A naturalistic examination of negative affect and disorder-related rumination in anorexia nervosa

Tension and disordered eating behaviors in the daily lives of adolescents and young adults from the general population: Associations and moderating role of trait emotion regulation

Experiences of tension and difficulties in emotion regulation have been linked to eating pathology in clinical samples and are targeted in respective treatment approaches. The present study aimed to investigate the impact of tension on engagement in disordered eating behaviors (DEBs) and potential moderating effects of trait emotion regulation in young people from the general population. A subsample of 971 adolescents and young adults from an epidemiological cohort study reported on levels of tension and four different DEBs (skipping eating, restrained eating, eating large amounts of food, loss-of-control-eating) via ecological momentary assessment (EMA), as well as on trait emotion regulation via questionnaire. In multilevel models, momentary tension did not predict levels of subsequent DEBs. However, higher average levels of tension across the EMA period predicted higher levels of all DEBs. No interactions with emotion regulation emerged. Individuals experiencing overall higher levels of tension appear to be more prone to engaging in DEBs.

A neural network underlying cognitive strategies related to eating, weight and body image concerns

Concerns about food intake, weight and body shape can trigger negatively loaded emotions, which may prompt the use of cognitive strategies to regulate these emotional states. A novel fMRI task was developed to assess the neurobehavioral correlates of cognitive strategies related to eating, weight and body image concerns, such as self-criticism, avoidance, rumination, and self-reassurance. Fourteen healthy females were presented audio sentences referring to these conditions and instructed to repeat these internally while engaging their thoughts with the content of food or body images. Participants were asked to report the elicited emotion and rate their performance. All cognitive strategies recruited a network including the inferior and superior frontal gyri, orbitofrontal and anterior cingulate cortex, insula, and dorsal striatum. These brain regions are involved in emotional, reward and inhibitory control processing. Representational similarity analysis revealed distinct patterns of neural responses for each cognitive strategy. Additionally, self-report measures showed that self-criticism was positively associated with superior frontal gyrus (SFG) activation. Self-compassion scores were negatively correlated with activations in the insula and right putamen, while self-reassurance scores were negatively associated with activity in the orbitofrontal cortex. These findings identify a neural network underlying cognitive strategies related to eating, weight and body image concerns, where neurobehavioral correlation patterns depend on the cognitive strategy.

The Willpower Paradox: Possible and Impossible Conceptions of Self-Control

Self-control denotes the ability to override current desires to render behavior consistent with long-term goals. A key assumption is that self-control is required when short-term desires are transiently stronger (more preferred) than long-term goals and people would yield to temptation without exerting self-control. We argue that this widely shared conception of self-control raises a fundamental yet rarely discussed conceptual paradox: How is it possible that a person most strongly desires to perform a behavior (e.g., eat chocolate) and at the same time desires to recruit self-control to prevent themselves from doing it? A detailed analysis reveals that three common assumptions about self-control cannot be true simultaneously. To avoid the paradox, any coherent theory of self-control must abandon either the assumption (a) that recruitment of self-control is an intentional process, or (b) that humans are unitary agents, or (c) that self-control consists in overriding the currently strongest desire. We propose a taxonomy of different kinds of self-control processes that helps organize current theories according to which of these assumptions they abandon. We conclude by outlining unresolved questions and future research perspectives raised by different conceptions of self-control and discuss implications for the question of whether self-control can be considered rational.

Mouse-cursor trajectories reveal reduced contextual influence on decision conflict during delay discounting in anorexia nervosa

OBJECTIVE

The capacity of individuals with anorexia nervosa (AN) to forgo immediate food rewards in their long-term pursuit of thinness is thought to reflect elevated self-control and/or abnormal reward sensitivity. Prior research attempted to capture an increased tendency to delay gratification in AN using delay-discounting tasks that assess how rapidly the subjective value of rewards decreases as a function of time until receipt. However, significant effects were mostly subtle or absent. Here, we tested whether the process leading to such decisions might be altered in AN.

METHOD

We recorded mouse-cursor movement trajectories leading to the final choice in a computerized delay-discounting task (238 trials) in 55 acutely underweight females with AN and pairwise age-matched female healthy controls (HC). We tested for group differences in deviations from a direct choice path, a measure of conflict strength in decision making, and whether group moderated the effect of several predictors of conflict strength (e.g., choice difficulty, consistency). We also explored reaction times and changes in trajectory directions (X-flips).

RESULTS

No group differences in delay-discounting parameters or movement trajectories were detected. However, the effect of the aforementioned predictors on deviations (and to a lesser extent reaction times) was reduced in AN.

DISCUSSION

These findings suggest that while delay discounting and conflict strength in decision making are generally unaltered in AN, conflict strength was more stable across different decisions in the disorder. This might enable individuals with AN to pursue (maladaptive) long-term body-weight goals, because particularly conflicting choices may not be experienced as such.

PUBLIC SIGNIFICANCE

The deviations from a direct path of mouse-cursor movements during a computerized delay-discounting task varied less in people with anorexia nervosa. Assuming such deviations measure decision conflict, we speculate that this increased stability might help people with anorexia nervosa achieve their long-term weight goals, as for them the struggle with the decision to eat high-calorie meals when hungry will be milder, so they would be more likely to skip them.

Explicating the role of amygdala substructure alterations in the link between hypoleptinemia and rumination in anorexia nervosa

OBJECTIVE

The amygdaloid complex plays a pivotal role in emotion processing and has been associated with rumination transdiagnostically. In anorexia nervosa (AN), we previously observed differential reductions of amygdala nuclei volumes (rostral-medial cluster substantially affected) and, in another study, elevated food-/weight-related rumination. Both amygdala volumes and rumination frequency correlated with characteristically suppressed leptin levels in AN. Thus, we hypothesized that amygdala nuclei alterations might be associated with AN-related rumination and potentially mediate the leptin-rumination relationship in AN.

METHODS

Rumination (food-/weight-related) was assessed using ecological momentary assessment for a 14-day period. We employed frequentist and Bayesian linear mixed effects models in females with AN (n = 51, 12-29 years, majority admitted to inpatient treatment) and age-matched healthy females (n = 51) to investigate associations between rostral-medial amygdala nuclei volume alterations (accessory basal, cortical, medial nuclei, corticoamygdaloid transitions) and rumination. We analyzed mediation effects using multi-level structural equation models.

