Similarities between Eating Disorders and Obesity

Transcription

1 Similarities between Eating Disorders and Obesity Submitted as part requirement for the fulfilment of the degree of Doctorate in Clinical Psychology by Matthew W. Franks MA, MSc, PGDip Psych, BA (Hons) April 2011

2 Declaration This thesis is principally the work of the author, Matthew W. Franks, and has been submitted exclusively as part of the Doctorate in Clinical Psychology (DClinPsy). Signed... Matthew W. Franks ii

3 Abstract This thesis examines the evidence base for psychological interventions for the treatment and prevention of eating disorders and obesity. The research process has three strands. Self-Contained Literature Review This paper considers the literature base for the treatment and prevention of eating disorders through critical appraisal of studies which employed a randomised controlled trial design. The results suggest that the psychopathology of eating disorders is complex and that presentations across diagnoses are variable. The review argues that treatment decisions should not be based on diagnosis alone but on the underlying psychological features of clients who present for treatment through initial screening. Research Report The second strand examines the hypothesis that some of the theories underlying eating disorders may also apply to individuals seeking treatment for obesity by comparing a sample of treatment-seeking obese adults to a sample with eating disorders, and to other group norms. Treatment seeking obese adults in this study were similar to eating disordered populations on measures of external shame, weight concern and shape concern, factors which are believed to be associated with an increased risk of developing an eating disorder. It is suggested that obese clients presenting for weight loss intervention should be screened for levels of shame and eating disordered thoughts and behaviours prior to embarking upon treatment. It is further suggested that for those individuals displaying high levels of shame and eating disordered beliefs/ behaviours, interventions targeting reduction of these constructs by increasing levels of self-compassion may enable some obese clients to lose weight whilst improving psychological wellbeing. It is hypothesised that in contrast to dieting, this may lead to more sustained weight loss and avenues for further investigation of these ideas are considered. Critical Appraisal piece. The research process is considered and learning points discussed in this reflective iii

4 Acknowledgements I would like to thank the participants who took part in this research for their invaluable contribution; without their input this thesis would not have been possible. I would also like to thank my supervisors Dr. Steve Allan and Dr. Ken Goss for their guidance, expertise and support throughout the research process. iv

5 Word Count Main Text Tables References Literature Review 6, ,520 Research Paper 8, Critical Appraisal 2, Non-mandatory Appendices 5,910 Total Thesis Word Count (excluding mandatory appendices) 28,255 v

6 Contents Page Declaration Abstract Acknowledgements Word Count Contents List of Tables List of Figures List of Appendices ii iii iv v vi viii ix x Literature Review What can randomised controlled trials tell us about eating disorders? A systematic review of the efficacy of psychological 1 approaches for prevention and treatment. Abstract 2 1 Introduction Aims and Key Questions 5 2 Method Criteria for considering studies for this review Types of studies Types of participants Types of intervention Types of outcome measures Search methods for identification of studies Data collection and analysis 8 3 Results Internet-Delivered Cognitive Behaviour Therapy Self-help Interventions Treatment Setting and Alternatives to CBT Adaptive Motivational Interviewing and Cognitive Dissonance The Role of Family Underlying psychological factors 19 4 Discussion The Efficacy of Self Help Interventions for Prevention and 21 Treatment of Eating Disorders 4.2 Components and Characteristics of Psychological Therapy: Effects 22 on Treatment Outcome 4.3 Underlying Psychological Factors Strengths and Weaknesses of the Literature Clinical Implications 25 5 Conclusion 27 References 29 Research Paper 36 Can our understanding of obesity be enhanced by considering underlying psychological factors? A cross-sectional study of adults seeking treatment for weight loss. Abstract 37 1 Introduction Obesity and Eating Disorders Shame, Eating Disorders and Obesity Self-Compassion 41 vi

7 Contents Page 1.4 Rationale Study Aims and Objectives 43 2 Method Design Participants Comparison groups Sample Size Measures/ Questionnaires Eating Disorders Examination Questionnaire (EDE-Q) Internalized Shame Scale (ISS) and Other as Shamer Scale 46 (OAS) Self-Compassion Scale (SCS) Procedure Statistical Analysis 48 3 Results Choice of Statistical Tests Reliability of Scales Participant Demographics Relationships Between Scales Analysis of Eating Behaviours Analysis of Shame and Self-Compassion The Effect of Age and Gender Age Gender Summary 63 4 Discussion Eating Behaviour Shame Self-Compassion Clinical Implications Study Limitations Conclusion 72 References 73 Critical Appraisal 80 vii

8 Tables Page Literature Review 1 Summary of Key Study Characteristics 11 Research Report 1 Test for Internal Reliability of Scales 51 2 Pearson Correlations 52 3 TSOA and EDS group means on the EDE-Q 53 4 TSOA and EDEQ-CN Group means on the EDE-Q 55 5 TSOA and BED Group means on the EDE-Q 56 6 TSOA and NEDOP Group means on the EDE-Q 57 7 TSOA and EDS group means on the ISS, OAS and SCS 58 8 TSOA and ISSUP Group means on the ISS 59 9 TSOA and OASUP Group means on the OAS TSOA and CP Group means on the SCS TSOA and EDS group means adjusted for age Summary Data 64 viii

