Preliminary evidence for a role for impulsivity in cognitive disinhibition in bulimia nervosa

Impact of Impulsivity and Therapy Response in Eating Disorders from a Neurophysiological, Personality and Cognitive Perspective

Impulsivity, as a multidimensional construct, has been linked to eating disorders (EDs) and may negatively impact treatment response. The study aimed to identify the dimensions of impulsivity predicting poor remission of ED symptoms. A total of 37 ED patients underwent a baseline assessment of impulsive personality traits and inhibitory control, including the Stroop task and the emotional go/no-go task with event-related potentials (ERPs) analysis. The remission of EDs symptomatology was evaluated after 3 months of cognitive-behavioral therapy (CBT) and at a 2-year follow-up. Poor remission after CBT was predicted by poor inhibitory control, as measured by the Stroop task. At 2 years, the risk of poor remission was higher in patients with higher novelty seeking, lower inhibitory control in the Stroop and in ERPs indices (N2 amplitudes) during the emotional go/no-go task. The present results highlight inhibitory control negatively impacting both short- and long-term symptomatology remission in ED patients. On the other hand, high novelty seeking and ERPs indices of poor inhibition seem to be more specifically related to long-term remission. Therefore, a comprehensive assessment of the impulsivity dimension in patients with ED is recommended to tailor treatments and improve their efficacy.

An exploratory study of associations between the ICD-11 personality disorder model and eating pathology

BACKGROUND

Recently, the International Classification of Diseases 11th Revision (ICD-11) has introduced a paradigm shift in personality disorder conceptualization. The novel ICD-11 personality disorder model comprises a dimensional assessment of personality dysfunction and five maladaptive personality trait domains. Maladaptive personality plays a central role in eating pathology. Yet, relations between the ICD-11 personality disorder model and eating pathology are, to date, unclear. Thus, this study aimed to explore the bivariate, incremental, and interactive associations of the ICD-11 personality disorder model components with eating pathology domains.

METHODS

A predominantly female (85%) sample of 888 German-speaking community adults completed validated self-report measures of personality dysfunction, the ICD-11 personality trait domains, and five eating pathology domains (drive for thinness, bulimia, body dissatisfaction, orthorexia, binge eating). Bivariate and hierarchical regressions models were used to investigate bivariate, incremental, and interactive relations between the ICD-11 personality disorder model components and eating pathology.

RESULTS

Personality dysfunction and the ICD-11 personality trait domains showed statistically significant bivariate relations with eating pathology. Additionally, personality dysfunction and most ICD-11 personality trait domains displayed incremental links with eating pathology. Finally, the relations of the ICD-11 personality trait domains with eating pathology were largely independent of the severity of personality dysfunction.

CONCLUSIONS

This study indicated that all ICD-11 personality disorder model components are uniquely linked to eating pathology. Beyond maladaptive personality trait domains, the strong and incremental relations of personality dysfunction with eating pathology have potential implications for theory building. Further research using longitudinal designs is needed to evaluate causal links between the ICD-11 personality disorder model components and eating pathology.

Impulsivity and compulsivity in anorexia and bulimia nervosa: A systematic review

This study aimed to systematically appraise cross-sectional research that compared the cognitive performance of individuals in the acute phase of BN and/or AN to HCs on measures of impulsivity and compulsivity. The results of the systematic review showed support for the trans-diagnostic approach to eating disorders. There was no strong evidence to support the characterisation of AN as high in compulsivity (and low in impulsivity), nor to support the characterisation of BN as high in impulsivity (and low in compulsivity). There appeared to be mixed findings for both impulsivity and compulsivity across AN and BN. Results were highly variable due to the heterogeneous tasks used, and lack of replication across studies. There was no consensus amongst the included studies on the most appropriate task and/or outcome measures that should be used to study the constructs of impulsivity and compulsivity.