RESULTS

Reduced right accessory basal and cortical nuclei volumes predicted more frequent weight-related rumination in AN; both nuclei fully mediated the effect of leptin on weight-related rumination. In contrast, we found robust evidence for the absence of amygdala nuclei volume effects on rumination in healthy females.

CONCLUSION

This study provides first evidence for the relevance of specific amygdala substructure reductions regarding cognitive symptom severity in AN and points toward novel mechanistic insight into the relationship between hypoleptinemia and rumination, which might involve the amygdaloid complex. Our findings in AN may have important clinical value with respect to understanding the beneficial neuropsychiatric effects of leptin (treatment) in AN and potentially other psychiatric conditions such as depression.

Emotion Dynamics and Emotion Regulation in Anorexia Nervosa: A Systematic Review of Ecological Momentary Assessment Studies

Altered emotion dynamics and emotion regulation (ER) have been indicated in theoretical descriptions of abnormal emotional functioning, which contributes to the development and maintenance of anorexia nervosa (AN). Ecological momentary assessment (EMA) has recently become popular in research on eating disorders. It is a source of new insights into the psychopathology of AN as it enables intensive long-term tracking of everyday experiences and behaviours of individuals through repeated self-reports. The following systematic review aims to synthesize research on the use of EMA when evaluating emotion dynamics and ER in AN. Specific studies were identified with the use of MEDLINE, PsycINFO, and Scopus databases. A supplemental search was performed in reference lists of the relevant publications. As a result, 27 publications were identified and included in the systematic review. The findings from the reviewed studies point to various disturbed components of emotion dynamics as well as to unique associations of maladaptive ER strategies with specific abnormalities in emotion dynamics in AN. Limitations of the studies were discussed as well. An outlook for further research in the field was provided in the last section of the paper.

Increased Habit Frequency in the Daily Lives of Patients with Acute Anorexia Nervosa

Strict eating routines and frequent rigid behavior patterns are commonly observed in patients with anorexia nervosa (AN). A recent theory proposes that while these behaviors may have been reinforced initially, they later become habitual. To date, however, research has been overly focused on eating-disorder (ED)-related habits. Over the course of seven days, we applied an ecological momentary assessment (EMA) to investigate the habit frequency and strength of ED-specific (food intake) and ED-unspecific (hygiene) habits in the daily lives of a sample of n = 57 AN and n = 57 healthy controls (HC). The results of the hierarchical models revealed that habits were significantly more likely in patients compared with HC for both categories, independently. Furthermore, a lower body mass index (BMI) was associated with increased habit frequency in AN. Our study strengthens the habit theory of AN by showing the relevance of habits beyond ED-specific behavioral domains. This also supports the development of innovative therapeutic interventions targeting habitual behavior in EDs.

Real-Life Self-Control Conflicts in Anorexia Nervosa: An Ecological Momentary Assessment Investigation

Background

Individuals with anorexia nervosa (AN) are often thought to show heightened self-control and increased ability to inhibit desires. In addition to inhibitory self-control, antecedent-focused strategies (e.g., cognitive reconstrual—the re-evaluation of tempting situations) might contribute to disorder maintenance and enable disorder-typical, maladaptive behaviors.

Methods

Over a period of 14 days, 40 acutely underweight young female patients with anorexia nervosa (AN) and 40 healthy control (HC) participants reported their affect and behavior in self-control situations via ecological momentary assessment during inpatient treatment (AN) and everyday life (HC). Data were analyzed via hierarchical analyses (linear and logistic modeling).

Results

Conflict strength had a significantly lower impact on self-control success in AN compared to HC. While AN and HC did not generally differ in the number or strength of self-control conflicts or in the percentage of self-control success, AN reported self-controlled behavior to be less dependent on conflict strength.

Conclusions

While patients with AN were not generally more successful at self-control, they appeared to resolve self-control conflicts more effectively. These findings suggest that the magnitude of self-control conflicts has comparatively little impact on individuals with AN, possibly due to the use of antecedent-focused strategies. If confirmed, cognitive-behavioral therapy might focus on and help patients to exploit these alternative self-control strategies in the battle against their illness.

The mediating role of self-criticism, experiential avoidance and negative urgency on the relationship between ED-related symptoms and difficulties in emotion regulation

OBJECTIVE

Difficulties in emotion regulation are thought to play a transdiagnostic role across eating disorders (ED). In the current study, we explored with a path analysis the mediating role of self-criticism, experiential avoidance and negative urgency on the relationship between ED-related symptoms and dimensions of difficulties in emotion regulation.

METHOD

Participants were 103 female outpatients recruited at a Portuguese ED hospital unit, diagnosed with an ED, aged 14-60 years old (M = 28.0, SD = 10.5), body mass index (BMI) ranging from 11.72 to 39.44 (M = 20.1, SD = 5.4).

RESULTS

The path analysis resulted in a model with an adequate fit to the data (SRMR = 0.05; RMSEA = 0.07 [0.00, 0.12], PCLOSE = 0.269; TLI = 0.97; IFI = 0.99; GFI = 0.95). A final model in which the relationship between ED-related symptoms and dimensions of difficulties in emotion regulation was mediated by self-criticism, experiential avoidance and negative urgency, accounted for a variance of 71% for strategies, 57% for non-acceptance, 62% for impulses, 56% for goals and 20% for clarity.

CONCLUSION

Results suggest that self-criticism, experiential avoidance and negative urgency, combined, are relevant in the relationship between ED-related symptoms and difficulties in emotion regulation. ED treatment and emotion regulation skills may be enhanced through the inclusion of specific components that target self-criticism, experiential avoidance and negative urgency, as they become prominent during the therapeutic process.

The Role of Emotion Regulation in Eating Disorders: A Network Meta-Analysis Approach

Background

Previous theoretical models and reviews have documented a strong connection between emotion dysregulation eating disorder (ED) psychopathology among the general and clinical populations. The aim of this review was to build on this previous work by conducting a network meta-analysis to explore associations between adaptive and maladaptive emotion regulation strategies and ED psychopathology trans-diagnostically across the ED spectrum to identify areas of emotion dysregulation that have the strongest association with symptomatology.

Methodology

A total of 104 studies were included in the meta-analysis and correlation coefficient representing the associations between specific emotion regulation strategies and ED symptomatology were extracted. We ran a Bayesian random effects network meta-analysis and the initial network was well-connected with each emotion regulation strategy being linked to at least one other strategy. We also conducted a network meta-regression to explore whether between-study differences in body mass index (BMI), age, and whether the sample consisted of solely female participants explained any possible network inconsistency.