9 Figures Page Literature Review 1 Process of selecting studies for inclusion and number of studies considered at each stage. 9 ix

10 Appendices Page A Literature Review Search Details 88 B Measures for Rating Studies (literature review) 90 C Table of Literature Review Results 92 D Guidelines for Authors for British Journal of Clinical 100 Psychology E Statement of Epistemological Position 103 F Chronology of Research Process 104 G Letters to and from Ethics Committee 105 H Participant Information Sheet 118 I Questionnaires used for the Research Project 121 J z-score Formula and Worked Example 135 x

11 Literature Review What can randomised controlled trials tell us about eating disorders? A systematic review of the efficacy of psychological approaches for prevention and treatment. Target Journal for Publication: British Journal of Clinical Psychology 1

12 Abstract Objective: To update existing literature reviews on randomised controlled trials for eating disorders using a transdiagnostic framework. The primary aim is to understand the psychopathology underlying eating disorders and the resulting implications for treatment approach. Method: A hand-search, reference search, personal contact, and a search of three electronic databases were conducted. A priori inclusion and exclusion criteria were applied to literature from September 2005 to September 2010 to select trials examining psychological interventions for the prevention and/or treatment of eating disorders. Results: Twenty-four studies met the inclusion criteria covering a wide range of psychological interventions. The interaction between underlying client psychopathology and treatment approach appears significant in terms of treatment outcome and supports the argument for a transdiagnostic approach encompassing a number of eating disorder classifications. Conclusion: The efficacy for treatment approaches is variable and presents as dependant on the individual client s therapeutic needs. When deciding upon therapeutic intervention, clinicians should consider underlying psychopathology through rigorous initial assessment as opposed to simply using a blanket approach to treatment based on diagnosis. Keywords: eating disorders; transdiagnostic; psychological treatment; binge eating disorder; anorexia nervosa; bulimia nervosa; eating disorder not otherwise specified; randomised controlled trial; cognitive behavioural therapy; self-help. 2

13 1. Introduction Eating disorders (EDs) are a significant clinical problem in the United Kingdom. An NHS household survey suggested that the prevalence of eating disorders among adults 16 years old and above in the UK is around 6.5%, (McManus et al., 2009). Eating disorder diagnoses include bulimia nervosa (BN), anorexia nervosa (AN) and binge eating disorder (BED). There is also a large proportion of eating disorders which do not fit into DSM-IV criteria, making up the group known as eating disorders not otherwise specified (EDNOS). This group accounts for between 50% and 60% of outpatients presenting with an eating disorder (Fairburn, 2008). It includes significant numbers of people who do not meet the threshold for AN or BN, or have a combination of symptoms of both BN and AN uncharacteristic of either clinical diagnosis (Fairburn, 2008). The literature evaluating treatment for eating disorders suggests variable efficacy. A systematic review of randomised controlled trials (RCTs) investigating the effectiveness of treatments for AN concluded that evidence for the benefits of treatment was weak with the exception of moderately strong results for psychotherapy for adolescents (Bulik, Berkman, Brownley, Sedway, & Lohr, 2007). Trials for BN have demonstrated more success according to another systematic review of RCTs (Shapiro et al., 2007). Medication, medication plus behavioural interventions, and behavioural interventions alone are shown to have a strong evidence base for effectiveness, with less evidence for the efficacy of self-help and other interventions (Shapiro et al., 2007). For BED the evidence from RCTs suggests that medication and medication plus behavioural intervention, and behavioural interventions alone have moderate evidence for effectiveness, with self-help and other interventions showing weak evidence (Brownley, Berkman, Sedway, Lohr, & Bulik, 2007). There is a general consensus in the literature that in order to improve treatments for eating disorders there are a number of complex issues which need further investigation. These include identifying the core pathology of eating disorders (Bulik et al., 2007; Shapiro et al., 3

14 2007) as well as identifying the role of general psychopathology such as obsessive compulsive personality traits (Crane, Roberts, & Treasure, 2007). The application of treatments to specifically target the individual elements of pathology is also crucial for the development of interventions (Brownley et al., 2007). An alternative to treatment based on diagnosis is treatment based on presentation of psychopathological features across diagnoses. The transdiagnostic model of eating disorders (Fairburn, Cooper, & Shafran, 2003) is one such approach, encompassing all classifications of eating disorder. This theory does not distinguish between types of eating disorder, rather it emphasises the idea that eating disorders share a distinctive cognitive pathology: people with eating disorders judge their self-worth largely, or even exclusively, in terms of their shape and weight and their ability to control them (Fairburn, 2008, p. 12). Additional psychopathology characterises each case. Evidence suggests co-morbidity of core eating disorder pathology with anxiety (Grabhorn, Stenner, Stangier, & Kaufhold, 2006), depression (Salbach-Andrae et al., 2008), and obsessive compulsive traits (Wu, 2008). The extent to which these and other factors mediate and moderate the core pathology appears important when considering predisposing factors, maintenance and treatment. Personality factors have been implicated in the emergence and maintenance of eating disorder psychopathology (Thompson-Brenner et al., 2008). Treatments that focus upon selfperception such as mindfulness approaches encouraging participants to develop innerawareness, compassion and self-acceptance show promising results (Proulx, 2008). The success of treatment also appears dependent on client motivation and therapist ability to identify and ally themselves with this motivation (Nordbo et al., 2008). The extent to which interpersonal characteristics affect the quality of the therapeutic alliance also has implications for outcome (Constantino, Arnow, Blasey, & Agras, 2005). The efficacy of self-help for both prevention and treatment of eating disorders has been investigated by a number of studies e.g. Fichter, Cebulla, Quadflieg, and Naab (2008); 4