Emerging Treatments in Eating Disorders

Eating disorders (EDs), including anorexia nervosa, bulimia nervosa, and binge-eating disorder, constitute a class of common and deadly psychiatric disorders. While numerous studies in humans highlight the important role of neurobiological alterations in the development of ED-related behaviors, the precise neural substrate that mediates this risk is unknown. Historically, pharmacological interventions have played a limited role in the treatment of eating disorders, typically providing symptomatic relief of comorbid psychiatric issues, like depression and anxiety, in support of the standard nutritional and psychological treatments. To date there are no Food and Drug Administration-approved medications or procedures for anorexia nervosa, and only one Food and Drug Administration-approved medication each for bulimia nervosa (fluoxetine) and binge-eating disorder (lisdexamfetamine). While there is little primary interest in drug development for eating disorders, postmarket monitoring of medications and procedures approved for other indications has identified several novel treatment options for patients with eating disorders. In this review, I utilize searches of the PubMed and ClinicalTrials.gov databases to highlight emerging treatments in eating disorders.

Behavioral measures and self-report of impulsivity in bipolar disorder: no association between Stroop test and Barratt Impulsiveness Scale

BACKGROUND

Impulsivity as a tendency to act quickly without considering future consequences has been proposed as a dimensional factor in bipolar disorder. It can be measured using behavioral tasks and self-report questionnaires. Previous findings revealed patients to show worse performance on at least one behavioral measure of impulsivity. Additionally, self-reported impulsivity seems to be higher among bipolar patients, both parameters being possibly associated with a more severe course of illness. In this study, our primary aim was to investigate the relationship between these two constructs of impulsivity among bipolar patients.

METHODS

A total of 40 euthymic patients with bipolar disorder (21 female, 22 Bipolar I) and 30 healthy controls were recruited for comprehensive neuropsychological assessment. To assess inhibition control as a behavioral measure of impulsivity, the Stroop Color and Word Test (Stroop) was used. Additionally, both groups completed the Barratt Impulsiveness Scale (BIS) as a self-report of impulsivity. To compare the groups' performance on the Stroop and ratings on the BIS, the non-parametric Mann-Whitney U test was used. Within the bipolar group, we additionally examined the possibility of an association between Stroop performance and BIS total scores using Pearson's Correlation r.

RESULTS

Patients and controls differed significantly on the Stroop and BIS, with patients performing worse on the Stroop and scoring higher on the BIS. However, there was no association between the Stroop and BIS within the bipolar group. As an exploratory analysis, a positive correlation between Stroop performance and number of episodes was found. Further, we detected a statistical trend in the direction of poorer Stroop performance among patients treated with polypharmacy.

CONCLUSIONS

Both difficulties with behavioral inhibition and self-reported impulsivity were observed to be higher in bipolar patients than controls in the current study. However, within the patient group we did not observe an association between patients' behavioral performance and self-report. This indicates that the parameters likely constitute distinct, dimensional factors of bipolar disorder. In future research, studies with larger samples should investigate which of the two markers constitutes the better marker for the illness and is more suitable to differentiate the most severe patients.

Neural signature of behavioural inhibition in women with bulimia nervosa

BACKGROUND

Impaired inhibitory control is considered a behavioural phenotype in patients with bulimia nervosa. However, the underlying neural correlates of impaired general and food-specific behavioural inhibition are largely unknown. Therefore, we investigated brain activation during the performance of behavioural inhibition to general and food-related stimuli in adults with bulimia nervosa.

METHODS

Women with bulimia and healthy control women underwent event-related fMRI while performing a general and a food-specific no-go task.

RESULTS

We included 28 women with bulimia nervosa and 29 healthy control women in our study. On a neuronal level, we observed significant group differences in response to general no-go stimuli in women with bulimia nervosa with high symptom severity; compared with healthy controls, the patients showed reduced activation in the right sensorimotor area (postcentral gyrus, precentral gyrus) and right dorsal striatum (caudate nucleus, putamen).

LIMITATIONS

The present results are limited to adult women with bulimia nervosa. Furthermore, it remains unclear whether impaired behavioural inhibition in patients with this disorder are a cause or consequence of chronic illness.

CONCLUSION

Our findings suggest that diminished frontostriatal brain activation in patients with bulimia nervosa contribute to the severity of binge eating symptoms. Gaining further insight into the neural mechanisms of behavioural inhibition problems in individuals with this disorder may inform brain-directed treatment approaches and the development of response inhibition training approaches to improve inhibitory control in patients with bulimia nervosa. The present study does not support greater behavioural and neural impairments to food-specific behavioural inhibition in these patients.

