Predictors of outcome in cognitive behavioural therapy for eating disorders: An exploratory study

Predictors of Treatment Outcome in Eating Disorders: A Roadmap to Inform Future Research Efforts

PURPOSE OF REVIEW

With the current review, we provide a brief summary of recent literature that tests clinically observable characteristics at baseline that may impact treatment response, across eating disorder diagnoses. We then provide a critical discussion regarding how researchers may shift their approach to this research to improve treatment implications and generalizability of these findings.

RECENT FINDINGS

Recent work has broadly replicated prior findings suggesting a negative impact of lower weight status, poor emotion regulation, and early-life trauma on eating disorder treatment outcomes. Findings are more mixed for the relative contributions of illness duration, psychiatric comorbidity, and baseline symptom severity. Recent studies have begun to explore more specific domains of previously tested predictors (e.g., specific comorbidities) as well as previously neglected identity-related and systemic factors. However, recent research continues to use similar sampling techniques and approaches to analysis used in prior work. We propose that resolving remaining questions and illuminating predictors of treatment outcome in eating disorders requires a new approach to research sampling and study design. Suggested changes that can be applied within a traditional clinical trial framework may yield new insights with relevance across transdiagnostic eating disorder presentations.

Understanding the role of positive body image during digital interventions for eating disorders: Secondary analyses of a randomized controlled trial

Despite growing interest in the possible link between positive body image and eating disorder (ED) symptoms, little is known about what role this adaptive construct plays in ED treatment. This study investigated whether: (1) interventions principally designed to target ED psychopathology also lead to improvements in positive body image indices (i.e., body appreciation, functionality appreciation, and body image flexibility); (2) changes in ED symptoms correlate with changes in positive body image, both concurrently and prospectively; and (3) baseline positive body image levels moderate the degree of symptom improvement. Secondary analyses from a randomized controlled trial on digital interventions for EDs (n=600) were conducted. Intervention participants reported greater increases in the three positive body image constructs than the control group (ds=0.15-0.41). Greater pre-post reductions in ED psychopathology and binge eating were associated with greater pre-post improvements in positive body image indices. However, earlier reductions in ED psychopathology and binge eating did not predict later improvements in positive body image at follow-up. None of the positive body image constructs at baseline moderated degree of symptom change. Standard ED interventions can cultivate a more positive body image, although this is not explained by earlier symptom reduction. Understanding the mechanisms through which ED interventions enhance positive body image is needed.

Alliance matters: but how much? A systematic review on therapeutic alliance and outcome in patients with anorexia nervosa and bulimia nervosa

PURPOSE

Patients with eating disorders (ED) pose a high-risk group regarding relapse. The understanding of factors contributing to a better outcome is much-needed. Therapeutic alliance (TA) is one important, pantheoretical variable in the treatment process, which has shown to be connected with outcome. This review looks into a possible predictive effect of TA on outcome as well as related variables.

METHODS

A systematic review with pre-determined inclusion criteria following the PRISMA guidelines was conducted for studies published since 2014. Three previous reviews including studies up until 2014 were analyzed for studies matching our inclusion criteria. A total of 26 studies were included.

RESULTS

The results were heterogeneous between different patient groups. Regarding the predictive effect of TA, in adolescent samples, the TA of either the patients or their parents seems to impact outcome as well as completion. For adults, results are mixed, with a tendency to a greater impact of TA for anorexia nervosa (AN) patients, while some samples of adult bulimia nervosa (BN) patients did not find any relation between TA and outcome.

CONCLUSION

The effect of TA on clinical outcome depends on the patient group. TA has a greater impact on adolescents, irrespective of diagnosis, and on adults with AN. The examined studies have different limitations which include small sample sizes and questionable study design. The examination of motivation as a potential influencing factor is recommended.

LEVEL OF EVIDENCE

Level I, systematic review.

Predictors of Symptom Trajectories After Cognitive-Behavioral Therapy in Adolescents With an Age-Adapted Diagnosis of Binge-Eating Disorder

Although evidence demonstrated efficacy of cognitive-behavioral therapy (CBT) in adolescents with binge-eating disorder (BED), treatment response is heterogeneous. This study uniquely examined baseline predictors of symptom trajectories in N = 73 adolescents (12-20 years) with an age-adapted diagnosis of BED (i.e., based on objective and subjective binge-eating episodes). Based on evidence from adult BED, dietary restraint, overvaluation of weight/shape, and depressive symptoms were used to predict changes in abstinence from binge eating and eating disorder psychopathology after 4 months of individual, face-to-face CBT using growth models. Longitudinal trajectories of abstinence from objective and subjective binge eating and global eating disorder psychopathology assessed via the Eating Disorder Examination were modeled for five time points (pre- and posttreatment, 6-, 12-, and 24-month follow-up). Beyond significant, positive effects for time, no significant predictors for abstinence from binge eating emerged. In addition to significant decreases in eating disorder psychopathology over time, higher pretreatment dietary restraint and overvaluation of weight/shape significantly predicted greater decreases in eating disorder psychopathology over time. Consistent with research in adult BED, adolescents with higher than lower eating disorder-specific psychopathology especially benefit from CBT indicating that restrained eating and overvaluation of weight/shape may be BED-specific prognostic characteristic across developmental stages. Future predictor studies with an additional focus on potential age-specific predictors, such as family factors, and within-treatment processes may be critical in further evaluating treatment-related symptom trajectories in adolescent BED.

