional responses to happy and sad infant faces were tested with the visual probe detection task. Emotional identification of, and reactivity to, infant displays were measured using self-report measures. Facial expressions to video clips depicting sad, happy and frustrated infants were also recorded.

RESULTS

No significant differences between groups were observed in the attentional response to infant photographs. However, there was a trend for patients to disengage from happy faces. People with EDs also reported lower positive ratings of happy infant displays and greater subjective negative reactions to sad infants. Finally, patients showed a significantly lower production of facial expressions, especially in response to the happy infant video clip. Insecure attachment was negatively correlated with positive facial expressions displayed in response to the happy infant and positively correlated with the intensity of negative emotions experienced in response to the sad infant video clip.

CONCLUSION

People with EDs do not have marked abnormalities in their attentional processing of infant emotional faces. However, they do have a reduction in facial affect particularly in response to happy infants. Also, they report greater negative reactions to sadness, and rate positive emotions less intensively than HCs. This pattern of emotional responsivity suggests abnormalities in social reward sensitivity and might indicate new treatment targets.

Motivational processing of food cues in anorexia nervosa: a pilot study

Current literature suggests an increased attentional bias toward food stimuli in eating-disordered individuals compared to healthy controls. In line with these research efforts, the present study aims to investigate the processing of food stimuli (enriched by emotional stimuli) between patients diagnosed for anorexia nervosa (AN) and healthy controls by means of electroencephalography. Twenty-two female adolescents (eleven AN patients vs. eleven healthy controls) were investigated. Positive event-related potentials "P300" and "late positive potential" (LPP) reflecting attentional processing (caused by motivationally relevant stimuli) were investigated during passive viewing of the food cue picture stream. This method was used for the first time in a sample of individuals with AN. As a main result, AN patients exhibited a higher amount of attentional bias in P300 and LPP, while watching food stimuli. Moreover, AN patients rated food stimuli as less pleasant. For a conclusion, there is substantial evidence pointing to an abnormal attentional brain reactivity to food pictures in AN. Therefore, food stimuli seem to be more motivationally relevant for AN patients than for healthy controls. By broadening existing knowledge, these findings might bear some implications for the treatment for AN. However, further research is recommended in order to confirm the results coming from rather limited data.

Social reward and rejection sensitivity in eating disorders: an investigation of attentional bias and early experiences

OBJECTIVES

People with eating disorders (EDs) have difficulties with social functioning. One explanatory mechanism is a problem with over-sensitivity to rejection and/or low sensitivity to social reward. The aim of this study is to investigate attentional bias to facial stimuli in people with a lifetime diagnosis of EDs and healthy controls (HCs) and to test whether these attentional biases are linked to adverse early experiences.

METHODS

Forty-six participants with a current diagnosis of EDs (29 with anorexia nervosa (AN) and 17 with bulimia nervosa (BN)), 22 participants recovered from an eating disorder (13 with past AN and nine with past BN) and 50 HCs completed a dot-probe task with faces expressing rejection and acceptance. Participants reported on parental style and adverse early experiences.

RESULTS

People with a lifetime diagnosis of EDs show an attentional bias to rejecting faces and a difficulty disengaging attention from these stimuli. Also, they had a sustained attentional avoidance of accepting faces. HCs demonstrated the opposite attentional pattern. The attentional bias to rejection was correlated with adverse childhood experiences.

CONCLUSIONS

People with an EDs show vigilance to rejection and avoidance of social reward. This may contribute to the causation or maintenance of the illness.

Emotional facial expression in women recovered from anorexia nervosa

BACKGROUND

Recent models of anorexia nervosa (AN) have emphasised the importance of social and emotional difficulties as maintenance factors of the disorder, however, empirical data are limited. The aim of this study was to examine whether altered emotional facial expression, previously observed in people currently ill with anorexia nervosa, is limited to the ill state or present in people recovered from the illness.

METHODS

The sample consisted of 123 participants [49 AN, 21 recovered AN (RecAN) and 53 healthy controls (HC)]. Participants watched three films clips (amusing, neutral, sad) whilst their facial expressions were recorded and completed the positive and negative affect scale (PANAS) to record subjective experience. Facial expressions were subsequently coded for frequency of positive and negative expression and frequency of looking away.