Cued to Act on Impulse: More Impulsive Choice and Risky Decision Making by Women Susceptible to Overeating after Exposure to Food Stimuli

There is increasing evidence that individual differences in tendency to overeat relate to impulsivity, possibly by increasing reactivity to food-related cues in the environment. This study tested whether acute exposure to food cues enhanced impulsive and risky responses in women classified on tendency to overeat, indexed by scores on the three factor eating questionnaire disinhibition (TFEQ-D), restraint (TFEQ-R) and hunger scales. Ninety six healthy women completed two measures of impulsive responding (delayed discounting, DDT and a Go No-Go, GNG, task) and a measure of risky decision making (the balloon analogue risk task, BART) as well as questionnaire measures of impulsive behaviour either after looking at a series of pictures of food or visually matched controls. Impulsivity (DDT) and risk-taking (BART) were both positively associated with TFEQ-D scores, but in both cases this effect was exacerbated by prior exposure to food cues. No effects of restraint were found. TFEQ-D scores were also related to more commission errors on the GNG, while restrained women were slower on the GNG, but neither effect was modified by cue exposure. Overall these data suggest that exposure to food cues act to enhance general impulsive responding in women at risk of overeating and tentatively suggest an important interaction between tendency for impulsive decision making and food cues that may help explain a key underlying risk factor for overeating.

Examining impulsivity as a moderator of the relationship between body shame and bulimic symptoms in Black and White young women

Impulsivity has been linked to bulimic symptomatology in a number of studies; however, few have examined this relationship among Black women. We investigated the correlations between impulsivity and bulimic symptoms, and tested impulsivity as a moderator of the body shame/bulimic symptoms relationship among a sample of female undergraduates (N=276; 97 Blacks, 179 Whites). These participants provided data on body shame, impulsivity, and bulimic symptoms (EDE-Q binge eating frequency, BULIT-R, EDI-Bulimia). Among Blacks, impulsivity was significantly positively associated with all bulimic symptoms measures; among Whites, impulsivity was only positively correlated with binge eating frequency. Furthermore, among Blacks, the combination of high body shame and high impulsivity was associated with the highest levels of bulimic symptoms; these findings were not observed among Whites. This study highlights the importance of impulsivity and body shame in identifying bulimic symptomatology among Black women.

Neural correlates of high-risk behavior tendencies and impulsivity in an emotional Go/NoGo fMRI task

Improved neuroscientific understanding of high-risk behaviors such as alcohol binging, drug use, and unsafe sex will lead to therapeutic advances for high-risk groups. High-risk behavior often occurs in an emotionally-charged context, and behavioral inhibition and emotion regulation play important roles in risk-related decision making. High impulsivity is an important potential contributor to high-risk behavior tendencies. We explored the relationships between high-risk behavior tendencies, impulsivity, and fMRI brain activations in an emotional Go/NoGo task. This task presented emotional distractor pictures (aversive vs. neutral) simultaneously with Go/NoGo stimuli (square vs. circle) that required a button press or withholding of the press, respectively. Participants' risk behavior tendencies were assessed with the Cognitive Appraisal of Risky Events (CARE) scale. The Barratt Impulsivity Scale 11 (BIS) was used to assess participant impulsivity. Individuals with higher CARE risk scores exhibited reduced activation related to response inhibition (NoGo-Go) in right orbital frontal cortex (OFC) and ventromedial prefrontal cortex. These regions did not show a significant relationship with impulsivity scores. Conversely, more impulsive individuals showed reduced emotion-related activity (aversive-neutral distractors) in dorsomedial prefrontal cortex, perigenual anterior cingulate cortex, and right posterior OFC. There were distinct neural correlates of high-risk behavior tendency and impulsivity in terms of brain activity in the emotional Go/NoGo task. This dissociation supports the conception of high-risk behavior tendency as a distinct construct from that of impulsivity. Our results suggest that treatment for high-risk behavior may be more effective with a nuanced approach that does not conflate high impulsivity necessarily with high-risk behavior tendencies.

