Central coherence in eating disorders: a systematic review

Set shifting and central coherence as neurocognitive endophenotypes in eating disorders: a preliminary investigation in twins

OBJECTIVES

Weak central coherence and poor set shifting are risk markers for eating disorders that are present post recovery and in first degree relatives. The aim of this study was to examine these traits in twins with eating disorders.

METHODS

Neuropsychological tests were administered to 114 female twins (n = 53 met lifetime DSM-IV eating disorder criteria, n = 19 non-eating disorder cotwins and n = 42 controls). Within pair correlations for monozygotic (MZ) and dizygotic (DZ) twins were calculated and generalised estimating equations (GEE) compared probands, with non-eating disorder cotwins and controls.

RESULTS

The genetic basis was highest for the central coherence tasks (Rey-Osterrieth Complex Figure Task: MZ twins r = 0.44 [CI: 0.07-0.70, P = 0.01] and Group Embedded Figures Test: MZ twins r = 0.58 [CI: 0.26-0.79, P = 0.00]). Poor set shifting was related to obsessive compulsive symptoms in both individuals with eating disorders and their non-eating disorder cotwins (r = 0.2-0.5).

CONCLUSION

Set shifting abilities and central coherence appear to be endophenotypes associated with eating disorders.

Is attention to detail a similarly strong candidate endophenotype for anorexia nervosa and bulimia nervosa?

OBJECTIVES

To investigate whether attention to detail is a similarly strong candidate endophenotype of anorexia (AN) and bulimia nervosa (BN), and to explore the incidence and clinical correlates of attention to detail.

METHODS

A total of 266 women (including AN, BN, recovered AN, unaffected sisters of AN/BN & control women) undertook a thorough clinical assessment and were administered two neuropsychological measures of attention to detail (Group Embedded Figure Test; Rey-Osterrieth Complex Figure).

RESULTS

Superior attention to detail was found across all AN groups including recovered AN and unaffected AN sisters. Those with BN and their unaffected sisters showed a profile more consistent with poor global integration. The combined effect of superior attention to detail and poor global integration ("weak coherence") was present in 42.3% of active cases and corresponded with a more severe illness, elevated obsessive-compulsive symptoms, and a higher likelihood of comorbid clinical anxiety and self-harm.

CONCLUSIONS

Attention to detail is a stronger candidate endophenotype of AN compared to BN, where poor global integration may be more relevant. The unique contribution of both aspects of weak coherence (superior attention to detail/poor global integration) requires further exploration and understanding in both eating disorders. Integrating cognitive remediation of these traits into treatment for the subset of patients it is relevant for may improve outcome.

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.

Do restrictive and bingeing/purging subtypes of anorexia nervosa differ on central coherence and set shifting?

OBJECTIVE

Anorexia nervosa (AN) has been associated with weak central coherence (CC) and weak set shifting (SS). The main aim of this study was to examine possible differences between restrictive AN (AN-R) and bingeing/purging AN (AN-BP) on these features.

METHODS

A total of 31 patients with AN-R, 20 patients with AN-BP and 26 healthy controls (HC) completed five neuropsychological tests (Block Design, Object Assembly, an adapted task-switching paradigm, Wisconsin Card Sorting Test and Trail Making Test).

RESULTS

Using Block Design and Object Assembly, indicative for CC, AN-R patients performed significantly worse than AN-BP patients and HC, without any difference between AN-BP and HC. On SS measures, no group differences were observed.

DISCUSSION

The results suggest that cognitive profiles of AN-R and AN-BP patients differ significantly on CC and not on SS. Our current findings support the idea that the two subtypes of AN have a distinctive underlying nature and might need a different approach in cognitive remediation.

Evaluation of enhanced attention to local detail in anorexia nervosa using the embedded figures test; an FMRI study

The behavioural literature in anorexia nervosa and autism spectrum disorders has indicated an overlap in cognitive profiles. One such domain is the enhancement of local processing over global processing. While functional imaging studies of autism spectrum disorder have revealed differential neural patterns compared to controls in response to tests of local versus global processing, no studies have explored such effects in anorexia nervosa. This study uses functional magnetic resonance imaging in conjunction with the embedded figures test, to explore the neural correlates of this enhanced attention to detail in the largest anorexia nervosa cohort to date. On the embedded figures tests participants are required to indicate which of two complex figures contains a simple geometrical shape. The findings indicate that whilst healthy controls showed greater accuracy on the task than people with anorexia nervosa, different brain regions were recruited. Healthy controls showed greater activation in the precuneus whilst people with anorexia nervosa showed greater activation in the fusiform gyrus. This suggests that different cognitive strategies were used to perform the task, i.e. healthy controls demonstrated greater emphasis on visuospatial searching and people with anorexia nervosa employed a more object recognition-based approach. This is in accordance with previous findings in autism spectrum disorder using a similar methodology and has implications for therapies addressing the appropriate adjustment of cognitive strategies in anorexia nervosa.