RESULTS

In response to the amusing clip, AN participants showed significantly less positive expression than both HC and RecAN groups and both AN and RecAN showed more negative expression than HC with no difference between groups in looking away.In response to the sad clip there was no difference between groups in positive expression, but current AN participants showed significantly less negative expression than HC and looked away from the stimuli more than RecAN or HC.In terms of their subjective emotional experience, patients with current AN reported less positive emotion in response to both the amusing and the sad film clip. There was no difference between groups in subjective negative experience.

CONCLUSIONS

Alterations in facial expression are present in people currently ill with AN contributing to the social difficulties found in AN and potentially exacerbating resistance to treatment. Some alterations in facial expression are found in women with a past history of AN but not to the same extent as those shown in the currently ill group. Future studies need to use a wider range of stimuli involving different emotions to corroborate findings.

Personality subtypes in adolescents with anorexia nervosa

The aims of this study are to (1) empirically identify the personality subtypes of adolescents with anorexic disorders and (2) investigate the personality disorders, identity disturbances, and affective features associated with the different subtypes. We assessed 102 adolescent patients with Eating Disorders (anorexia nervosa and eating disorder not otherwise specified) using three clinical instruments: the Shedler-Westen Assessment Procedure for Adolescents (SWAP-200-A) (Westen D, Shedler J, Durrett C, Glass S, Martens A. Personality diagnoses in adolescence: DSM-IV Axis II diagnoses and an empirically derived alternative. Am J Psychiatry 2003;160:952-966), the Affective Regulation and Experience Questionnaire (AREQ) (Zittel Conklin C, Bradley R, Westen D. Affect regulation in borderline personality disorder. J Nerv Ment Dis 2006;194:69-77), and the Identity Disorder Questionnaire (IDQ) (Wilkinson-Ryan T, Westen D. Identity disturbance in borderline personality disorder: An empirical investigation. Am J Psychiatry 2000;157:528-541). We performed a Q factor analysis of the SWAP-200-A descriptions of our sample to identify personality subtypes. We correlated these personality styles with AREQ and IDQ factors and explored the personality differences among individuals with the different types of ED. The Q factor analysis identified three personality subtypes: high-functioning/perfectionist, emotionally dysregulated, and overcontrolled/constricted. Each subtype showed specific identity and affective features, comorbidities with different personality disorders, and clinical implications. These results contribute to the understanding of adolescents with ED and seem to be relevant for treatment planning.

Children's reward responses to picture- and odor-cued food stimuli: a developmental analysis between 6 and 11years

The reward system is largely involved in the control of food intake. Whether components of this system (i.e., wanting and liking) change during development remains understudied, as well as how proximate factors (sensory cues, motivational state) modulate reward reactivity across development. We examined the developmental pattern of wanting and liking for sensorily-cued food stimuli in 6-11year old children as a function of the child's motivational state (hunger/satiety), gender, and the nature of foods. School children were exposed before or after their lunch on alternative days to visual and odor stimuli representing different categories of familiar foods. Their task was to rate wanting and liking of pictures and odorants of pizza, meat, vegetables, fruits, and chocolate. The following results were found: (1) While liking appeared to be stable from age 6 to 11, more particularly for visually-cued foods, wanting decreased, as well as did subjective hunger perception; (2) there were smaller or absent state-effects in 7-to-9-year-olds; (3) reward ratings were higher in boys than in girls; (4) reward ratings of vegetables were the lowest at all ages. These results suggest that wanting, but not liking, is developmentally variable over childhood, and that this variation depends on age, gender, motivational state (hunger/satiety), the nature of the food and the modality of the sensory cue representing it. Such developmental changes are discussed in relation to biological (adiposity rebound) and cognitive (dietary restraint) factors influencing the motivation to eat during middle (6-7years) and late (9-11years) childhood.

Low baseline startle in anorexia nervosa patients

This study examined baseline startle magnitude, using eye blink response and skin conductance response in anorexia nervosa patients. Twenty female in-patients with anorexia nervosa and an equal number of female healthy controls were tested. Baseline startle response was assessed during blank screens while four startling loud sounds (a 116 dB, 1s, 250 Hz tone) were delivered with a time interval ranging from 35 to 55 s. It was investigated if BMI and state anxiety correlated with physiological responses. The clinical sample showed a lower baseline startle reflex measured with both indices, than healthy controls. Across the whole sample, a single regression model partially explained the relationship between BMI and baseline skin conductance response.