Psychometric properties of the Barratt Impulsiveness Scale in patients with gambling disorders, hypersexuality, and methamphetamine dependence

Although the Barratt Impulsiveness Scale (BIS; Patton, Stanford, & Barratt, 1995) is a widely-used self-report measure of impulsivity, there have been numerous questions about the invariance of the factor structure across clinical populations (Haden & Shiva, 2008, 2009; Ireland & Archer, 2008). The goal of this article is to examine the factor structure of the BIS among a sample consisting of three populations exhibiting addictive behaviors and impulsivity: pathological gamblers, hypersexual patients, and individuals seeking treatment for methamphetamine dependence to determine if modification to the existing factors might improve the psychometric properties of the BIS. The current study found that the factor structure of the BIS does not replicate in this sample and instead produces a 12-item three-factor solution consisting of motor-impulsiveness (5 items), non-planning impulsiveness (3 items), and immediacy impulsiveness (4 items). The clinical utility of the BIS in this population is questionable. The authors suggest future studies to investigate comparisons with this modified version of the BIS and other impulsivity scales such as the UPPS-P Impulsive Behavior Scale in clinical populations when assessing disposition toward rash action.

Impulsiveness in patients with bulimia nervosa: electrophysiological evidence of reduced inhibitory control

OBJECTIVES

Bulimia nervosa (BN) is associated with a deficit of self-regulatory control and impulsivity. The present study aimed to clarify whether an impaired inhibitory control due to hyperarousal underlies impulsivity in BN subjects.

METHODS

Event-related potentials (ERPs) were recorded in 17 female patients with BN and 17 healthy controls during a three-tone oddball task. ERP components related to inhibition of irrelevant distractor stimuli, as well as effortful processing, were analyzed. Standardized low-resolution electromagnetic tomography (sLORETA) was used to assess ERP source activity.

RESULTS

Compared to healthy controls, BN patients showed reduced amplitude and shorter latency of the N200 (N2), increased amplitude and shorter latency of the target slow wave (SW), and higher amplitude of the P300 for distractor stimuli (P3a) and for targets (P3b). sLORETA showed the following: (1) higher activity of the P3a generators in the left parietal cortex, bilateral precuneus and right frontal and anterior cingulate for distractor stimuli and (2) lower activity of the SW generators in the left medial frontal gyrus, bilateral superior frontal, anterior cingulate and cuneus for target stimuli. The reduction of the N2 latency was associated with the Barratt scores for impulsiveness.

CONCLUSIONS

The observed electrophysiological abnormalities suggest a condition of hyperarousal, with impaired suppression of irrelevant stimuli due to abnormal cortical activation and reduced signal-to-noise ratio. Our findings point to functional abnormalities within a neural system that subserves attention and self-regulatory control, which may contribute to impulsive behaviors in BN.

Difficulties in emotion regulation across the spectrum of eating disorders

Theoretical models consider difficulties in emotion regulation (ER) as central trans-diagnostic phenomena across the spectrum of eating disorders (ED). However, there is a lack of studies directly comparing ED subtypes regarding ER problems. Furthermore, patients with anorexia nervosa-restricting type (AN-R) and patients with AN-binge/purge type (AN-BP) have usually been merged into one overall AN group in previous research on ER. In order to overcome these limitations of previous studies, the present study investigated specific ER difficulties in 120 patients with different ED subtypes, including AN-R, AN-BP, bulimia nervosa (BN), and binge-eating disorder (BED). As compared to 60 healthy normal-weight controls (NWC) and 29 healthy over-weight controls (OWC), all ED subtypes reported greater difficulties in ER. ED subtypes did not differ regarding most domains of ER except BED showing less severe ER difficulties in some domains. In addition, AN-BP but not BN reported greater impulse control difficulties than AN-R and BED. The findings underscore the relevance of ER difficulties in ED and support the trans-diagnostic view of ER difficulties being present across the whole spectrum of ED. In addition, the present results suggest that certain domains of ER may be linked more closely to certain ED subtypes than to others.