Perception of affect in biological motion cues in anorexia nervosa

OBJECTIVE

Nonverbal motion cues (a clenched fist) convey essential information about the intentions of the actor. Individuals with anorexia nervosa (AN) have demonstrated impairment in deciphering intention from facial affective cues, but it is unknown whether such deficits extend to deciphering affect from body motion cues.

METHOD

We examined the capacities of adults with AN (n = 21) or those weight restored for ≥12 months (WR; n = 20) to perceive affect in biological motion cues relative to healthy controls (HC; n = 23).

RESULTS

Overall, individuals with AN evidenced greater deficit in discriminating affect from biological motion cues than WR or HC. Follow-up analyses showed that individuals with AN differed especially across two of the five conditions--deviating most from normative data when discriminating sadness and more consistently discriminating anger relative to WR or HC.

DISCUSSION

Implications of these findings are discussed in relation to some puzzling interpersonal features of AN.

An experimental exploration of social problem solving and its associated processes in anorexia nervosa

People with Anorexia Nervosa (AN) have well-documented socio-emotional and neurocognitive impairments. As yet, little is known about their ability to solve problems in social situations, although a link with cognitive avoidance has been suggested. This study explored social problem-solving (SPS), using an experimental task. Secondly, the role of cognitive avoidance in SPS was investigated. Individuals with AN (n=31) and healthy controls (HC; n=39) completed the Social Problem Resolution Task which consists of problem scenarios involving awkward everyday social situations. Participants were asked to generate both the optimal solution and their personal solution. Solutions were rated in terms of how socially sensitive and practically effective they were. AN patients produced relatively poorer personal solutions compared to optimal solutions than HC participants and had higher scores on a measure of cognitive avoidance than the HC group. In AN patients, cognitive avoidance was partially associated with poor SPS. These findings suggest that whilst people with AN have no difficulty in generating socially sensitive and effective solutions to problems, but may have difficulty applying this knowledge to themselves.

Interpersonal motives in anorexia nervosa: the fear of losing one's autonomy

OBJECTIVE

This study examined the widely held but insufficiently studied hypothesis of autonomy disturbances in anorexia nervosa.

METHOD

A total sample of 112 participants comprising patients with acute anorexia nervosa (AN), women recovered from anorexia nervosa (REC), clinical controls (CC), and healthy controls (HC) completed measures of dependency and intimacy strivings, as well as measures of frustrations of these same strivings.

RESULTS

In comparison to HC and CC, AN showed a stronger motivation to avoid dependency and lower strivings for intimacy. Compared with HC, but not with CC, AN also showed stronger frustrations of the same motives. Whereas REC did not differ from AN regarding avoidance of dependency, they reported lower frustration of dependency avoidance (i.e., less actual experiences of dependency). Finally, REC reported higher intimacy motivation as well as better satisfaction of intimacy motivation as compared with AN.

CONCLUSIONS

The present findings suggest that a pronounced motive of avoiding dependency may be a vulnerability factor for anorexia nervosa that is disorder-specific and trait-like. Frustrations of this motive seem to be associated with psychopathology.

A review of attention biases in women with eating disorders

There is robust evidence that women with eating disorders (EDs) display an attention bias (AB) for disorder-salient stimuli. Emerging data suggest that the presence of these biases may be due, in part, to neurological deficits, such as poor set shifting and weak central coherence. While some have argued that these biases function to predispose and/or act to maintain disordered eating behaviours, evidence supporting this view has rarely been examined. This report summarises and integrates the existing literature on AB in EDs and other related psychiatric disorders to better understand its potential role in the development and maintenance of an ED. The domains reviewed include experimental data using the dot-probe and modified Stroop task and neurobiological findings on AB in women with EDs as well as the role of AB in current theoretical models. We conclude by proposing an integrated model on the role of AB in EDs and discuss treatment approaches aimed at modifying these biases.

Emotional intelligence in anorexia nervosa: is anxiety a missing piece of the puzzle?

Problematic emotional processing has been implicated in the genesis and maintenance of anorexia nervosa (AN). This study built on existing research and explored performance-based emotional intelligence (EI) in people with AN. The Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT) was administered to 32 women diagnosed with AN and 32 female healthy controls (HC). Compared to HC women, the AN group demonstrated significantly lower total EI scores and poorer ability to understand how emotions can progress and change over time. Despite scores within the broadly average range compared to published EI norms, there was a general pattern of poorer performance in the AN sample. Self-reported anxiety symptoms were the strongest predictor of EI, over and above a diagnosis of AN. This study adds to the literature documenting the socioemotional phenotype of AN, suggesting this group of individuals may find it relatively difficult to carry out accurate reasoning about emotions, and to use emotions and emotional knowledge to enhance thought. Anxiety was highlighted as a putative variable partially explaining why people with AN demonstrated lower EI compared to controls. Implications for further research are discussed, including the need to explore the specificity of EI difficulties in AN using larger samples and additional control groups.