15 Perkins, Murphy, Schmidt, and Williams (2006). Results suggest that self-help may be an effective adjunct to other modes of treatment in terms of improving outcomes. In particular the role of self-help as a first line prevention strategy to address factors which increase the risk of developing eating disorders such as body dissatisfaction and low self-esteem is of interest as it may provide a relatively low cost and easily disseminated prevention intervention. 1.1 Aims and Key Questions The purpose of this review is to synthesise up-to-date randomised controlled trials investigating the efficacy of psychological interventions for the treatment and prevention of eating disorders. In contrast to the three systematic reviews examining RCTs for pharmacological and psychological treatments of AN (Bulik et al., 2007), BN (Shapiro et al., 2007) and BED (Brownley et al., 2007) this review takes an exclusively psychological and transdiagnostic perspective. A further aim is to update the literature regarding psychological treatments presented in the above reviews. Shortcomings in the literature, clinical implications, and areas for future research are also considered. Two key questions guide the review: What can the literature tell us about the efficacy of psychological interventions for prevention and treatment of eating disorders? What underlying psychopathological features present in people with eating disorders, and how can psychological treatment and prevention strategies best address these? 5

16 2. Method 2.1 Criteria for Considering Studies for this Review Types of studies. All studies observing the following principles were eligible for inclusion: used a psychological intervention for the treatment or prevention of eating disorders; AND used a randomised controlled trial and standardised outcome methodology. Studies examining medication for treatment were excluded as medical treatments were beyond the scope of this review which was specifically concerned with psychological constructs Types of participants. People from the general population with either a DSM-IV diagnosis of anorexia nervosa, bulimia nervosa, binge eating disorder or eating disorder not otherwise specified; those at risk of developing an eating disorder Types of intervention. Cognitive behaviour therapy (including specific adaptations for application to eating disorders e.g. CBT-BN) Family therapy Psychodynamic therapy Self-help therapies (including guided self-help) Types of outcome measures. The following outcome measures are considered important for the area of research in this review (not exhaustive): 6

17 Standardised pre, post intervention and follow-up measures of: general psychological well-being (including measures of mood e.g. Beck Depression Inventory) psychological eating disorder characteristics (e.g. Eating Disorder Exam) physical health (e.g. body mass index) eating disorder clinical diagnosis (DSM-IV criteria) family functioning (e.g. Family Assessment Device) Search methods for identification of studies. In order to capture the widest possible range of studies eligible for inclusion, multiple search strategies were employed. a) Electronic search Three electronic databases were searched - Medline, Web of Science and PsycInfo. Key search terms included a combination of some of the following: eating disorder*, cognitive behavio* therapy, randomi* [controlled trials], psychodynamic, psycholog*. The search was limited to the databases cited based on the results returned, with much of the relevant literature being replicated. See Search details, Appendix A. b) Hand search The International Journal of Eating Disorders was hand searched, September, week 1, 2010 c) Reference search The reference lists of all articles identified through hand and electronic searching were analysed for further relevant material. d) Personal contact A specialist in research for treatment of eating disorders was consulted to identify relevant unpublished studies. 7

18 2.1.6 Data collection and analysis. A scoping search revealed systematic reviews on randomised controlled trials for BED, AN and BN which included studies published up until and including September The search parameters were defined to update the existing literature, with a time overlap included to ensure comprehensive coverage. The articles identified by the electronic searches were screened to remove articles with little or no relevance. One-hundred and eighty-five references were exported to the reference management software, RefWorks. Duplicates were removed, returning eighty-eight references which were combined with relevant results from other search strategies for further analysis. Studies which did not employ randomised controlled trial methodology were excluded. Thirty-five references were returned. Studies from July 2005 (to allow for overlap) to September 2010 were considered for inclusion. The remaining thirty-five studies were rated using multiple measures of quality. The Jadad Scale (Jadad et al., 1996) was used to rate the quality of the RCT methodology. Gough s Weight of Evidence scale (Gough, 2007) was applied to further assess the quality of the studies. The parameters for each of these measures are outlined in Appendix B. Each study was assigned a quality rating: good, fair or poor based on a combination of ratings from both scales. Those studies receiving a poor rating were excluded. The process of study selection is shown in Figure 1. 8