Personality Assessment Inventory profiles of university students with eating disorders

BACKGROUND

Eating disorders are complex disorders that involve medical and psychological symptoms. Understanding the psychological factors associated with different eating disorders is important for assessment, diagnosis, and treatment.

METHODS

This study sought to determine on which of the 22 Personality Assessment Inventory (PAI) scales patients with anorexia nervosa, bulimia nervosa, and eating disorder not otherwise specified (EDNOS) differed, and whether the PAI can be used to classify eating disorder subtypes. Because we were interested in both whether the PAI could be used to differentiate eating disorder subtypes from each other, as well as from other disorders, we also included a group of patients with major depression.

RESULTS

The three eating disorder groups did differ significantly from each other, and from the patients with depression, on a number of the PAI scales. Only two PAI scales (Anxiety and Depression), however, exceeded a T-score of 70 for the patients with anorexia nervosa, no scales exceeded a T-score of 70 for the patients with bulimia nervosa or EDNOS, and only two exceeded a T-score of 70 for the patients with depression (Depression and Suicide). A discriminant function analysis revealed an overall correct classification between the groups of 81.6%.

CONCLUSIONS

The PAI helps to understand the psychological factors associated with eating disorders and can be used to assist with assessment. Continued investigation using the PAI in an eating disordered population is supported.

Inhibitory control in bulimic-type eating disorders: a systematic review and meta-analysis

The aim of this meta-analysis was to summarise data from neuropsychological studies on inhibitory control to general and disease-salient (i.e., food/eating, body/shape) stimuli in bulimic-type eating disorders (EDs). A systematic literature search was conducted to identify eligible experimental studies. The outcome measures studied included the performance on established inhibitory control tasks in bulimic-type EDs. Effect sizes (Hedges' g) were pooled using random-effects models. For inhibitory control to general stimuli, 24 studies were included with a total of 563 bulimic-type ED patients: 439 had bulimia nervosa (BN), 42 had anorexia nervosa of the binge/purge subtype (AN-b), and 82 had binge eating disorder (BED). With respect to inhibitory control to disease-salient stimuli, 12 studies were included, representing a total of 218 BN patients. A meta-analysis of these studies showed decreased inhibitory control to general stimuli in bulimic-type EDs (g = −0.32). Subgroup analysis revealed impairments with a large effect in the AN-b group (g = −0.91), impairments with a small effect in the BN group (g = −0.26), and a non-significant effect in the BED group (g = −0.16). Greater impairments in inhibitory control were observed in BN patients when confronted with disease-salient stimuli (food/eating: g = −0.67; body/shape: g = −0.61). In conclusion, bulimic-type EDs showed impairments in inhibitory control to general stimuli with a small effect size. There was a significantly larger impairment in inhibitory control to disease salient stimuli observed in BN patients, constituting a medium effect size.

Impulsivity and substance-related attentional bias: a meta-analytic review

BACKGROUND

Previous research demonstrates the role of attentional bias in addictive behaviors. Impulsivity is thought to affect the strength of attentional biases, and thus, attentional biases might be one mechanism by which impulsivity affects addictive behaviors. However, whether or not impulsivity is related to attentional biases across different conceptualizations of impulsivity and attentional biases has yet to be examined as an initial test of such causal models.

METHODS

The authors completed a meta-analysis of 13 published research studies examining the relationship between substance-related attentional bias and different conceptualizations of impulsivity.

RESULTS

There was a small and significant effect size between impulsivity and substance-related attentional bias (r=0.20), which was moderated by impulsivity measurement type (Qb=5.91, df=1, p<0.05): there was a stronger relationship between behavioral impulsivity and substance-related attentional bias (r=0.22) than trait impulsivity and substance-related attentional bias (r=0.10). Different components of behavioral impulsivity and trait impulsivity did not affect the relationship.

CONCLUSIONS

This study is the first systematic and empirical demonstration of the relationship between substance-related attentional bias and impulsivity and suggests viability of future examinations of casual models relating these constructs. Since trait and behavioral conceptualizations differentially relate to substance-related attentional bias, the current review further supports research suggesting how disaggregation of multidimensional constructs can lead to more robust relationships.