Central coherence in full recovery of anorexia nervosa

OBJECTIVE

This study examined central coherence as a possible endophenotype in a large sample of women recovered from anorexia nervosa (rec AN). Recovery was defined by considering physiological, behavioural and psychological variables.

METHOD

A total of 100 rec AN women and 100 healthy women completed the Rey Complex Figure Test, a measure for visual-spatial central coherence. The participants were matched 1:1 for age and educational level.

RESULTS

Compared with the healthy control group, the rec AN group showed better accuracy in the copy condition. There was a trend for a local strategy in the rec AN group compared with a global strategy in the healthy control group.

CONCLUSIONS

This sample of rec AN women showed no inefficiencies in global processing but a superior local processing after full recovery from AN.

Decision-making and planning in full recovery of anorexia nervosa

OBJECTIVE

Based on findings of persisting neuropsychological impairments in women recovered from anorexia nervosa (rec AN), this study examined decision-making and planning, for achieving a desired goal, as central executive functions in a large sample of rec AN. The definition of recovery included physiological, behavioral, and psychological variables.

METHOD

A total of 100 rec AN women were compared to 100 healthy women, 1:1 matched for age and educational level. Decision-making was assessed with the Iowa Gambling Task and planning with the Tower of London. Expert interviews and self-ratings were used for assessing the inclusion/exclusion criteria and control variables.

RESULTS

Compared to healthy controls, rec AN women were better in decision-making and worse in planning even after considering control variables.

DISCUSSION

This study does not support results from other studies showing that rec AN participants perform better in decision-making. Results from this study show that planning is impaired even after full recovery from AN.

Out-patient psychological therapies for adults with anorexia nervosa: randomised controlled trial

BACKGROUND

Very limited evidence is available on how to treat adults with anorexia nervosa and treatment outcomes are poor. Novel treatment approaches are urgently needed.

AIMS

To evaluate the efficacy and acceptability of a novel psychological therapy for anorexia nervosa (Maudsley Model of Anorexia Nervosa Treatment for Adults, MANTRA) compared with specialist supportive clinical management (SSCM) in a randomised controlled trial.

METHOD

Seventy-two adult out-patients with anorexia nervosa or eating disorder not otherwise specified were recruited from a specialist eating disorder service in the UK. Participants were randomly allocated to 20 once weekly sessions of MANTRA or SSCM and optional additional sessions depending on severity and clinical need (trial registration: ISRCTN62920529). The primary outcomes were body mass index, weight and global score on the Eating Disorders Examination at end of treatment (6 months) and follow-up (12 months). Secondary outcomes included: depression, anxiety and clinical impairment; neuropsychological outcomes; recovery rates; and additional service utilisation.

RESULTS

At baseline, patients randomised to MANTRA were significantly less likely to be in a partner relationship than those receiving SSCM (3/34 v. 10/36; P<0.05). Patients in both treatments improved significantly in terms of eating disorder and other outcomes, with no differences between groups. Strictly defined recovery rates were low. However, MANTRA patients were significantly more likely to require additional in-patient or day-care treatment than those receiving SSCM (7/34 v. 0/37; P = 0.004).

CONCLUSIONS

Adults with anorexia nervosa are a difficult to treat group. The imbalance between groups in partner relationships may explain differences in service utilisation favouring SSCM. This study confirms SSCM as a useful treatment for out-patients with anorexia nervosa. The novel treatment, MANTRA, designed for this patient group may need adaptations to fully exploit its potential.

Worry and Rumination in Anorexia Nervosa

Background: Difficulties with comprehending and managing emotions are core features of the pathology of anorexia nervosa (AN). Advancements in understanding aetiology and treatment have been made within other clinical domains by targeting worry and rumination. However, worry and rumination have been given minimal consideration in AN. Aims: This study is the largest to date of worry and rumination in AN. Method: Sixty-two outpatients with a diagnosis of AN took part. Measures of worry, rumination, core AN pathology and neuropsychological correlates were administered. Results: Findings suggest that worry and rumination are elevated in AN patients compared with both healthy controls and anxiety disorder comparison groups. Regression analyses indicated that worry and rumination were significant predictors of eating disorder symptomatology, over and above the effects of anxiety and depression. Worry and rumination were not associated with neuropsychological measures of set-shifting and focus on detail. Conclusions: The data suggest that worry and rumination are major concerns for this group and warrant further study.

What can cognitive neuroscience teach us about anorexia nervosa?