The facial and subjective emotional reaction in response to a video game designed to train emotional regulation (Playmancer)

Several aspects of social and emotional functioning are abnormal in people with eating disorders. The aim of the present study was to measure facial emotional expression in patients with eating disorders and healthy controls whilst playing a therapeutic video game (Playmancer) designed to train individuals in emotional regulation. Participants were 23 ED patients (11 AN, 12 BN) and 11 HCs. ED patients self reported more anger at baseline but expressed less facial expression of anger during the Playmancer game. The discrepancy between self-report and non-verbal expression may lead to problems in social communication.

Subliminal food images compromise superior working memory performance in women with restricting anorexia nervosa

Prefrontal cortex (PFC) is dysregulated in women with restricting anorexia nervosa (RAN). It is not known whether appetitive non-conscious stimuli bias cognitive responses in those with RAN. Thirteen women with RAN and 20 healthy controls (HC) completed a dorsolateral PFC (DLPFC) working memory task and an anterior cingulate cortex (ACC) conflict task, while masked subliminal food, aversive and neutral images were presented. During the DLPFC task, accuracy was higher in the RAN compared to the HC group, but superior performance was compromised when subliminal food stimuli were presented: errors positively correlated with self-reported trait anxiety in the RAN group. These effects were not observed in the ACC task. Appetitive activation is intact and anxiogenic in women with RAN, and non-consciously interacts with working memory processes associated with the DLPFC. This interaction mechanism may underlie cognitive inhibition of appetitive processes that are anxiety inducing, in people with AN.

Bone mineral density in young women on methadone substitution

Little is known about bone mineral density (BMD) in patients with heroin addiction and subsequent methadone substitution. The goal of this study was to compare bone mass density of young HIV-negative women on long-term methadone treatment to a local group of young healthy women. Eleven women (aged 20-29) with previous heroin dependence and current methadone substitution (20-140 mg, median 60, daily) for 1.5-9 (median 3) years were compared to 30 healthy women (aged 20-28). Participants were examined with dual-energy X-ray absorptiometry of the lumbar spine (L2-L4), of the total proximal hip area, and of the femoral neck. Patients and controls had neither current nor lifetime underweight condition, had comparable ages at menarche, and did not differ significantly in current body mass index (21.9 ± 4.0, respectively, 20.5 ± 1.5 kg/m(2)) in spite of a largely unhealthy lifestyle (cigarette, alcohol, and cocaine consumption in patients). Patients' total-hip parameters were marginally lower than those of controls (BMD P = 0.054, T score P = 0.049), whereas the femoral neck and lumbar spine parameters did not differ significantly between the two groups. Long-term methadone substitution in HIV-negative women seems to slightly affect bone mass density.

Evoked facial emotional expression and emotional experience in people with anorexia nervosa

OBJECTIVE

To use an experimental paradigm to assess facial expression, subjective experience of emotion and the relationship between them in people with anorexia nervosa (AN).

METHOD

Film clips are used to elicit emotion and participants' facial expression and subjective experience are recorded. Thirty inpatients with AN and 34 healthy control (HC) women are included in the study.

RESULTS

People with AN are less facially expressive than HC while watching positive and negative film clips and report feeling less positive emotion than HC but not less negative emotion. People with AN look away significantly more than HC during the negative film clip. Duration of illness and depression relate to attenuated positive facial expression and eating pathology to attenuated negative facial expression.

DISCUSSION

This experimental study supports self report studies showing people with AN attenuate emotional expression and avoid negative affect. Such behavior may affect social interaction and contribute to the maintenance of the disorder.

Attentional processing of food pictures in individuals with anorexia nervosa--an eye-tracking study

BACKGROUND

Etiologic models of anorexia nervosa (AN) suggest that cognitive factors play a crucial role in the disorder's psychopathology. Attentional aspects of food processing in AN remain largely unknown. Both an early attentional bias (vigilance) and inattentiveness (avoidance) to food pictures have been reported in patients with eating disorders. The study's aim was to examine the vigilance-avoidance hypothesis concerning food information processing by unraveling the time course of attention deployment in individuals with AN.