Understanding the relationships between body esteem, risk for anorexia nervosa, and domain-dependent decision-making impulsivity in a college sample

Impulsivity has been suggested to interact with low body esteem to elevate risk for anorexia nervosa. Discounting tasks are unique tools for examining impulsivity. Female college students (N=139) at varying levels of body esteem and risk for anorexia nervosa responded to discounting scenarios depicting opportunities to lose/gain weight and to worsen/improve complexion. Multiple regression analyses were used to examine the relationships between impulsivity and risk for anorexia nervosa and body esteem in four disorder-relevant decision-making contexts. Results indicated that lower decision-making impulsivity predicted lower body esteem levels when the outcome of the task was framed as an opportunity to lose weight. It is suggested that greater self-control regarding weight-loss in women with low body esteem may be problematic, placing them at higher risk for eating- and weight-related problems. Results reiterate the need for continued attention to fostering healthy body esteem and weight-control patterns in women on college campuses.

The neuropsychological profile of children at high risk of developing an eating disorder

BACKGROUND

There is a large body of evidence indicating that eating disorders (EDs) are characterized by particular neuropsychological profiles. We aimed to further explore whether impairments in neuropsychological functioning previously found in ED groups are present prior to onset, or are secondary to the disorder. Method This is the first study to explore neuropsychological functioning in children born to a mother with a lifetime ED, who are therefore at high risk of developing an ED, in a large cohort sample. We investigated intelligence and attention at age 8 years (n = 6201) and working memory (WM) and inhibition at age 10 years (6192) in children who are at high risk of developing an ED, compared to children who are not.

RESULTS

The children of women with lifetime anorexia nervosa (AN) showed high full-scale and performance IQ, increased WM capacity, better visuo-spatial functioning, and decreased attentional control. The children of women with lifetime bulimia nervosa (BN) showed comparatively poor visuo-spatial functioning.

CONCLUSIONS

Our findings suggest that high intelligence, increased WM capacity and impaired attentional control might be intermediate phenotypes on the pathway between genetic vulnerability and the development of an ED.

The role of impulsivity, inattention and comorbid ADHD in patients with bulimia nervosa

Introduction

Little is known about the contribution of impulsivity, inattention and comorbid attention deficit/hyperactivity disorder (ADHD) in the development and maintenance of bulimia nervosa (BN). In particular, their specific contribution to disordered eating symptoms and whether they have additive effects to the general psychopathological burden remains unclear.

Methods

Fifty-seven female patients seeking treatment for BN and 40 healthy controls completed diagnostic questionnaires and interviews that investigated: a) ADHD, b) impulsivity, c) eating disorders and d) general psychopathology. Attentional processes and impulsivity were assessed by a comprehensive computer-based neuropsychological battery.

Results

Twenty-one percent of patients with BN met the clinical cut-off for previous childhood ADHD compared to 2.5% of healthy controls. Adult ADHD according to DSM IV was also more prevalent in patients with BN, with an odds ratio of 4.2. Patients with BN and previous childhood ADHD were more impulsive and inattentive than patients with BN alone. These patients also displayed more severely disordered eating patterns and more general psychopathological symptoms compared with those without ADHD. Severity of eating disorder symptoms was better explained by inattentiveness than by either impulsivity or hyperactivity.

Discussion

Our data suggest an elevated rate of former childhood and current ADHD-symptoms in treatment-seeking patients with BN. Stronger impulsivity and inattention associated with more severe neuropsychological deficits and eating disorder symptoms indicate an additive risk that is clinically relevant for these patients. Thus, clinicians should identify comorbid patients who might profit from additional ADHD-specific treatments.

Divergent neural substrates of inhibitory control in binge eating disorder relative to other manifestations of obesity

OBJECTIVE

An important endeavor involves increasing our understanding of biobehavioral processes underlying different types of obesity. The current study investigated the neural correlates of cognitive control (involving conflict monitoring and response inhibition) in obese individuals with binge eating disorder (BED) as compared to BMI-matched non-BED obese (OB) individuals and lean comparison (LC) participants. Alterations in cognitive control may contribute to differences in behavioral control over eating behaviors in BED and obesity.

DESIGN AND METHODS

Participants underwent functional magnetic resonance imaging while completing the Stroop color-word interference task.