Results

The network meta-analysis revealed that ruminations and non-acceptance of emotions were most closely associated with ED psychopathology. There was no significant network inconsistency but two comparisons approached significance and thus meta-regressions were conducted. The meta-regressions revealed a significant effect of BMI such that the associations between different emotion regulation strategies and ED symptomatology were weaker among those with low BMI.

Discussion

The present findings build on previous work and highlight the role of rumination and difficulties with accepting emotions as key emotion regulation difficulties in EDs. Additionally, the finding that the associations were weaker among ED patients with low BMI may point toward a complex relationship between ED behaviors and emotion regulation. Taken together, our findings call for interventions that target emotion regulation, specifically rumination and difficulties accepting emotions, in the treatment of EDs.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021249996, PROSPERO, identifier: CRD42021249996.

The Problem of Appetite Loss After Major Abdominal Surgery

Objective:

To systematically review the problem of appetite loss after major abdominal surgery.

Summary of Background Data:

Appetite loss is a common problem after major abdominal surgery. Understanding of etiology and treatment options is limited.

Methods:

We searched Medline, Cochrane Central Register of Controlled Trials, and Web of Science for studies describing postoperative appetite loss. Data were extracted to clarify definition, etiology, measurement, surgical influence, pharmacological, and nonpharmacological treatment. PROSPERO registration ID: CRD42021224489.

Results:

Out of 6144 articles, we included 165 studies, 121 of which were also analyzed quantitatively. A total of 19.8% were randomized, controlled trials (n = 24) and 80.2% were nonrandomized studies (n = 97). The studies included 20,506 patients undergoing the following surgeries: esophageal (n = 33 studies), gastric (n = 48), small bowel (n = 6), colon (n = 27), rectal (n = 20), hepatobiliary (n = 6), and pancreatic (n = 13). Appetite was mostly measured with the Quality of Life Questionnaire of the European Organization for Research and Treatment of Cancer (EORTC QLQ C30, n = 54). In a meta-analysis of 4 randomized controlled trials gum chewing reduced time to first hunger by 21.2 hours among patients who had bowel surgery. Other reported treatment options with positive effects on appetite but lower levels of evidence include, among others, intravenous ghrelin administration, the oral Japanese herbal medicine Rikkunshito, oral mosapride citrate, multidisciplin-ary-counseling, and watching cooking shows. No studies investigated the effect of well-known appetite stimulants such as cannabinoids, steroids, or megestrol acetate on surgical patients.

Conclusions:

Appetite loss after major abdominal surgery is common and associated with increased morbidity and reduced quality of life. Recent studies demonstrate the influence of reduced gastric volume and ghrelin secretion, and increased satiety hormone secretion. There are various treatment options available including level IA evidence for postoperative gum chewing. In the future, surgical trials should include the assessment of appetite loss as a relevant outcome measure.

Intact neural and behavioral correlates of emotion processing and regulation in weight-recovered anorexia nervosa: a combined fMRI and EMA study

Altered emotion processing and regulation mechanisms play a key role in eating disorders. We recently reported increased fMRI responses in brain regions involved in emotion processing (amygdala, dorsolateral prefrontal cortex) in acutely underweight anorexia nervosa (AN) patients while passively viewing negatively valenced images. We also showed that patients' ability to downregulate activity elicited by positively valenced pictures in a brain region involved in reward processing (ventral striatum) was predictive of worse outcomes (increased rumination and negative affect). The current study tries to answer the question of whether these alterations are only state effects associated with undernutrition or whether they constitute a trait characteristic of the disorder that persists after recovery. Forty-one individuals that were weight-recovered from AN (recAN) and 41 age-matched healthy controls (HC) completed an established emotion regulation paradigm using negatively and positively valenced visual stimuli. We assessed behavioral (arousal) and fMRI measures (activity in the amygdala, ventral striatum, and dorsolateral prefrontal cortex) during emotion processing and regulation. Additionally, measures of disorder-relevant rumination and affect were collected several times daily for 2 weeks after scanning via ecological momentary assessment. In contrast to our previous findings in acute AN patients, recAN showed no significant alterations either on a behavioral or neural level. Further, there were no associations between fMRI responses and post-scan momentary measures of rumination and affect. Together, these results suggest that neural responses to emotionally valenced stimuli as well as relationships with everyday rumination and affect likely reflect state-related alterations in AN that improve following successful weight-recovery.

Youth Psychopathology in Daily Life: Systematically Reviewed Characteristics and Potentials of Ecological Momentary Assessment Applications

Traditionally, symptoms of youth psychopathology are assessed with questionnaires, clinical interviews, or laboratory observations. Ecological Momentary Assessment (EMA) could be a particularly valuable additional methodology, since EMA enables examining the daily lives of youths near real-time, considering fluctuations and specific contexts of symptoms. This systematic review aimed to review the characteristics of current EMA applications and to provide a synthesis of their potential in studying youth psychopathology. Following a systematic search in PsycInfo and Medline, we identified 50 studies in clinical samples. Most studies used EMA to examine fluctuations in symptoms, affect, and behavior, and the relation with contextual factors. EMA was also used to investigate interactions between parents and their children over time, and to monitor and predict treatment response. EMA appeared feasible in youth and could provide valuable insights that contribute to understanding youth psychopathology. Benefits, gaps, and suggestions for future research and clinical practice are discussed.

How deep is your thought? The relations between intolerance of uncertainty, worry and weight and shape concerns in adolescent girls with anorexia nervosa

BACKGROUND

Inherent to anorexia nervosa are repetitive thoughts about weight and shape. Growing research suggests the relevance of intolerance of uncertainty and worry in maintaining these types of repetitive thoughts. The relation between these cognitive processes and weight and shape concerns in adolescent girls with anorexia nervosa is understudied. This study investigated associations between prospective (desire for predictability) and inhibitory (uncertainty paralysis) intolerance of uncertainty, and weight and shape concerns and the mediating role of worry in these associations.

METHODS

In a cross-sectional study, 93 adolescent girls with anorexia nervosa completed questionnaires measuring the variables of interest. A mediation model with worry as a mediator between inhibitory and prospective intolerance of uncertainty and weight and shape concerns was tested.