Anorexia nervosa (AN) is a complex illness and highly challenging to treat. One promising approach to significantly advance our understanding of the underlying pathophysiology of AN involves developing a cognitive neuroscience model of illness. Cognitive neuroscience uses probes such as neuropsychological tasks and neuroimaging techniques to identify the neural underpinnings of behavior. With this approach, advances have been made in identifying higher-order cognitive processes that likely mediate symptom expression in AN. Identification of related neuropathology is beginning. Such findings led to the development of complex neurobehavioral models that aim to explain the etiology and persistence of AN. Future research will use these advanced tools to test and refine hypotheses about the underlying mechanisms of AN.

Theory of mind and the brain in anorexia nervosa: relation to treatment outcome

OBJECTIVE

Converging evidence suggests deficits in theory-of-mind (ToM) processing in patients with anorexia nervosa (AN). The present study aimed at elucidating the neural mechanisms underlying ToM-deficits in AN.

METHOD

A total of 19 adolescent patients with AN and 21 age-matched controls were investigated using functional magnetic resonance imaging during performance of a ToM-task at two time points (in-patients: admission to hospital and discharge after weight recovery). Clinical outcomes in patients were determined 1 year after admission.

RESULTS

Irrespective of the time point, AN patients showed reduced activation in middle and anterior temporal cortex and in the medial prefrontal cortex. Hypoactivation in the medial prefrontal cortex at admission to hospital (T1) was correlated with clinical outcome at follow-up.

CONCLUSIONS

Hypoactivation in the brain network supporting theory of mind may be associated with a social-cognitive endophenotype reflecting impairments of social functioning in anorexia nervosa which is predictive for a poor outcome at 1-year follow-up.

Neuropsychological weaknesses in anorexia nervosa: set-shifting, central coherence, and decision making in currently ill and recovered women

OBJECTIVE

The purpose of this study is to examine set-shifting, central coherence, and decision making in women currently ill with anorexia nervosa (AN), women recovered from AN, and healthy control women. We aim to test whether these neuropsychological weaknesses persist after recovery, and explore relations between the impairments

RESULTS

Compared to control women, ill and recovered women showed poor set-shifting and decision making. There were strong correlations between set-shifting and central coherence in the ill and recovered women. Decision making did not correlate with the other measures.

DISCUSSION

The present findings suggest that impaired set-shifting and decision making are stable traits in women with AN. Because individual differences within these groups were large, a rigid thinking style is only present in a (sub)population of ill and recovered women. Decision-making performance is not related to a rigid thinking style, but further research in this area is warranted.

Altered implicit category learning in anorexia nervosa

OBJECTIVE

Recent research has identified specific cognitive deficits in patients with anorexia nervosa (AN), including impairment in executive functioning and attention. Another such cognitive process, implicit category learning has been less studied in AN. This study examined whether implicit category learning is impaired in AN.

METHOD

Twenty-one women diagnosed with AN and 19 control women (CW) were administered an implicit category learning task in which they were asked to categorize simple perceptual stimuli (Gabor patches) into one of two categories. Category membership was based on a linear integration (i.e., an implicit task) of two stimulus dimensions (orientation and spatial frequency of the stimulus).

RESULTS

AN individuals were less accurate on implicit category learning relative to age-matched CW. Model-based analyses indicated that, even when AN individuals used the appropriate (i.e., implicit) strategy they were still impaired relative to CW who also used the same strategy. In addition, task performance in AN patients was worse the higher they were in self-reported novelty seeking and the lower they were in sensitivity to punishment.

CONCLUSIONS

These results indicate that AN patients have implicit category learning deficits, and given this type of learning is thought to be mediated by striatal dopamine pathways, AN patients may have deficits in these neural systems. The finding of significant correlations with novelty seeking and sensitivity to punishment suggests that feedback sensitivity is related to implicit learning in AN.

Clinical and biological correlates of adolescent anorexia nervosa with impaired cognitive profile

Some neuropsychological studies of anorexia nervosa (AN) have yielded conflicting results, and it has been established that not all adult patients with AN are cognitively impaired. The objective of this study is to determine the percentage of adolescents with AN who present worse cognitive functioning according to neuropsychological criteria of cognitive impairment, and to study their clinical characteristics. Thirty-seven adolescents (11-18 years) with a diagnosis of AN in an acute state of the illness and with low body mass index (BMI) were compared with 41 healthy subjects of the same sex and similar age and intelligence using a comprehensive neuropsychological battery. Overall, AN patients took longer to copy Rey's Figure than the control group (p = 0.001). Thirty per cent of patients showed impaired neuropsychological functioning (defined as scoring two standard deviations lower than the average or lower than their intelligence level in two tasks) with worse performance on visuo-spatial tasks. This subgroup of patients presented lower BMI (p = 0.023) and higher trait anxiety (p = 0.028). The performance of adolescents in an acute state of AN was similar to that of the healthy control group, with the exception of lower time to completion in copying a complex figure. However, cognitive performance varied in these patients, being clearly impaired in one-third of the sample. The cognitive impairment subgroup showed lower BMI and higher anxiety. Longitudinal follow-up studies are necessary to assess the stability of this profile after longer treatment periods.