RESULTS AND CONCLUSIONS

Relative to the OB and LC groups, activity in the BED group was differentiated by relative hypoactivity in brain areas involved in self-regulation and impulse control. Specifically, the BED group showed diminished activity in the ventromedial prefrontal cortex (vmPFC), inferior frontal gyrus (IFG), and insula during Stroop performance. In addition, dietary restraint scores were negatively correlated with right IFG and vmPFC activation in the BED group, but not in the OB or HC groups. Thus, BED individuals' diminished ability to recruit impulse-control-related brain regions appears associated with impaired dietary restraint. The observed differences in neural correlates of inhibitory processing in BED relative to OB and LC groups suggest distinct eurobiological contributions to binge eating as a subgroup of obese individuals.

Neuropsychology of eating disorders: 1995-2012

Eating disorders are considered psychiatric pathologies that are characterized by pathological worry related to body shape and weight. The lack of progress in treatment development, at least in part, reflects the fact that little is known about the pathophysiologic mechanisms that account for the development and persistence of eating disorders. The possibility that patients with eating disorders have a dysfunction of the central nervous system has been previously explored; several studies assessing the relationship between cognitive processing and certain eating behaviors have been conducted. These studies aim to achieve a better understanding of the pathophysiology of such diseases. The aim of this study was to review the current state of neuropsychological studies focused on eating disorders. This was done by means of a search process covering three relevant electronic databases, as well as an additional search on references included in the analyzed papers; we also mention other published reviews obtained by handsearching.

Plasticity of verbal fluency in older adults: a 90-minute telephone-based intervention

BACKGROUND

There is evidence for specific age-related deficits in tasks of verbal fluency.

OBJECTIVE

The aim of the present study was to evaluate training and transfer effects after 3 weeks of telephone-based verbal fluency training in old age.

METHODS

Participants were assigned to one of three training groups, an active control group, or a no-contact control group. Training consisted of 15 sessions of 6 min each over a period of 3 weeks. For the training tasks, different versions of the verbal fluency task were used, each targeting a specific underlying cognitive process (i.e., processing speed, shifting, or inhibition). To measure transfer effects, a neuropsychological test battery including digit symbol substitution, trail making, go/no-go, digit span, n-back, and a verbal learning and memory test was administered before and after training.

RESULTS

Our findings revealed training gains for initial letter fluency training and phonemic switching training, but not for excluded letter fluency training. Moreover, after initial letter fluency training and phonemic switching training, transfer to other verbal fluency tasks was found. In addition, phonemic switching training led to improvement in an untrained short-term memory task.

CONCLUSION

The findings demonstrate that a telephone-based cognitive intervention of overall 90 min significantly improved cognitive performance in healthy older adults above and beyond the improvements in the active control group. The findings provide the basis for cognitive interventions that could easily be integrated into everyday lifestyles and are still targeting specific cognitive functions.

Classical Stroop effect in bulimia nervosa

Bulimia nervosa (BN) is a distressing condition. Its pathogenesis is not fully understood. Neurocognitive functioning, and particularly inhibitory control, is a potential biomarker that may improve our understanding of BN. A few small-scale studies have used the classical Stroop Colour Word Test (SCWT) in BN with contradictory findings. We examined SCWT performance in a large sample of people with BN (N=72), eating disorder not otherwise specified--bulimic type (N=43) and healthy controls (N=50). The results found no difference between groups on Stroop interference effect. These findings question the utility of the classical SCWT as an assessment tool in examining executive functioning in BN.

A study of neurocognition in bulimia nervosa and eating disorder not otherwise specified-bulimia type

Neurocognition in bulimia nervosa (BN) is under-researched. This study investigated aspects of attention (d2-Letter Cancellation Task), inhibitory control (Stroop and go/no-go task), and decision making (Game of Dice Task) in 40 people with BN, 30 with eating disorder not otherwise specified-BN type (EDNOS-BN), and 65 healthy controls (HCs). The National Adult Reading Test (NART) and Depression Anxiety Stress Scale (DASS-21) were also administered. Analyses of covariance (covariates: age, NART, and DASS-21) showed that people with BN and EDNOS-BN performed as well as HCs on all tasks. Attention task performance was poorer in the EDNOS-BN than in the BN group.