RESULTS

A total and direct effect of inhibitory intolerance of uncertainty on weight and shape concerns was found. Worry did not mediate this relation.

CONCLUSIONS

These results confirm the importance of inhibitory intolerance of uncertainty in adolescent girls with anorexia nervosa, more specifically to weight and shape concerns. This group may benefit from intervention strategies targeting intolerance of uncertainty. General worry seems less relevant to weight and shape concerns in adolescent girls with anorexia nervosa. Adolescent girls with anorexia nervosa often experience repetitive thoughts about weight and shape. Growing research suggests the relevance of intolerance of uncertainty and worry in maintaining these types of repetitive thoughts. Intolerance of uncertainty is defined as the incapacity to tolerate uncertainty and is often divided into two components; prospective intolerance of uncertainty (desire for predictability) and inhibitory intolerance of uncertainty (uncertainty paralysis). The relation between intolerance of uncertainty, worry and weight and shape concerns in adolescent girls with anorexia nervosa is understudied. This study aims to investigate study relations between prospective and inhibitory intolerance of uncertainty, worry, and weight and shape concerns. A total of 93 adolescent girls with anorexia nervosa completed three questionnaires, measuring prospective and inhibitory intolerance of uncertainty worry, and weight and shape concerns, respectively. The results of this study confirmed the importance of inhibitory intolerance of uncertainty in adolescent girls with anorexia nervosa, more specifically to weight and shape concerns. This group may benefit from intervention strategies targeting intolerance of uncertainty. General worry seems less relevant to weight and shape concerns in adolescent girls.

Multi-state modeling of thought-shape fusion using ecological momentary assessment

Body dissatisfaction (BD) and preoccupation with thoughts of food (PTF) are intertwined and are components of thought-shape fusion. Thought-shape fusion describes the process by which PTF lead to beliefs about weight and shape. To study thought-shape fusion in daily life and explore various transitions between BD and PTF, 30 women with binge eating completed ecological momentary assessment for 14 days. BD and PTF were assessed using continuous rating scales at each prompt. Multi-state modeling, which analyzes micro-temporal transitions between discrete states, was used to examine transitions among four states created with BD and PTF ratings. The four states included low BD/low PTF, low BD/high PTF, high BD/low PTF, and high BD/high PTF. Affect and disordered eating were examined as covariates of state transitions. Results showed high BD states were self-perpetrating, such that when in high BD states, transition to low BD states were less likely. Regarding covariates, positive affect buffered against maladaptive transitions whereas negative affect and disordered eating increased risk. Findings highlighted high BD states as influential, and negative affect and disordered eating as risk factors and positive affect as preventive. This study enhances theory of thought-shape fusion and implicates transitions from BD to PTF as possible underlying transitions.

Examining prospective mediational relationships between momentary rumination, negative affect, and binge eating using ecological momentary assessment

BACKGROUND

Rumination is linked to negative affect (NA), and there is accumulating support for an association between rumination and eating disorder (ED) behaviors. However, no research has examined the dynamic interrelationships between negative affect, rumination, and binge eating in naturalistic settings.

METHODS

The present study used ecological momentary assessment (EMA) to assess the hypotheses that momentary rumination would mediate relationships between NA and binge eating, and momentary NA would mediate relationships between rumination and binge eating. Given that rumination may be focused on weight, shape, and food in ED samples, models were examined separately for general and ED-specific rumination. Forty women completed a 10-day EMA protocol that included measures of NA, general and ED-specific rumination, and binge eating.

RESULTS

Multilevel mediation models indicated significant within-subjects indirect effects, such that momentary general rumination mediated the association between NA and binge eating, and NA also mediated the association between general but not ED-specific rumination and binge eating. Between-subjects effects indicated women with higher overall NA reported greater ED-specific rumination, which was associated with greater binge eating.

LIMITATIONS

The study was limited by a modest sample size, and the design precludes causal inferences.

CONCLUSIONS

Results highlight the momentary interplay between rumination and NA as a mechanism underlying binge eating, as well as the specificity of ruminative thought content in relationship to binge eating. Future work is needed to address the construct of rumination in the context of eating disorder interventions.

Repetitive Negative Thinking and Eating Disorders: A Meta-Analysis of the Role of Worry and Rumination

The role of worry and rumination in eating disorders (EDs) is controversial. This meta-analysis of the literature is aimed at clarifying the relationship between repetitive negative thinking (RNT) and EDs. In accordance with the PRISMA criteria, a comprehensive search of the literature was conducted on PubMed and PsycInfo from inception to March 2021. Search terms: “eating disorder/anorexia/bulimia/binge eating disorder” AND “worry/rumination/brooding/repetitive thinking”. A manual search of reference lists was also run. Forty-three studies were included. RNT was found to be associated with anorexia, bulimia, and binge eating disorder. A moderating effect was found for “presence/absence ED diagnosis” and “subtype of ED symptom”. ED patients showed higher RNT than the general population. No differences were observed for age or between worry and rumination in the magnitude of their association with EDs.

The costs of over-control in anorexia nervosa: evidence from fMRI and ecological momentary assessment

A growing body of evidence suggests that a high level of self-control may, despite its positive effects, influence cognitive processing in an unfavorable manner. However, the affective costs of self-control have only rarely been investigated. Anorexia nervosa (AN) is an eating disorder that is often characterized by excessive self-control. Here, we used fMRI to explore whether over-control in AN may have negative affective consequences. 36 predominantly adolescent female AN patients and 36 age-matched healthy controls (HC) viewed negative and neutral pictures during two separate fMRI sessions before and after 10 min of rest. We tested whether abnormally elevated neural activity during the initial presentation in a brain region broadly implicated in top-down control, the dorsolateral prefrontal cortex (dlPFC), could predict subsequent activation in limbic areas relevant to bottom-up affective processing. Using ecological momentary assessment (EMA), we also tested for associations between the aforementioned neuroimaging markers and negative affective states in the two weeks following the experiment. fMRI data revealed that higher initial activation of the dlPFC in AN predicted increased amygdala reactivity during the second fMRI session, which in turn was related to increased self-reported tension during two weeks following the scan. These data suggest that over-control in AN patients may come at a cost including negative affective states on a short (minutes) as well as a longer time scale (days). This mechanism may significantly contribute to the persistence of AN.