19 Figure 1: Process of selecting studies for inclusion and number of studies considered at each stage. Web of Science = 372 Medline = 201 PsycInfo = 193 SCREENED FOR RELEVANCE TO SUBJECT AREA 185 exported to RefWorks Results 97 duplicates removed; 88 returned, combined with 4 studies form other search methods 35 meet criteria for RCTs 11 excluded due to quality rating; 24 returned for inclusion 9

20 3 Results Of the thirty-five studies eligible for consideration for inclusion, eleven were excluded due to their quality rating or due to not meeting inclusion criteria. The most common reasons for exclusion were a combination of the following: lack of description of randomisation method or use of an inappropriate randomisation method (such as date of birth); no reasons given for dropouts from the study; no method of either single or double blinding; insufficient or no power analysis to determine adequate sample size; no consideration of demographic variations between groups and/or concerns regarding the lack of external validity when applying the results to the general population. The characteristics of the 24 studies included in this review are detailed in Appendix C. The studies were wide ranging in terms of the interventions and psychological constructs under investigation. A summary of key characteristics for the 24 studies is presented in Table 1. Due to the wide variation of results in terms of diagnosis, treatment delivery and therapeutic orientation, studies were grouped under subheadings in the forthcoming results section. This was achieved by selecting studies with common themes and grouping them under these themes in an attempt to capture the breadth and diversity of the literature in a structured and logical manner. 10

21 Table 1: Summary of Key Study Characteristics Sample/ Population Key Statistics Sample Size Range Participant Gender Mean Age Range 18 studies over 90% female 1 study over 80% female 2 studies over 60% female 3 studies gender not specified years Characteristic Number of Studies Diagnosis Anorexia Nervosa Bulimia Nervosa Binge Eating Disorder EDNOS No diagnosis Transdiagnostic Treatment delivery Self-help alone Self-help and personal feedback Guided self-help Therapist administered alone Peer administered Therapeutic orientation CBT-informed Family Therapy Motivational Enhancement Therapy Psychotherapy Dialectical Behaviour Therapy Group Psychodynamic Interpersonal Psychotherapy Cognitive dissonance

22 3.1 Internet-Delivered Cognitive Behaviour Therapy Several of the trials investigated the use of the internet to deliver CBT-based interventions. One trial used internet CBT as a prevention strategy to treat participants with body image concerns (Jacobi et al., 2007). Compared to the no treatment control, the intervention group showed a significant reduction in drive for thinness and weight/ shape concerns, and increased knowledge regarding eating disorders, exercise and healthy eating. These results were maintained at three month follow-up. Of note is the idea that increased knowledge regarding eating disorders and healthy eating can be used as a prevention strategy and does not necessarily lead to increased eating disordered thoughts and behaviours. This is supported by Doyle et al. (2008) which found that using internet-based CBT to aid weight loss was not associated with increased eating disorder behaviours and attitudes, despite the focus on losing weight. One study examining the efficacy of internet CBT for weight loss and a reduction in binge eating found that it was possible to enable weight loss whilst reducing eating disorder psychopathology (Jones et al., 2008). The idea of focussing on weight maintenance as opposed to weight loss is suggested to be important in terms of shifting from a dieting mindset. Of particular interest is the suggestion that by tackling the psychopathology of BED, weight is maintained as a secondary outcome. Internet-based CBT resulted in a significant reduction in weight and shape concern for college age women at risk of developing an eating disorder (Taylor et al., 2006). These results were maintained at one year follow-up and suggest that while overall there was no significant reduction in onset of an eating disorder, there was a reduction in onset in two subgroups those who had baseline compensatory behaviours e.g. laxative use, and those with elevated BMIs at baseline. Furthermore, reduced weight/shape concern in the elevated baseline BMI subgroup was significantly associated with reduction in onset of an eating disorder, suggesting that for this subgroup, targeting weight/ shape concern may be an effective 12

23 intervention for eating disorder prevention. The authors acknowledge that an RCT to investigate this is required to provide more concrete evidence. A trial investigating the use of internet-assisted CBT for the treatment of BED and BN found significant improvement for participants at the end of the twelve week intervention in terms of overcoming binge eating (Ljotsson et al., 2007). These outcomes were maintained at six month follow-up. Those who completed the treatment experienced significantly greater treatment effects than those who did not (31% of participants). There was no reliable predictor of attrition. The evidence presented in these trials suggests that the use of the internet to deliver CBT interventions for the prevention of eating disordered behaviours may be effective in terms of reducing levels of specific risk variables e.g. body image concerns. In addition, these interventions appear to be relatively successful as a first line of treatment for bingeing behaviours characteristic of BN and BED. 3.2 Self-Help Interventions Self-help interventions were utilised and compared to other forms of intervention in many of the trials considered. Streigel-Moore et al. (2010) investigated the use of CBT guided self-help compared to a treatment as usual control and found that the intervention appears to be an effective first line of treatment for patients with recurrent bingeing who do not meet diagnostic criteria for BN or AN. The study was inadequately powered to detect specific outcomes for patients with BN suggesting that this requires more research. A further trial used a CBT self-care CD-ROM to treat participants with BN, with a follow-up of a flexible number of one-to-one CBT sessions (Schmidt et al., 2008). Those in the treatment group had a higher remission rate at three months for binge eating and vomiting but this effect had reversed by seven month follow-up. No significant specific treatment effects were proven. Of those who attended four to eight of the CD-ROM sessions, 68% were in remission from binging, vomiting and laxative misuse at three months, compared to 33% of 13