An investigation of Goodman's addictive disorder criteria in eating disorders

The aim of this study was to examine how far Goodman's addictive disorder criteria were met by individuals with eating disorders according to subtypes. The study provided a cross-sectional comparison among three samples of eating disorders [restricting anorexia nervosa (R-AN), N = 68; purging anorexia nervosa (P-AN), N = 42; and bulimia nervosa (BN), N = 66], a sample of substance-related disorders (SRDs, N = 48) and a sample of matched controls (N = 201). Diagnosis of addictive disorder was made following Goodman's criteria. Addictive personality traits were assessed with the Addiction Potential Scale of the Minnesota Multiphasic Personality Inventory--2 and with the Zuckerman's Sensation Seeking Scale. Results showed that individuals with BN met Goodman's addictive disorder criteria in the same proportion as drug-addicted individuals (65% vs 60%, p = NS). They both showed higher rates than R-AN individuals (35%; R-AN versus BN: F = 11.9, p < 0.001 and R-AN versus SRD: F = 7.16, p < 0.01). Although BN and SRD showed higher rates of addictive disorders compared with P-AN, differences were not significant. Scores on the Sensation Seeking and on the Addictive Potential scales paralleled the distribution of addictive disorders, with individuals with BN and with P-AN showing higher levels than individuals with R-AN. Results showed that a subgroup of individuals with an eating disorder experiences their disorder as an addiction and may deserve specific therapeutic attention.

Frontocingular dysfunction in bulimia nervosa when confronted with disease-specific stimuli

OBJECTIVE

Bulimia nervosa (BN) is characterized by dysregulation of impulse control, in other words, uncontrolled eating. Functional neuroimaging studies have been sparse and have used variable methodologies.

METHOD

Thirteen medication-free female BN patients and 13 female healthy controls were investigated by functional magnetic resonance imaging using a disease-specific food paradigm. Stimuli were rated after the scanning procedure.

RESULTS

Bulimia nervosa patients showed increased fear ratings and a trend for increased disgust. Magnetic resonance imaging data of 10 BN patients could be analysed. Three BN patients had to be excluded from the analysis because of minimal blood oxygen level dependent signals. Compared with healthy controls, BN patients showed less activation of the anterior cingulate cortex, which extended into the lateral prefrontal cortex. Furthermore, the right temporal pole showed decreased reactivity.

DISCUSSION

This study substantiates a key role of lateral prefrontal dysfunction in BN, a brain region involved in impulse control. Furthermore, the anterior cingulate cortex, which plays a key role in emotion processing, is dysfunctional. A major limitation of this study is the small sample size.

Neurocognition in bulimic eating disorders: a systematic review

Van den Eynde F, Guillaume S, Broadbent H, Stahl D, Campbell IC, Schmidt U, Tchanturia K. Neurocognition in bulimic eating disorders: a systematic review.

OBJECTIVE

  The aim of this study was to review the literature on neurocognition comparing people with a bulimic eating disorder in the acute phase of the illness with healthy controls (HC).

METHOD

  The review follows the PRISMA (preferred reporting items for systematic reviews and meta-analysis) statement guidelines. Three databases (Medline, Web of Science, and Scopus) were searched combining the search terms 'bulimic disorder', 'bulimia nervosa (BN)', 'binge-eating disorder (BED)' with terms referring to cognitive domains (e.g. 'executive functions').

RESULTS

  Thirty-seven studies on people with BN and four on people with BED were selected for review. Overall, sample sizes were relatively small [bulimic disorders: median and range 22 (12-83); HC: 27 (13-172)]. The diversity in methodology precluded a meta-analytical approach. People with a bulimic disorder did not present with a clear neurocognitive profile. Inclusion of salient, disorder-related stimuli (e.g. body weight/shape words) in the neurocognitive paradigms tended to generate differences between people with a bulimic disorder and HC.

CONCLUSION

  Neurocognition in bulimic eating disorders is under researched, and the available evidence is inconclusive. This review outlines strategies for further research in this area.