From Desire to Dread-A Neurocircuitry Based Model for Food Avoidance in Anorexia Nervosa

Anorexia nervosa is a severe psychiatric illness associated with food avoidance. Animal models from Berridge et al. over the past decade showed that environmental ambience, pleasant or fear inducing, can trigger either appetitive (desire) or avoidance (dread) behaviors in animals via frontal cortex, nucleus accumbens dopamine D1 and D2 receptors, and hypothalamus. Those mechanisms could be relevant for understanding anorexia nervosa. However, models that translate animal research to explain the psychopathology of anorexia nervosa are sparse. This article reviews animal and human research to find evidence for whether this model can explain food avoidance behaviors in anorexia nervosa. Research on anorexia nervosa suggests fear conditioning to food, activation of the corticostriatal brain circuitry, sensitization of ventral striatal dopamine response, and alterations in hypothalamic function. The results support the applicability of the animal neurocircuitry derived model and provide directions to further study the pathophysiology that underlies anorexia nervosa.

Cognitive Function in Adults with Enduring Anorexia Nervosa

Anorexia Nervosa (AN) is a severe and often enduring disorder characterized by restriction of food intake, low body weight, fear of weight gain, and distorted body image. Investigations on cognition performance in AN patients have yielded conflicting results. Using an established and sensitive computerized cognitive test battery, we aimed to assess core aspects of cognitive function, including attention span, information processing, reasoning, working and episodic memory, in AN patients and controls. Patients were recruited from the Danish Prospective Longitudinal all-comer inclusion study in Eating Disorders (PROLED). Included were 26 individuals with AN and 36 healthy volunteers (HV). All were tested with CogTrack (an online cognitive assessment system) at baseline, and AN patients were tested again at a follow-up time point after weight increase (n = 13). At baseline, AN patients showed faster reaction times in the attention tasks, as well as increased accuracy in grammatical reasoning compared to HV. There were no differences in cognitive function between AN patients and HV in the other cognitive domains measured (sustained attention, working and episodic memory, speed of retrieval, and speed of grammatical reasoning). No differences were visible in the AN sample between baseline and follow-up. Performance did not correlate with any clinical variables in the AN sample. These findings supplement results from other studies suggesting increased concentration and reasoning accuracy in patients suffering from AN, who showed increased performance in cognitive tasks despite their illness.

Smartphone-Based Self-Monitoring, Treatment, and Automatically Generated Data in Children, Adolescents, and Young Adults With Psychiatric Disorders: Systematic Review

BACKGROUND

Psychiatric disorders often have an onset at an early age, and early identification and intervention help improve prognosis. A fine-grained, unobtrusive, and effective way to monitor symptoms and level of function could help distinguish severe psychiatric health problems from normal behavior and potentially lead to a more efficient use of clinical resources in the current health care system. The use of smartphones to monitor and treat children, adolescents, and young adults with psychiatric disorders has been widely investigated. However, no systematic review concerning smartphone-based monitoring and treatment in this population has been published.

OBJECTIVE

This systematic review aims at describing the following 4 features of the eligible studies: (1) monitoring features such as self-assessment and automatically generated data, (2) treatment delivered by the app, (3) adherence to self-monitoring, and (4) results of the individual studies.

METHODS

We conducted a systematic literature search of the PubMed, Embase, and PsycInfo databases. We searched for studies that (1) included a smartphone app to collect self-monitoring data, a smartphone app to collect automatically generated smartphone-based data, or a smartphone-based system for treatment; (2) had participants who were diagnosed with psychiatric disorders or received treatment for a psychiatric disorder, which was verified by an external clinician; (3) had participants who were younger than 25 years; and (4) were published in a peer-reviewed journal. This systematic review was reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The risk of bias in each individual study was systematically assessed.

RESULTS

A total of 2546 unique studies were identified through literature search; 15 of these fulfilled the criteria for inclusion. These studies covered 8 different diagnostic groups: psychosis, eating disorders, depression, autism, self-harm, anxiety, substance abuse, and suicidal behavior. Smartphone-based self-monitoring was used in all but 1 study, and 11 of them reported on the participants' adherence to self-monitoring. Most studies were feasibility/pilot studies, and all studies on feasibility reported positive attitudes toward the use of smartphones for self-monitoring. In 2 studies, automatically generated data were collected. Three studies were randomized controlled trials investigating the effectiveness of smartphone-based monitoring and treatment, with 2 of these showing a positive treatment effect. In 2 randomized controlled trials, the researchers were blinded for randomization, but the participants were not blinded in any of the studies. All studies were determined to be at high risk of bias in several areas.

CONCLUSIONS

Smartphones hold great potential as a modern, widely available technology platform to help diagnose, monitor, and treat psychiatric disorders in children and adolescents. However, a higher level of homogeneity and rigor among studies regarding their methodology and reporting of adherence would facilitate future reviews and meta-analyses.

Body image in and out of the lab: Correspondence between lab-based attentional bias data and body shape dissatisfaction experiences in daily life

Accumulating lab-based studies have identified attentional biases in processing of negative appearance-related information among individuals with elevated trait body shape and weight dissatisfaction (BD). How these biases translate into experiences of BD in daily life remains unclear and, hence, was the focus of the present study. Thirty-eight women aged between 18-40 years completed a baseline survey and modified dot-probe task with both fat and thin appearance-related stimuli in a laboratory setting. Participants also downloaded a smartphone app that prompted them 10 times per day for 7 days to rate current body dissatisfaction. Results revealed that heightened BD in daily life tended to be transitory, and followed by a substantially lower rating of BD by the next survey (∼1-2 h later). For individuals with elevated trait BD and facilitated attention towards thin body images, this reduction in state BD was more gradual. Surprisingly, delayed disengagement towards thin body images was associated with greater reduction in state BD. Consistent with the hypothesis, moderating effects were not observed when initial state BD level was low. Susceptibility for immediate, short-term attentional biases towards appearance-related information may be a vulnerability factor for the prolonged persistence of negative body image experiences in daily life.

A naturalistic investigation of cognitive-affective dysfunction in anorexia nervosa: The role of inefficiency

OBJECTIVE

Research has shown that rumination and negative affect are elevated in patients with anorexia nervosa (AN), but the underlying origins remain unclear. Drawing from the theoretical framework of the Goal Progress Theory of rumination, we propose that heightened feelings of "inefficiency" (i.e., low self-efficacy) in AN might play an important role in these dysfunctional cognitive-affective processes.