Social emotional functioning and cognitive styles in eating disorders

OBJECTIVES

Contemporary models of eating disorders (EDs) argue that both cognitive style (weak coherence and poor set shifting) and social emotional difficulties are involved in the maintenance of EDs. This study aimed to explore the factor structure of cognitive and social emotional functioning and to investigate whether a particular cognitive or social emotional profile was associated with a more severe and chronic form of illness.

DESIGN

A cross-sectional design was used to investigate cognitive and social emotional functioning in people with EDs compared to healthy controls (HCs) and those recovered from an ED.

METHODS

Two hundred twenty-five participants were assessed (100 with an ED, 35 recovered from an ED, and 90 HCs) using a battery of set shifting, coherence, and social emotional measures.

RESULTS

There were no significant correlations between the cognitive or social emotional variables. A principal components analysis (PCA) identified three components: a fragmented perseverative cognitive style, for which the ED group scored highly, a global flexible cognitive style, for which HCs scored highly, and a social emotional difficulties profile, for which those with EDs scored highly. Individuals in recovery from an ED did not differ from the acute group, suggesting this cognitive and social emotional profile may be a trait associated with EDs. ED participants scoring highest for the fragmented perseverative cognitive style and social emotional difficulties had a more severe and chronic form of illness.

CONCLUSIONS

The findings provide empirical support for Schmidt and Treasure's (2006) maintenance model of EDs and suggest both cognition and emotional functioning should be considered in treatment.

Clinical and biological correlates of adolescent anorexia nervosa with impaired cognitive profile

Some neuropsychological studies of anorexia nervosa (AN) have yielded conflicting results, and it has been established that not all adult patients with AN are cognitively impaired. The objective of this study is to determine the percentage of adolescents with AN who present worse cognitive functioning according to neuropsychological criteria of cognitive impairment, and to study their clinical characteristics. Thirty-seven adolescents (11-18 years) with a diagnosis of AN in an acute state of the illness and with low body mass index (BMI) were compared with 41 healthy subjects of the same sex and similar age and intelligence using a comprehensive neuropsychological battery. Overall, AN patients took longer to copy Rey's Figure than the control group (p = 0.001). Thirty per cent of patients showed impaired neuropsychological functioning (defined as scoring two standard deviations lower than the average or lower than their intelligence level in two tasks) with worse performance on visuo-spatial tasks. This subgroup of patients presented lower BMI (p = 0.023) and higher trait anxiety (p = 0.028). The performance of adolescents in an acute state of AN was similar to that of the healthy control group, with the exception of lower time to completion in copying a complex figure. However, cognitive performance varied in these patients, being clearly impaired in one-third of the sample. The cognitive impairment subgroup showed lower BMI and higher anxiety. Longitudinal follow-up studies are necessary to assess the stability of this profile after longer treatment periods.

Assessment of cognitive flexibility in anorexia nervosa--self-report or experimental measure? A brief report

This study investigated the correspondence between self-report and experimental measures of cognitive flexibility in individuals with anorexia nervosa (AN) and healthy controls (HCs). Ninety-four participants (45 individuals with AN and 49 HCs) completed the self-report Cognitive Flexibility Scale (CFS) and an experimental task, the Brixton Spatial Anticipation Test. The AN group performed poorly on both measures of cognitive flexibility compared with HCs. There was no significant correlation between the CFS scores and the errors on the Brixton Test for both groups. The findings suggest there is poor correspondence between the self-report measure of cognitive flexibility and performance on the flexibility test. These two assessment tools therefore cannot be used interchangeably to assess cognitive flexibility. Flexibility is an important clinical characteristic in AN. The results suggest that self-report and behavioral measures can be complementary, but cannot be used as an alternative to one another.

Development and validation of the Detail and Flexibility Questionnaire (DFlex) in eating disorders

Whilst neuropsychological testing provides the most accurate profile of cognitive functioning, the time consuming nature of individual assessment deems it impossible for many research and clinical settings. This paper presents the development and validation of the Detail and Flexibility Questionnaire (DFlex), a 24-item self-report scale measuring two aspects of neurocognitive functioning; cognitive rigidity (difficulty with set-shifting/flexibility) and attention to detail (weak coherence). Exploratory factor analysis extracted two subscales, further confirmed and refined by item response analysis. Both subscales showed high internal reliability, construct validity (as compared to relevant subscales of the Autistic-Spectrum Quotient) and strong discriminant validity with large effect sizes found between both lifetime eating disorder and healthy control groups, and between current and recovered anorexia nervosa. We suggest using the cognitive rigidity and attention to detail subscales independently to give a rough approximation of these two aspects of cognitive style as they manifest in the context of everyday life.

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.