24 those who attended between zero and four sessions. Those in the treatment group who showed improvement of 50% or more at three months were offered no more than five CBT sessions post-treatment, suggesting the possibility that not enough CBT was provided to maintain the gains shown at three months. Schmidt et al. (2007) found that CBT guided self-help resulted in significantly greater reduction in binge eating after a six month intervention than family therapy but no significant difference for vomiting. The significant difference for binge eating disappeared at twelve months at which point both interventions resulted in significant reduction in binge eating/ vomiting. The mean cost of treatment was significantly lower for the CBT guided self-care intervention. The acceptability of the CBT approach by participants was greater than for family therapy. Cassin et al. (2008) investigated the role of adaptive motivational interviewing (AMI) in the context of self-help interventions for BED. Participants were randomly assigned to AMI + self-help group or a self-help only control. The AMI group showed significantly greater levels of abstinence from binge eating at four, eight and 16 weeks after the intervention compared to the self-help alone control. In terms of the DSM-IV frequency criterion for BED (two or more binges per week), 87% of the AMI group no longer met the criteria compared with 57.4% of the control group and 61% of participants in both groups reported a reduction in the size of their binge eating episodes at 16 weeks. A trial investigating the efficacy of three variations of self-help for BN found that all three had a significant effect on reduction of bulimic symptoms at post treatment and followup, (Steele & Wade, 2008). The trial consisted of three guided self-help (GSH) interventions: CBT for perfectionism, CBT for BN and a mindfulness-based CBT for depression placebo. The trial found that during a no treatment period, there was no significant change in bulimic symptoms. 14

25 Schmidt et al., (2006) investigated the role of personalised feedback in the outcome of CBT guided self-care for BN. Participants had either a DSM-IV diagnosis of BN or eating disorder not otherwise specified (EDNOS) and were randomly allocated to a CBT guided self-care treatment with personalised feedback or a CBT guided self-care treatment only control. Results suggest significant reduction in dietary restraint and self-induced vomiting for the personalised feedback group compared to the control but no significant effect for exercise or bingeing. There was no significant effect of personalised feedback on non-take up of treatment or drop-out rates, with no significant difference between groups. The evidence concerning self-help interventions covered a wide range of different combinations of approaches, and suggested that there are ways of enhancing the effectiveness of these interventions by combining self-help with other techniques such as AMI, personalised feedback and a small number of therapist led CBT sessions. As with the evidence presented for interventions using the internet, these self-help treatments demonstrated levels of efficacy for BN and BED but there is no evidence to suggest that they are being trialled for the treatment of AN. 3.3 Treatment Setting and Alternatives to CBT One trial investigated the effect of treatment setting on outcome for adolescents with AN (Gowers et al., 2007). Participants were randomly assigned to one of three treatment conditions: inpatient, specialist outpatient and general child and adolescent mental health services (CAMHS). At two-year follow-up there was no significant difference between treatment groups. In addition those in the in-patient group had better outcomes if they declined admission for treatment compared to those admitted. Another trial investigated the difference between delivering CBT via telemedicine compared to delivery face-to-face for the treatment of BN and EDNOS, with results not finding a significant difference in outcome between modalities (Mitchell et al., 2008). The authors suggest that, despite reduced ability to detect significant differences between groups 15

26 due to attrition, the results support the idea that interventions delivered via telemedicine may be effective and could increase access to efficacious psychological therapy for targeted and specific psychological difficulties. Robinson and Sarfaty (2008) compared therapist administered bulimia therapy (e-bt) to unsupported self-directed writing (SDC), and a wait list control. Both treatment conditions resulted in significantly lower numbers of participants meeting DSM-IV BN criteria compared to the control. As is the case with many of the studies the level of attrition rendered the trial underpowered to distinguish between the two treatment conditions in terms of specific efficacy factors. A study investigating the use of Dialectical Behaviour Therapy (BDT) compared to an Active Control Group Therapy (ACGT) found no significant difference in terms of treatment efficacy (Safer, Robinson, & Jo, 2010); however DBT displayed a significantly lower dropout rate suggesting that it may be a more acceptable approach for patients. Katzman et al. (2010) compared individual therapy to group therapy and found no significant difference in terms of treatment outcome and no significant difference in dropout rate between conditions. The study also found that motivational enhancement therapy (MET) offered no significant advantage over CBT as a preparation for treatment; however it appears to have been an acceptable alternative to participants as reflected in dropout rates. This suggests that for those who do not engage with a CBT approach, MET may offer an acceptable alternative. These findings have important implications for engagement with clients as they suggest that there are alternatives for those who do not engage with CBT, those who are not suited to a group approach to therapy, and those who are unable to access services but may benefit from interventions delivered through telemedicine and associated new media. 3.4 Adaptive Motivational Interviewing and Cognitive Dissonance Cassin et al. (2008) found that adaptive motivational interviewing (AMI) significantly increased participants ability to resist binge eating when experiencing negative emotions. In addition, although levels of depression and self-esteem showed improvement in both the AMI 16