METHODS

We used eye-tracking to examine continuous attention deployment in 19 individuals with AN during free visual exploration of food pictures versus nonfood pictures compared with 18 fasted and 20 nonfasted healthy control subjects.

RESULTS

Compared with healthy control subjects, AN patients allocated overall less attention to food pictures but showed no early attentional bias toward food pictures. Attentional engagement for food pictures was most pronounced in fasted healthy control subjects. The extent of attention deployment in AN patients was associated with indicators of the disorder's severity.

CONCLUSIONS

Gaze data suggest that individuals with AN show no early vigilance but later avoidance when confronted with food information. This suggests that initially, AN patients perceive incentive salience from food information because they process food pictures in the same way healthy control subjects do. The time course of attention deployment suggests that it is only after a first phase of stimulus encoding and labeling as food that individuals with AN avoid food pictures. This pattern of attention deployment is probably mediated by disorder-specific dysfunctional cognitions.

Eating in eating disorders

The aim of this paper is to bring eating back into the centre of the eating disorder discourse. The ability to interrogate and understand the central processes of appetite has increased considerably since the discovery of leptin and the ability to observe brain function with scanning methodologies. This has led to substantial progress in understanding the biological causative and maintaining factors in eating disorders, opening up the possibility of translating the latest findings into new forms of treatment. The biological mechanisms underpinning symptoms evolution and course of illness will first be described, follows by a discussion on integrating the research evidence in fear and feeding into patient care.

Hedonic reactivity to visual and olfactory cues: rapid facial electromyographic reactions are altered in anorexia nervosa

Though it has been suggested that hedonic processing is altered in anorexia nervosa (AN), few studies have used objective measures to assess affective processes in this eating disorder. Accordingly, we investigated facial electromyographic, autonomic and subjective reactivity to the smell and sight of food and non-food stimuli, and assessed more particularly rapid facial reactions reflecting automatic processing of pleasantness. AN and healthy control (HC) women were exposed, before and after a standardized lunch, to pictures and odorants of foods differing in energy density, as well as to non-food sensory cues. Whereas the temporal profile of zygomatic activity in AN patients was typified by a fast drop to sensory cues within the 1000 ms following stimulus onset, HC showed a larger EMG reactivity to pictures in a 800-1000 ms time window. In contrast, pleasantness ratings discriminated the two groups only for high energy density food cues suggesting a partial dissociation between objective and subjective measures of hedonic processes in AN patients. The findings suggest that the automatic processing of pleasantness might be altered in AN, with the sensitivity to reward being modulated by controlled processes.

Pleasure for visual and olfactory stimuli evoking energy-dense foods is decreased in anorexia nervosa

Although patients with anorexia nervosa have been suggested to be anhedonic, few experiments have directly measured their sensory pleasure for a range of food and non-food stimuli. This study aimed to examine whether restrictive anorexia nervosa (AN-R) patients displayed: i) a generalized decline in sensory pleasure or only in food-related sensory pleasure; ii) a modification of hedonic responses to food cues (liking) and of the desire to eat foods (wanting) as a function of their motivational state (hunger vs. satiety) and energy density of foods (high vs. low). Forty-six female participants (AN-R n=17; healthy controls (HC) n=29) reported before/after lunch their pleasure for pictures/odorants representing foods of different energy density and non-food objects. They also reported their desire to eat the foods evoked by the sensory stimuli, and completed the Physical Anhedonia Scale and the Beck Depression Inventory. AN-R and HC participants did not differ on liking ratings when exposed to low energy-density food or to non-food stimuli. The two groups also had similar physical anhedonia scores. However, compared to HC, AN-R reported lower liking ratings for high energy food pictures regardless of their motivational state. Olfactory pleasure was reduced only during the pre-prandial state in the AN-R group. The wanting ratings showed a distinct pattern since AN-R participants reported less desire to eat the foods representing both low and high energy densities, but the effect was restricted to the pre-prandial state. Taken together these results reflect more the influence of core symptoms in anorexia nervosa (fear of gaining weight) than an overall inability to experience pleasure.