Cognitive flexibility and clinical severity in eating disorders

OBJECTIVES

The aim of this study was to explore cognitive flexibility in a large dataset of people with Eating Disorders and Healthy Controls (HC) and to see how patient characteristics (body mass index [BMI] and length of illness) are related to this thinking style.

METHODS

A dataset was constructed from our previous studies using a conceptual shift test--the Brixton Spatial Anticipation Test. 601 participants were included, 215 patients with Anorexia Nervosa (AN) (96 inpatients; 119 outpatients), 69 patients with Bulimia Nervosa (BN), 29 Eating Disorder Not Otherwise Specified (EDNOS), 72 in long-term recovery from AN (Rec AN) and a comparison group of 216 HC.

RESULTS

The AN and EDNOS groups had significantly more errors than the other groups on the Brixton Test. In comparison to the HC group, the effect size decrement was large for AN patients receiving inpatient treatment and moderate for AN outpatients.

CONCLUSIONS

These findings confirm that patients with AN have poor cognitive flexibility. Severity of illness measured by length of illness does not fully explain the lack of flexibility and supports the trait nature of inflexibility in people with AN.

The Use of Motivational Interviewing in Anorexia Nervosa

Anorexia nervosa (AN) is often highly valued by the individual. This can result in the individual having ambiguous and ambivalent feelings towards change. This ambiguity and ambivalence poses a major hurdle within the treatment process. The use of motivational interviewing (MI) during the initial phase of treatment to subtly guide the individual towards committing to change is increasing. Working within the particular constraints that govern the treatment of AN, such as impaired cognitive function, age of the patient, and the natural (biological) and social (Mental Health Act) laws that govern the need to eat, it is possible to adjust particular assumptions of the MI model (e.g. patients autonomy) to enable treatment and care to be provided in the MI spirit (e.g. supportive, affirming and empathic).

Group cognitive remediation therapy for adolescents with anorexia nervosa

Cognitive remediation therapy (CRT) for anorexia nervosa (AN) is a relatively new intervention and targets neuropsychological deficits, such as set shifting difficulties, weak central coherence and visuospatial deficits. To date there are no published descriptions of CRT for adolescents with AN. CRT has been traditionally delivered on an individual basis but other modalities are currently being explored. This paper describes the process of a 10-session course of group-based CRT for adolescents with AN. The nine participants, aged 13-19, were being treated on an inpatient service. Group-based CRT was well received by the participants, who reported it to be fun and useful. Clinical impressions suggest that this approach is a potentially useful addition to the treatment of this challenging population.

Therapists' experiences of cognitive remediation therapy for anorexia nervosa: implications for working with adolescents

Cognitive Remediation Therapy (CRT) is a novel intervention developed for adults with anorexia nervosa (AN), which aims to improve "cognitive flexibility" and "holistic processing" thinking styles (Tchanturia et al., 2008; Tchanturia & Hambrook, 2009). The present study uses a qualitative approach to examine therapists' accounts of their work with inpatients suffering with AN. The objective of this study is to gain a broader understanding of how CRT has been implemented and utilized in daily life by this patient group. Therapists' letters were positive and motivational; acknowledging patients for their achievements while outlining some of the difficulties and emotions that patients experienced. Findings highlight that the majority of patients' difficulties related to their metacognitive ability and in transferring the skills to real life. Themes also concerned the processes and stages of CRT, where patients gradually drew skills from the intervention prior to making changes in their own lives. The implications of this approach for working with adolescents with eating disorders are explored. It is hoped that this study will help understanding of how CRT can be used as a treatment for AN; and how it could be developed for future work with young people.

Is anorexia nervosa a version of autism spectrum disorders?

OBJECTIVES

Similarities have been noted between cognitive profiles of anorexia nervosa (AN) and autism spectrum disorders (ASD). However, there are no direct comparison studies. This study aimed to compare the cognitive profile of AN against published ASD data on tasks measuring empathy, executive function and central coherence.

METHODS

Currently ill AN outpatients (n = 40) were statistically compared against published ASD scores on Reading the Mind in the Eyes, Voice and Films tasks (assessing empathy), Wisconsin Card Sorting Task (WCST) (assessing executive function) and Embedded Figures Task (EFT) (assessing detail focus aspect of central coherence).

RESULTS

Cognitive profiles of the groups were statistically similar, except for differences in the relative patterns of empathy scores.

CONCLUSIONS

The cognitive profile in current AN resembles that of ASD with important clinical implications. Replication studies with planned comparisons, examination of the state-or trait-nature of AN profile and clarification of factors underpinning similarities are required in order to broaden understanding of both disorders.

Estimated intelligence quotient in anorexia nervosa: a systematic review and meta-analysis of the literature

BACKGROUND

It has been hypothesised that people with anorexia nervosa have a higher intelligence quotient (IQ) level than the general population. The purpose of this review was to systematically appraise the research into reported IQ levels in people with anorexia nervosa.