METHOD

Thirty-two weight-recovered participants with a history of AN and 32 healthy control participants filled out questionnaires regarding rumination and affect six times a day over a period of 2 weeks via ecological momentary assessment in real-life.

RESULTS

Analyses via hierarchical as well as conceptual process modeling suggest that while inefficiency is generally associated with more rumination and negative affect, additional amplifying mechanisms between these variables exist specifically in recovered participants with a history of AN.

DISCUSSION

Inefficiency as a core aspect of AN appears to trigger dysfunctional cognitive-affective processes which may contribute to vulnerability for AN.

Testing an emotion regulation model of physical activity in adolescents with anorexia nervosa: A pilot ecological momentary assessment

OBJECTIVE

Adolescents with anorexia nervosa (AN) often show increased levels of exercise and physical activity. Psychological models suggest that physical activity in AN might attenuate momentary negative affect. However, this has not been directly tested in adolescents with AN, and it remains unclear whether this is a distinct mechanism of physical activity in AN compared with healthy controls (HCs).

METHOD

In a 1-day ecological momentary assessment, 32 adolescent inpatients with AN and 30 HCs responded to hourly questions on momentary affect while wearing an actigraph to objectively assess physical activity.

RESULTS

Linear mixed models identified that adolescents with AN experienced more aversive tension, more negative affect, and less positive affect throughout the day than HCs. Preliminary evidence for a momentary association of higher levels of physical activity with positive affect were found for both groups, whereas higher levels of physical activity were associated with less negative affect in adolescents with AN only. When correcting for multiple testing, interactions did not hold statistical significance.

DISCUSSION

Our results indicate a down-regulation effect of physical activity on negative affect for AN and a more general up-regulation effect of positive affect. However, our sample size was small, and replication of our findings is needed.

Body image states in everyday life: Evidence from ecological momentary assessment methodology

This review highlights the contributions of Professor Thomas Cash to the scholarship of body image experiences in daily life, including his influence on subsequent research in this field. Cash's arguments for capturing a broad range of state-based body image experiences have been heeded, with recent studies exploring positive body image constructs as well as the more studied negative body image experiences. Appearance comparisons are the most commonly studied contextual influence on body image, and they seem to have a consistent effect. However, the experiences of body image in sexual contexts, and among adolescents, those who are pregnant, or have other physical characteristics that may increase the salience of appearance warrant further attention. Findings generally support Cash's contention that trait body image relates to likelihood and level of experience of body image in daily life, though the moderating effects of trait aspects on state-based relationships remains unclear. The discussion concludes with consideration of the impact of assessment schedules on obtained results. It is also discussed how accumulated knowledge regarding state-based body image experiences may be leveraged in treatment contexts, particularly in light of clear evidence that repeated assessment of body image in daily life increases self-awareness of one's body image characteristics.

Obsessions are strongly related to eating disorder symptoms in anorexia nervosa and atypical anorexia nervosa

Anorexia nervosa (AN) and obsessive-compulsive disorder (OCD) are highly comorbid. However, little research has examined which specific cognitive-behavioral aspects (e.g., checking, obsessing) of OCD are most relevant in those with AN. Furthermore, there is no research examining aspects of OCD in Atypical AN. The current two studies (N = 139 and N = 115 individuals diagnosed with AN/Atypical AN) examined a) which aspects of OCD were most related to AN symptomatology and b) if there were differences in OCD between individuals diagnosed with AN vs Atypical AN. We found that obsessing was most related to AN symptoms. We also found that there were no substantial significant differences between AN and Atypical AN. These findings add to the literature suggesting minimal differences between AN and Atypical AN, specifically regarding OCD symptomatology. These findings clarify that obsessions (rather than compulsions) may be the specific aspect of OCD most warranting treatment intervention in AN and Atypical AN.

Emotion regulation strategy use and eating disorder symptoms in daily life

OBJECTIVE

Emotion regulation is posited to be disrupted in eating disorders, but studies have yet to examine the linkage between eating disorder symptoms and emotion regulation strategy use in daily life. We conducted an experience sampling study investigating associations between trait-level difficulties with emotion regulation, daily emotion regulation strategy use, and eating disorder symptoms in daily life.

METHOD

Fifty-three undergraduate women completed a trait-level measure of difficulties with emotion regulation, then reported their use of emotion regulation strategies four times per day for seven days. At the end of each day, they also reported daily disordered eating symptoms and behaviors.

RESULTS

Reduced access to emotion regulation strategies at the trait-level was associated with dimensional eating disorder symptoms and food restriction across the study period. In addition, greater use of maladaptive strategies and attentional deployment and less use of adaptive strategies on a given day were associated with a higher likelihood of food restriction on that day. Moderation analyses based on baseline eating disorder symptoms indicated that associations were consistent across symptom severity.

CONCLUSIONS

These findings suggest that certain eating disorder symptoms are associated with difficulties in regulating emotions at the trait-level and in daily life.

From Ecological Momentary Assessment (EMA) to Ecological Momentary Intervention (EMI): Past and Future Directions for Ambulatory Assessment and Interventions in Eating Disorders

PURPOSE OF REVIEW

Ambulatory assessment methods, including ecological momentary assessment (EMA), have often been used in eating disorders (EDs) to assess the type, frequency, and temporal sequencing of ED symptoms occurring in naturalistic environments. Relatedly, growing research in EDs has explored the utility of ecological momentary interventions (EMIs) to target ED symptoms. The aims of the present review were to (1) synthesize recent literature pertaining to ambulatory assessment/EMA and EMI in EDs, and (2) identify relevant limitations and future directions in these domains.

RECENT FINDINGS

With respect to ambulatory assessment and EMA, there has been substantial growth in the expansion of constructs assessed with EMA, the exploration of state- vs. trait-level processes, integration of objective and passive assessment approaches, and consideration of methodological issues. The EMI literature in EDs also continues to grow, though most of the recent research focuses on mobile health (mHealth) technologies with relatively minimal EMI components that adapt to momentary contextual information. Despite these encouraging advances, there remain several promising areas of ambulatory assessment research and clinical applications in EDs going forward. These include integration of passive data collection, use of EMA in treatment evaluation and design, evaluation of dynamic system processes, inclusion of diverse samples, and development and evaluation of adaptive, tailored EMIs such as just-in-time adaptive interventions. While much remains to be learned in each of these domains, the continual growth in mobile technology has potential to facilitate and refine our understanding of the nature of ED psychopathology and ultimately improve intervention approaches.