27 group and the control group, results indicate that the improvement was significantly greater for the AMI group over the 16-week follow-up period. The role of cognitive dissonance has also been identified as a potentially significant factor in terms of prevention of the onset of EDs (Stice, Marti, Spoor, Presnell, & Shaw, 2008). Participants in the dissonance condition showed significantly lower thin-ideal internalisation, body dissatisfaction, negative affect, bulimic symptoms, and psychosocial impairment, than assessment only controls at two year follow-up. At three-year follow-up thin-ideal internalisation and bulimic symptoms results were no longer significant. Overall, dissonance participants showed significantly reduced risk for onset of ED pathology at threeyear follow up. Participants from the healthy weight condition were also at significantly less risk of onset of ED pathology at three year follow-up. The efficacy of cognitive dissonance (CD) was suggested by another trial which compared the use of a CD intervention with a Media Advocacy intervention, and found that over an eight-month period, the CD intervention resulted in significant reductions in restraint, body dissatisfaction, eating pathology and thin-idealisation (Becker, Smith, & Ciao, 2006). Another study comparing three brief interventions also found that CD resulted in the greatest number of participants who were very improved in a non-clinical population (Wade, George, & Atkinson, 2009). Another trial provided a more comprehensive use of a dissonance intervention to address body image concerns in adolescent females and addressed some of the limitations of the previously cited study, such as provision of a measure of treatment fidelity and a larger sample over a one-year follow-up (Stice, Rohde, Gau, & Shaw, 2009). The dissonance intervention showed a significantly greater reduction in ED psychopathology compared to controls both post-treatment and at one year follow-up. 3.5 The Role of Family Three studies addressed the role of family dynamics and eating disorders. Tasca et al. (2006) considered scales of attachment as predictors of outcome of group therapy for 17

28 participants with binge eating disorder assigned to group CBT (GCBT), group psychodynamic interpersonal psychotherapy (GPIP) treatment groups or an assessment only control. Significant interaction effects were found for attachment scale x treatment type and The Need for Approval Scale x treatment type. Results suggested that those with a need for higher approval benefited more from GPIP than GCBT. Family-based treatment (FBT) was compared with supportive psychotherapy (SPT) in a trial investigating treatments for adolescents with BN (le Grange, Crosby, Rathouz, & Leventhal, 2007). The rates of remission for the FBT-BN treatment were significantly higher at posttreatment and six-month follow-up. At midtreatment main effects were more significant for the FBT-BN group across all measures of eating pathology, but not for selfesteem or depression. At posttreatment FBT-BN saw significantly greater reductions in vomiting, compensatory behaviours and EDE (eating disorder exam) restraint. At 6-month follow-up, mean levels for the FBT-BN condition were lower on all EDE indicators, except for subjective binge eating (SBE) but these differences were not significant. The characteristics of different family therapy-based interventions were considered in a trial investigating the treatment of adolescent AN over a five-year follow-up period (Eisler, Simic, Russell, & Dare, 2007). Participants were assigned to either a conjoint family therapy (CFT) treatment, or separated family therapy (SFT) treatment in the original trial, and followed up five years later. In the CFT condition the whole family attended sessions whereas in the SFT condition the child saw the same therapist, but independently to the parents. Results suggested no significant difference in treatment outcome, with 75% of participants displaying no eating disorder behaviours. When considering the role of family interaction in treatment, participants who had received three or more critical comments from their mother during the first assessment interview displayed significantly poorer outcome scores. This association occurred at both posttreatment and 6-month follow-up. There was a statistically significant three-way interaction between type of treatment, expressed emotion (EE) and time. 18

29 Those with high EE in the CFT group did not gain weight to the degree of those with high EE in the SFT group. Those with low EE showed no significant difference in weight gain between treatment groups. These results suggest that the therapeutic environment significantly impacted on clients, in particular adolescents with specific attachment styles and that family dynamics such as high expressed emotion should be considered when selecting a treatment approach. This may reflect the importance of utilising approaches which do not reinforce feelings of shame, an underlying psychological feature characteristic of clients with EDs (Goss & Allan 2009). What is not clear from this evidence is specifically how attachment styles may affect clients with AN or BN and this may be an important consideration for future research. 3.6 Underlying Psychological Factors In addition to the well documented specific psychopathology of over-evaluation of weight and shape, and control of these factors (Fairburn, 2008), a number of studies suggested additional psychopathology which may need to be considered in relation to treatment strategy. Steele and Wade (2008) investigated perfectionism and its impact on BN by testing the hypothesis that a reduction in perfectionism would reduce bulimic symptoms and related psychopathology such as anxiety and depression. Participants were randomly assigned to three guided self-help treatment groups: CBT for perfectionism, CBT for bulimia nervosa, and a mindfulness-based CBT for depression placebo. All three treatment groups showed significant improvement in bulimic symptoms at six-month follow-up, an improvement which did not occur during the non-treatment period before the interventions. Whilst the CBT for perfectionism was not statistically significantly more efficacious than the other interventions, the results suggested that it was at least as effective as CBT for BN and that mindfulnessbased interventions also had a significant impact on reducing eating disorder pathology. Tasca et al. (2006) investigated levels of psychological distress in relation to eating disorder-related attitudes, considering levels of depression and interpersonal problems. 19