METHODS

A search using the terms intelligence quotient, IQ, intelligence, cognition, eating disorders and anorexia was conducted in electronic databases only.

RESULTS

In all, 30 peer-reviewed studies written in English that used well established measures of intelligence quotient (the National Adult Reading Test and Wechsler Intelligence Scales) were identified. This review established that people with anorexia nervosa score 10.8 units and 5.9 units above the average intelligence quotient of the normative population on the National Adult Reading Test and Wechsler Intelligence Scales, respectively. An association was found between Body Mass Index and intelligence quotient, as measured by the National Adult Reading Test.

CONCLUSIONS

More studies including other eating disorder categories and recovered people are needed to explore important questions regarding the role of the intelligence quotient in treatment response.

Cognitive remediation therapy (CRT) for anorexia in group format: a pilot study

Cognitive Remediation Therapy (CRT) was designed to address the inflexible and detail focused thinking styles frequently reported in individuals with Anorexia Nervosa (AN). This paper reports the development and acceptability of a pilot of CRT for AN in group format. Four group sessions were designed and piloted with 30 patients in an eating disorder service. The voluntary drop out rate was 20%. Outcome measures targeting patients' self-reported cognitive flexibility, self esteem and motivation to change were completed in the first and last sessions. Statistically significant gains were found in self reported ability to change (p=0.03). Both patients and group facilitators found the group acceptable, useful and a positive experience.

Facial affect recognition in anorexia nervosa: is obsessionality a missing piece of the puzzle?

OBJECTIVE

Socio-emotional difficulties are thought to be important maintaining factors of eating disorders. Several studies point to deficits in facial affect recognition in anorexia nervosa (AN). However, the majority of these studies fail to control for comorbidity and its effect on emotional processing. This study aims to explore how patients with AN recognize happiness and sadness in human faces, controlling for different comorbidities, namely anxiety, depression, and obsessive-compulsive symptoms.

METHODS

Thirty patients with AN, and 40 healthy participants completed a facial emotion recognition task. This task measured discrimination accuracy, response bias and response time towards sad and happy faces presented at different durations (500 ms, 2000 ms). The associations between facial affect recognition and clinical symptoms and intelligence quotient were explored.

RESULTS

Regression analysis showed that discrimination accuracy of sad faces presented for 500 ms was significantly associated with AN diagnosis, body mass index, and Obsessive-compulsive symptoms. However, the level of Obsessive-compulsive symptoms was the strongest predictor of a poor discrimination of briefly presented sad faces.

CONCLUSIONS

Our results support previous studies that report emotional processing deficits in AN with obsessionality playing a pivotal role in this deficit.

Set-shifting abilities, central coherence, and handedness in anorexia nervosa patients, their unaffected siblings and healthy controls: exploring putative endophenotypes

OBJECTIVE

There is consistent evidence that anorexia nervosa (AN) is associated with an impairment of set-shifting abilities and central coherence. No study to date investigated handedness in AN. Our aim was to study set-shifting abilities, central coherence, and handedness in subjects with lifetime AN, in a sample of unaffected sisters and in healthy controls, in order to explore their suitability as endophenotypes of AN.

METHODS

The Edinburgh Handedness Inventory and several neuropsychological tasks (Wisconsin Card Sorting Test, Trail Making Test, Rey-Osterrieth Complex Figure Test, Overlapping Figures Test, Object Assembly and Block Design) were administered to 153 subjects with lifetime AN, 28 unaffected sisters and 120 healthy controls.

RESULTS

AN subjects and their healthy sisters showed poorer performances on most tasks investigating set-shifting and central coherence. In addition, we did not find any differences between long-term recovered subjects, weight-restored AN patients and those in an acute phase of their illness. AN subjects were significantly more likely to be left-handed than healthy controls (OR=2.8, 95% C.I. 1.1-7.2).

CONCLUSIONS

Set-shifting and central coherence seem to be promising cognitive endophenotypes that might help in the understanding of the pathogenetic processes involved in AN. Further studies on larger samples are needed to explore the generalizability and implications of our findings concerning handedness.

Anorexia nervosa: towards an integrative neuroscience model

We reviewed the evidence for emotion-related disturbances in anorexia nervosa (AN) from behavioural, cognitive, biological and genetic domains of study. These domains were brought together within the framework of an integrative neuroscience model that emphasizes the role of emotion and feeling and their regulation, in brain organization. PsychInfo and Medline searches were performed to identify published peer-reviewed papers on AN within each domain. This review revealed evidence for 'Emotion', 'Thinking and Feeling' and 'Self-regulation' disturbances in AN that span non-conscious to conscious processes. An integrative neuroscience framework was then applied to develop a model of AN, from which hypotheses for empirical investigation are generated. We propose that AN reflects a core disturbance in emotion at the earliest time stage of information processing with subsequent effects on the later stages of thinking, feeling and self-regulation.