Editorial: To Eat or Not to Eat: Advancing the Neuroscience of Hedonic Versus Controlled Eating Across Weight and Eating Disorders

Excessive weight and obesity, especially with childhood onset, is associated with long-term morbidity and mortality and places a major burden on the health care system. In the United States, 17% of children and adolescents are obese (32% overweight). By adulthood, the number rises to 34% or even 68% when also considering overweight individuals.¹ Conventional nonsurgical treatments are often ineffective, and weight loss achieved with behaviorally oriented therapy programs is usually small (∼5%) and short-lived.² A better understanding of the associated psychological mechanisms and their neurobiological underpinnings may allow for the development of more efficient, potentially brain-based, therapeutic interventions. A growing number of human functional magnetic resonance imaging (fMRI) studies point to alterations in reward-related corticostriatal circuity and the hypothalamus, a key area in energy homeostasis.³ Recent studies have analyzed resting state functional connectivity (rsFC), a technique sensitive to changes in the interaction between distant brain regions, which is particularly advantageous in clinical samples, as it requires little compliance and as scanning time is relatively short.

Editorial: Connecting the Nodes of Altered Brain Network Organization in Eating Disorders

Two prevalent eating disorders (ED) in adolescence are anorexia nervosa (AN) and bulimia nervosa (BN). AN is characterized primarily by an extensive restriction of energy intake leading to significantly low body weight. In contrast, the cardinal symptom of BN is uncontrolled eating of an abnormally large amount of food, followed by compensatory behavior to avoid weight gain (eg, self-induced vomiting or laxative abuse). Despite these differences and the fact that individuals with BN are usually of normal weight, patients with both disorders have an abnormal preoccupation with body weight and shape,¹ often in the form of distressing ruminations.^2,3 Left untreated, body image distortion and associated extreme eating/purging habits often have severe and life-long physical, social and psychological consequences. A better understanding of the neurobiological substrates of clinical symptoms may help to improve therapeutic interventions and outcome.⁴.

Rumination in anorexia nervosa: Cognitive-affective and neuroendocrinological aspects

Rumination about body weight/figure as well as food is common in patients with Anorexia Nervosa (AN) and may be a maintenance factor of the disorder. While rumination can generally be considered as a cognitive-affective process, food-related rumination may be driven primarily by a physiological response to undernutrition. In the current longitudinal study, we integrate ecological momentary assessment of rumination and affect and, as a biological marker of undernutrition, plasma leptin levels collected from 33 AN patients. At the very acute stage and again after short-term weight-restoration patients answered short questionnaires six times per day over two weeks. Analyses via hierarchical linear modelling confirmed that rumination is closely linked to affect in AN before and after weight-restoration. Rumination about food decreased during weight-restoration and was correlated with leptin levels. In contrast, rumination about body weight/figure was not linked to leptin, persisted after weight gain, and showed stronger connections with affect. This suggests that rumination about body weight/figure seems to be a cognitive-affective aspect of the disorder, but food-related rumination may need to be considered from a physiological perspective. It is possible that food-related ruminative thoughts reflect a physiological symptom induced by undernutrition, similar to well-described leptin-associated changes in physical activity.

Rumination and eating disorder psychopathology: A meta-analysis

Rumination is a cognitive process involving repetitive thoughts about negative experiences and emotions and is associated with psychopathology. Rumination has been implicated in mood and anxiety disorders, and there is a growing body of research on rumination in relation to eating disorder (ED) psychopathology. The current meta-analytic review focused on the literature addressing rumination and ED psychopathology. A comprehensive search process identified 38 studies, which primarily used cross-sectional designs with non-clinical samples. Results demonstrated that rumination was concurrently (r = 0.33) and prospectively (r = 0.22-0.23) associated with ED psychopathology, and that groups with ED psychopathology evidenced higher levels of rumination compared to non-ED control groups (g = 0.95), though no significant differences in rumination were observed when comparing anorexia nervosa to bulimia nervosa groups (g = 0.09). In addition, a narrative review of five experimental studies suggested that rumination in response to ED-related stimuli was related to increased negative affect and negative body-related cognitions across clinical and non-clinical samples. The type of rumination and sample population emerged as moderators of effect sizes, such that larger effects were observed among samples using ED-specific measures of rumination and heterogeneous samples compared to only non-clinical samples. Taken together, this literature demonstrates that rumination is a salient process in ED psychopathology, though the literature is characterized by methodological limitations and the need for more fully elaborated theories on the role of rumination in EDs. Findings are discussed in the context of existing models of rumination and ED psychopathology, with suggestions for future research in this area.

The real-life costs of emotion regulation in anorexia nervosa: a combined ecological momentary assessment and fMRI study

Regulation of emotions is necessary for successful attainment of short-term and long-term goals. However, over-regulation may also have its costs. In anorexia nervosa (AN), forgoing food intake despite emaciation and endocrine signals that promote eating is an example of "too much" self-control. Here we investigated whether voluntary emotion regulation in AN patients comes with associated disorder-relevant costs. Thirty-five patients with acute AN and thirty-five age-matched healthy controls (HCs) performed an established emotion regulation paradigm during functional magnetic resonance imaging after an overnight fast. The task required reducing emotions induced by positively valenced pictures via distancing. We calculated a neural regulation score from responses recorded in a reward-related brain region of interest (ventral striatum; VS) by subtracting activation measured on "positive distance" trials from that elicited under the "positive watch" (baseline) condition. Complementing the imaging data, we used ecological momentary assessment (EMA) to probe disorder-related rumination and affect six times/day for 2 weeks following the scanning session. The neural regulation score indicating reduced VS activation during emotion regulation was used as a predictor in hierarchical linear models with EMA measures as outcomes. No group differences in neural activity were found for the main contrasts of the task. However, regulation of VS activity was associated with increased body-related rumination and increased negative affect in AN, but not in HC. In line with this finding, correlational analysis with longitudinal BMI measurements revealed a link between greater VS regulation and poorer treatment outcome after 60 and 90 days. Together, these results identify a neural correlate of altered emotion regulation in AN, which seems to be detrimental to psychological well-being and may interfere with recovery.