30 Participants with BED were randomly assigned to a group CBT condition (GCBT), a group psychodynamic interpersonal psychotherapy condition (GPIP) or an assessment only control group. Each of the treatment conditions showed significant improvement in binge eating compared to the control, or abstinence from bingeing compared to the control at 16-week posttreatment. Levels of interpersonal problems were significantly reduced for both GPIP and GCBT compared to the control at posttreatment. Levels of depression were significantly lower for the GPIP condition compared to the control, but not between GCBT and control, or GCBT and GPIP at posttreatment. Ljotsson et al., (2007) found that internet-assisted CBT led to a 46% improvement in depression for participants with BED and BN. The improvement in symptomology for BED participants was large but this was not the case for the BN group. These results were maintained at six-month follow-up with 44% of participants remaining symptom free. The importance of other psychological factors was considered by another trial comparing an intervention focussed exclusively on ED psychopathology (CBT-Ef) and an intervention addressing additional factors such as clinical perfectionism and mood intolerance (CBT-Eb) (Fairburn et al., 2009). The results suggested that the more complex form should be perhaps reserved for use with clients with marked additional psychopathology as there was no significant difference in outcome between treatment conditions, with both interventions significantly more effective than the control. Specific differences between treatments could not be detected due to attrition resulting in an underpowered sample. There was no significant difference in treatment outcome between diagnostic groups suggesting that distinguishing between BN and EDNOS may not have prognostic utility, supporting the transdiagnostic theory of eating disorders. These results highlight the complexity of psychopathology undying eating disorders and suggest that thorough assessment is important before deciding upon a treatment approach. It appears that levels of depression and other underlying psychological characteristics may be 20

31 targeted more effectively with some ED treatment approaches than with others; what is not clear is, a) how these underlying psychological factors impact upon prognosis for recovery if not explicitly addressed in treatment and, b) which elements of treatment actively address these underlying psychological factors. 4 Discussion The evidence considered provides some important findings for consideration in relation to the review questions which have implications for future research and treatment. 4.1 The Efficacy of Self Help Interventions for Prevention and Treatment of Eating Disorders All CBT-based self-help interventions reviewed for both prevention and treatment showed improvements for participants. These interventions were delivered in a variety of ways, including via the internet and CD-ROM. In terms of prevention a number of studies suggested that CBT combined with psycho-education regarding healthy eating, eating disorders, and a focus on weight management appeared to be useful methods for reducing the levels of core ED psychopathology such as weight and shape concern, and that this may prevent the onset of an eating disorder. This is contrary to the idea that focusing on weight may increase the risk of an ED. Future research investigating the effects on weight/shape concern of a CBT combined with psycho-education and weight management intervention compared to a weight management intervention alone would be a useful addition to the literature in order to further understand the role of CBT and psycho-education in the prevention of EDs. In terms of treatment for people with eating disorders, when CBT self-help is combined with adaptive motivational interviewing (AMI), the evidence from one study suggested that AMI significantly improved outcomes for participants with binge eating disorder, highlighting the importance of considering motivation as a factor affecting treatment outcome (Cassin et al., 2008). Further research is required to both corroborate these findings and to investigate the effects of AMI on other ED diagnoses and other populations. 21

32 Overall the results indicate that the application of self-help for treatment and prevention of BN and BED appeared to have efficacy, particularly when therapist guided; however whether these approaches can be successfully applied to clients with AN warrants further investigation as this appears to be a gap in the literature. 4.2 Components and Characteristics of Psychological Therapy: Effects on Treatment Outcome The majority of studies employed a CBT informed approach and the results suggest that CBT can be successfully used across a variety of treatment modalities including self-help, therapist administered and a combination of the two. This supports the advice from NICE (National Institute of Clinical Excellence) which advocates the use of variations of CBT (among other psychological treatments) for treatment across eating disorder classifications (National Collaborating Centre for Mental Health, 2004). In addition to the successful application of CBT, the studies suggest alternatives or adjuncts to CBT. Several studies demonstrated the successful application of dissonance with one utilising dissonance to challenge internalised ideal-thin schema which demonstrated good evidence for prevention of eating disorder pathology, but also for more general mental health indicators including negative affect (Stice et al., 2008). Treatment setting was investigated in several of the studies presented and the evidence suggested that interventions can be delivered successfully through a number of settings such as telemedicine (Mitchell et al., 2008) and (Robinson & Serfaty, 2008). Differences between in-patient, specialist outpatient and general CAMHS treatment for adolescents with AN demonstrated no significant advantage of one setting over another (Gowers et al., 2007). Consideration of the importance of the engagement and therapeutic relationship were also indicated by a number of the studies. It appears that some approaches may be more acceptable to some clients, for example DBT (Eisler et al., 2007) but there is little consideration of specific mediators and moderators of successful engagement. There is also 22