Eating disorders

This Seminar adds to the previous Lancet Seminar about eating disorders, published in 2003, with an emphasis on the biological contributions to illness onset and maintenance. The diagnostic criteria are in the process of review, and the probable four new categories are: anorexia nervosa, bulimia nervosa, binge eating disorder, and eating disorder not otherwise specified. These categories will also be broader than they were previously, which will affect the population prevalence; the present lifetime prevalence of all eating disorders is about 5%. Eating disorders can be associated with profound and protracted physical and psychosocial morbidity. The causal factors underpinning eating disorders have been clarified by understanding about the central control of appetite. Cultural, social, and interpersonal elements can trigger onset, and changes in neural networks can sustain the illness. Overall, apart from studies reporting pharmacological treatments for binge eating disorder, advances in treatment for adults have been scarce, other than interest in new forms of treatment delivery.

Cognitive remediation therapy for eating disorders: development, refinement and future directions

In this chapter, we aim to address some basic conceptual and practical questions about cognitive remediation therapy (CRT) for eating disorders. We begin by providing an overall historical, conceptual, and theoretical framework for CRT. Next, we discuss the specific indications for how and why CRT might be useful for eating disorders based on existing neuropsychological research evidence. We also provide an overview of the types of tasks and stimuli used in CRT and a general protocol for a manualized version of CRT. In addition, modifications of the adult CRT manual for use with adolescents as well as preliminary acceptability of the approach with this younger age group are described. We also propose various ways to integrate CRT in a variety of inpatient and outpatient programmes. Finally, a discussion of potential future directions in research using the tools of neurocognitive assessment, imaging and treatment research is provided.

Emotional theory of mind and emotional awareness in recovered anorexia nervosa patients

OBJECTIVES

To examine whether an impaired ability to infer emotion in people with autism spectrum disorder (ASD) and difficulty with emotional theory of mind (eToM) are limited to the ill state or if this condition is a stable deficit that persists with recovery in adults with anorexia nervosa (AN). This is in keeping with observations of similarities between the disorders.

METHODS

Twenty-four participants fully recovered from AN were compared against a sample of currently ill AN patients (n = 40) and healthy controls (HCs) (n = 47) on forced-choice tasks assessing emotion recognition, basic or advanced eToM in other people, using sensory stimuli and on a written task measuring eToM ability for the self as well as for others.

RESULTS

Recovered participants performed well on eToM tasks and were significantly better than currently ill patients at inferring emotions in the self and in others. However, participants recovered from AN had some slight impairment in emotion recognition relative to HCs, particularly when recognizing positive emotions.

CONCLUSIONS

These findings indicate almost complete normalization of emotion recognition ability as well as the restoration of eToM in recovered patients, despite the observation of difficulties in both domains in currently ill patients. Findings suggest that similarities between AN and ASD in poor eToM are restricted to the currently ill AN state and such difficulties in AN may be a factor of starvation.

Risk factors for full- and partial-syndrome early adolescent eating disorders: a population-based pregnancy cohort study

OBJECTIVE

To identify prospective predictors of eating disorders in a population-based sample of 14-year-old boys and girls, using previously collected antenatal, biomedical, familial, demographic, and psychosocial data.

METHOD

Participants (N = 1,597) were drawn from the Western Australian Pregnancy Cohort (Raine) Study. Data were collected during pregnancy, at birth, and when children were aged 1, 2, 5, 8, 10, and 14 years. An adapted version of the Eating Disorder Examination Questionnaire was used to assess eating disorder symptoms at age 14 years. Logistic regression was used to identify prospective predictors of eating disorder caseness, relative to general control and psychiatric control groups.

RESULTS

At age 14 years, 6% of the sample met full or partial criteria for a DSM-IV eating disorder. Being female and being perceived as overweight by one's parent were the strongest predictors of eating disorder caseness in the final multivariate models, relative to both control groups. Maternal body mass index, social problems, low social-related self-efficacy, and neurocognitive difficulties were also predictive of eating disorder caseness relative to the general control group only.

CONCLUSIONS

The results suggest that parent's perceptions of their child's weight are more powerful than objective child body weight in predicting the development of eating disorders. Parent-perceived child overweight was also a specific risk factor for eating disorders, whereas elevated maternal weight and childhood psychosocial difficulties seem to be associated with increased risk for psychiatric disturbance more generally. These results have implications for the prevention of eating disorders, particularly in light of recent increases in the prevalence of childhood obesity.

Neuroscience of anorexia nervosa: state of the art

Recent research in anorexia nervosa has demonstrated specific and persistent neuropsychological deficits associated with specific, localized and unilateral abnormalities on neuroimaging. These point to an underlying neurobiological substrate, with a disconnection in neural circuitry being implicated. This article summarizes the most relevant studies presented at the 9th London International Conference on Eating Disorders and discusses the treatment implications.