The Role of Working Memory for Cognitive Control in Anorexia Nervosa versus Substance Use Disorder

Prefrontal cortex executive functions, such as working memory (WM) interact with limbic processes to foster impulse control. Such an interaction is referred to in a growing body of publications by terms such as cognitive control, cognitive inhibition, affect regulation, self-regulation, top-down control, and cognitive–emotion interaction. The rising trend of research into cognitive control of impulsivity, using various related terms reflects the importance of research into impulse control, as failure to employ cognitions optimally may eventually result in mental disorder. Against this background, we take a novel approach using an impulse control spectrum model – where anorexia nervosa (AN) and substance use disorder (SUD) are at opposite extremes – to examine the role of WM for cognitive control. With this aim, we first summarize WM processes in the healthy brain in order to frame a systematic review of the neuropsychological, neural and genetic findings of AN and SUD. In our systematic review of WM/cognitive control, we found n = 15 studies of AN with a total of n = 582 AN and n = 365 HC participants; and n = 93 studies of SUD with n = 9106 SUD and n = 3028 HC participants. In particular, we consider how WM load/capacity may support the neural process of excessive epistemic foraging (cognitive sampling of the environment to test predictions about the world) in AN that reduces distraction from salient stimuli. We also consider the link between WM and cognitive control in people with SUD who are prone to ‘jumping to conclusions’ and reduced epistemic foraging. Finally, in light of our review, we consider WM training as a novel research tool and an adjunct to enhance treatment that improves cognitive control of impulsivity.

A dark past, a restrained present, and an apocalyptic future: time perspective, personality, and life satisfaction among anorexia nervosa patients

BACKGROUND

Despite reporting low levels of well-being, anorexia nervosa patients express temperament traits (e.g., extraversion and persistence) necessary for high levels of life satisfaction. Nevertheless, among individuals without eating disorders, a balanced organization of the flow of time, influences life satisfaction beyond temperamental dispositions. A balanced time perspective is defined as: high past positive, low past negative, high present hedonistic, low present fatalistic, and high future. We investigated differences in time perspective dimensions, personality traits, and life satisfaction between anorexia nervosa patients and matched controls. We also investigated if the personality traits and the outlook on time associated to positive levels of life satisfaction among controls also predicted anorexia patients' life satisfaction. Additionally, we investigated if time perspective dimensions predicted life satisfaction beyond personality traits among both patients and controls.

METHOD

A total of 88 anorexia nervosa patients from a clinic in the West of Sweden and 111 gender-age matched controls from a university in the West of Sweden participated in the Study. All participants responded to the Zimbardo Time Perspective Inventory, the Ten Item Personality Inventory, and the Temporal Satisfaction with Life Scale.

RESULTS

A t-test showed that patients scored higher in the past negative, the present fatalistic, and the future dimensions, lower in the past positive and the present hedonistic dimensions, higher in conscientiousness, extraversion, and agreeableness, and lower in life satisfaction. Regression analyses showed that life satisfaction was predicted by openness to experience and emotional stability for controls and by emotional stability among patients. When time dimensions were entered in the regression, emotional stability and the past negative and past positive time dimensions predicted life satisfaction among controls, but only the past positive and present hedonistic time dimensions predicted life satisfaction among patients.

CONCLUSION

Anorexia patients were less satisfied with life despite being more conscientious, social, and agreeable than controls. Moreover, compared to controls, patients had an unbalanced time perspective: a dark view of the past (i.e., high past negative), a restrained present (i.e., low present hedonistic) and an apocalyptic view of the future (i.e., high present fatalistic). It is plausible to suggest that, therapeutic interventions should focus on empowering patients to cultivate a sentimental and positive view of the past (i.e., high past positive) and the desire to experience pleasure without concern for future consequences (i.e., high present hedonistic) so that they can make self-directed and flexible choices for their own well-being. Such interventions might have effects on life satisfaction beyond the patients' temperamental disposition.

Rumination in Patients with Binge-Eating Disorder and Obesity: Associations with Eating-Disorder Psychopathology and Weight-bias Internalization

Overvaluation of shape and weight in binge-eating disorder (BED) is associated with greater eating-disorder psychopathology and greater weight-bias internalization, which are-in turn-associated with poorer mental and physical health. Little is known, however, about the significance of other cognitive processes, such as rumination, in BED. This study examined rumination and overvaluation of shape/weight with eating-disorder psychopathology and weight-bias internalization among 237 treatment-seeking patients with BED and comorbid obesity. Hierarchical multiple regressions indicated that rumination was associated with eating-disorder psychopathology and weight-bias internalization above and beyond the influence of overvaluation of shape/weight. Findings suggest that, among patients with BED/obesity, rumination is an important cognitive process associated with severity of eating-disorder psychopathology even after accounting for overvaluation of shape/weight. Patients with greater rumination might be more likely to dwell on weight-based discrimination experiences and internalize these negative attitudes. Additional controlled examination could determine whether rumination represents another potential target for BED/obesity treatment. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association.

Reactivity to smartphone-based ecological momentary assessment of depressive symptoms (MoodMonitor): protocol of a randomised controlled trial

BACKGROUND

Ecological momentary assessment (EMA) of mental health symptoms may influence the symptoms that it measures, i.e. assessment reactivity. In the field of depression, EMA reactivity has received little attention. We aim to investigate whether EMA of depressive symptoms induces assessment reactivity. Reactivity will be operationalised as an effect of EMA on depressive symptoms measured by a retrospective questionnaire, and, secondly, as a change in response rate and variance of the EMA ratings.

METHODS

This study is a 12-week randomised controlled trial comprising three groups: group 1 carries out EMA of mood and completes a retrospective questionnaire, group 2 carries out EMA of how energetic they feel and completes a retrospective questionnaire, group 3 is the control group, which completes only the retrospective questionnaire. The retrospective questionnaire (Centre for Epidemiologic Studies Depression scale; CES-D) assesses depressive symptoms and is administered at baseline, 6 weeks after baseline and 12 weeks after baseline. We aim to recruit 160 participants who experience mild to moderate depressive symptoms, defined as a Patient Health Questionnaire (PHQ-9) score of 5 to 15. This study is powered to detect a small between-groups effect, where no clinically relevant effect is defined as the effect size margin -0.25< d <0.25.

DISCUSSION

To our knowledge, this is the first study to investigate whether self-rated EMA of depressive symptoms could induce assessment reactivity among mildly depressed individuals.

TRIAL REGISTRATION

Netherlands Trial Register NTR5803. Registered 12 April 2016. http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=5803 .