33 little consideration of the relationship between motivation to engage and dropout rates. These factors appear to be important for consideration in further research as understanding factors affecting engagement, motivation and dropout are likely be important in terms of assessing the treatment approach most suited to individuals. 4.3 Underlying Psychological Factors One trial indicated that treatment for underlying psychological distress may be at least as effective as specific targeting of eating disorder pathology (Steele & Wade, 2008). This evidence supports a transdiagnostic approach to eating disorders which suggests that mood intolerance (including depressive states) plays a significant role in onset and maintenance of eating disorders (Fairburn et al., 2003). This idea is further supported by the fact that CBT for perfectionism was also shown to be as effective as both CBT-BN and CBT for depression (Steele & Wade, 2008). This supports the idea that perfectionism is also a potentially significant factor underlying a transdiagnostic approach. Further research is required to investigate the dynamics of this relationship. For clients with more complex presentations such as a combination of core eating disorder pathology and clinical perfectionism, Fairburn et al. (2009) suggested that a more complex form of the standard CBT-E treatment is at least as effective as the standard form and that it may be more effective for those with complex presentations. More evidence is required to support this hypothesis, and an adequately powered study comparing outcomes for those with more complex presentations receiving either the standard or more complex version of treatment would be welcomed. The importance of interpersonal factors, particularly family relationships also appears significant when considering treatment of eating disorders. Three trials demonstrated the efficacy of family-based treatment across the spectrum of eating disorders. In particular there appears to be a relationship between type of treatment and family characteristics in terms of the effect on treatment outcome. Participants diagnosed with BED, with high attachment 23

34 anxiety were more likely to benefit from a group psychodynamic interpersonal approach (GPIP) than a group CBT approach (GCBT) (Tasca et al., 2006) suggesting that the mechanisms of attachment have an effect upon the ability to engage in different forms of therapy. This has implications for initial assessment of clients as the results suggest that participant characteristics are likely to have a significant impact on treatment choice and outcome. This hypothesis is supported by the findings of Eisler et al. (2007). They found that high expressed emotion (EE) in families was associated with poorer outcomes for familybased treatment of adolescent anorexia nervosa suggesting that those with high EE families may benefit from therapy which does not directly involve other family members such as CBT or separated family therapy. The idea that interpersonal relationships play a significant role in eating disorder pathology is supported by research suggesting that interpersonal issues such as a need for control in a family environment can lead to the need for control being shifted to control over eating behaviours (Fairburn, Shafran, & Cooper, 1999). These family-based treatment trials add further weight to the argument for a transdiagnostic model. 4.4 Strengths and Weaknesses of the Literature The literature selected for inclusion utilised the gold standard clinical design, the randomised controlled trial (RCT). All trials included were selected on the basis of robust study design characteristics such as adequate sample size, (with power calculations to ensure adequacy), measures of bias and attrition rates. It is however noted that sample sizes would ideally be higher than those in some studies (see Appendix C for details of study limitations). The literature provides a substantial addition to the RCT for eating disorders knowledge base. There were however areas of weakness in the literature. Most studies did not use single blinding and none used double blinding. Placebo controls are difficult to implement with maximum validity due to the ethical need to treat symptoms causing significant distress 24

35 to patients; however it remains a problem in terms of limitations of this form of study. For this reason analysis of studies which employ other methodologies and designs would be a useful area for future review. Whilst the majority of studies selected for inclusion were explicit in their description of randomisation and used appropriate randomisation techniques, some were not explicit as to the method used for randomisation. The search did not identify any RCTs investigating the role of ethnicity in treatment as a primary focus. The majority of studies recruited samples which were over 90% female with no trials specifically focusing on males with eating disorders. Trials used an excessively wide range of different diagnostic and outcome measures which complicates comparison of outcomes between studies, a weakness previously identified by Shapiro et al. (2007). The number of trials addressing anorexia nervosa were noticeably underrepresented in the results and this is consistent with the findings of the systematic review by Bulik et al. (2005) which concluded that there were deficiencies in the quality of the AN literature, suggesting that further quality research in this area is required. The literature was dominated by studies investigating CBT and other psychological therapies appeared under-represented. Meta-analyses of study results investigating specific themes discussed here would be a useful next step to understanding more about treatment effects. Combination of the results to measure effect size for specific variables, depending on research objectives, would provide further information which would strengthen the literature base. 4.5 Clinical Implications Whilst the evidence for CBT approaches was the strongest for all approaches considered, this review suggested that characteristics within any approach to treatment, for example, the use of guided self-help and/or family involvement, were equally important as the theoretical basis for intervention. Client characteristics such as affect, perfectionism, and motivation appear to play a significant role, re-emphasising the importance of the initial 25