Positive body image, intuitive eating, and self-compassion protect against the onset of the core symptoms of eating disorders: A prospective study

OBJECTIVE

Establishing factors that protect against the onset of eating disorder symptoms is needed to identify critical intervention targets to inform the design of more potent prevention programs. Knowledge of robust protective factors is lacking, which might account for the limited effectiveness of existing prevention programs. As positive body image, intuitive eating, and self-compassion show protective potential, the present study tested whether these factors protect against the onset of a range of different eating disorder symptoms.

METHOD

Data were analyzed from 1,270 women who completed study measures at baseline and 8 months. Logistic regressions tested whether, among initially asymptomatic women, baseline and changes in positive body image components (body appreciation, body image flexibility, and functionality appreciation), intuitive eating, and self-compassion predicted the continued absence versus onset of seven core eating disorder symptoms at follow-up.

RESULTS

Each of the five factors at baseline was associated with a lower odds of symptom onset for each outcome in univariate analyses. Baseline body appreciation and intuitive eating scores remained consistent, unique predictors of a lower odds of experiencing symptom onset in multivariate models. Greater increases in intuitive eating and body appreciation over time were the two factors consistently associated with a lower odds of symptom onset across several outcomes.

DISCUSSION

This study provides strong evidence for the protective influence of positive body image components, intuitive eating, and self-compassion against several eating disorder symptoms. Building these factors within established prevention programs may, in the longer term, help reduce the incidence of eating disorder syndromes and symptoms.

Can early change in eating disorder psychopathology predict outcome in guided self-help for binge eating?

PURPOSE

This study tests the value of a measure of eating disorder (ED) psychopathology in predicting outcome following guided self-help in a non-underweight sample with regular binge eating. It examines whether early reductions in ED psychopathology are associated with remission status at post-treatment.

METHODS

Seventy-two adults with bulimia nervosa, binge-eating disorder, or an atypical form of these illnesses received up to ten sessions of cognitive behaviour therapy-based guided self-help. Using a session-by-session measure of eating pathology and associated reliable change indices, response was analysed using receiver operating characteristic analysis to predict outcomes at post-treatment.

RESULTS

In this routine care setting, nearly one-quarter of the sample achieved remission following GSH, approximately two-thirds of whom showed early change in ED psychopathology. Early change prior to session 6 was accurate in predicting later remission. Individuals showing early change did not differ from others on baseline characteristics or rates of attrition.

CONCLUSION

Data suggest that a majority of those who respond to treatment will do so before the second half of treatment, information that could be used to ensure that evidence-based treatments are used as effectively as possible.

LEVEL OF EVIDENCE

Level III.

Early response to psychological treatment for eating disorders: A systematic review and meta-analysis

Early response is a well-established predictor of positive outcomes at the end of psychological treatments for common mental disorders. There is some prior evidence that this conclusion also applies to eating disorders, including three meta-analyses, but no moderators of that relationship have been identified. However, a number of further papers have been published since, which might influence the size of the effect of early response or the potential role of moderating factors. This pre-registered systematic review presents a comprehensive examination of this literature. Three databases were searched (Scopus, PsycInfo, PubMed). In total, 33 eligible studies were included in a narrative synthesis, and 25 studies were included in random-effects meta-analysis. The majority (91%) of studies were rated as having low or moderate risk of bias. Approximately half of patients across clinical samples showed early response to psychological therapy, which was most often defined as reliable symptomatic improvement during the first four sessions. A significant and moderate association was found between early response and post-treatment outcomes (r = 0.41 [95% CI: 0.32-0.481], p < .0001). Significant evidence of heterogeneity (Q[28] = 136.42, p < .0001; I² = 80.2%) was evident. The review was limited by the exclusion of grey literature and only 76% of studies provided sufficient statistical information for meta-analytic synthesis, although we found no significant evidence of publication bias, χ²(1) = 0.001, p = .97. Overall, evidence accumulated over twenty years establishes early response as the most robust predictor of treatment outcomes in the field of eating disorders. However, only half of patients show early change in this way. Further research is needed to determine whether there are patient or clinician characteristics that predict early response to psychological treatment for eating disorders.

Approach and avoidance bias for thin-ideal and normal-weight body shapes in anorexia nervosa

OBJECTIVE

The two studies aimed to examine implicit affective evaluations of thin-ideal and normal-weight body shapes in women with anorexia nervosa (AN), taking identification with body shapes into account.

METHOD

In study 1, approach-avoidance bias for thin-ideal and normal-weight bodies was assessed in 40 women with AN and 40 healthy women by using an Approach-Avoidance Task and female avatar bodies with a standard face as stimuli. In study 2, 39 women with AN and 38 healthy women underwent a similar task but identification with bodies was manipulated by presenting bodies once with the participant's own face and once with another woman's face.

RESULTS

In study 1, patients with AN did not differ from healthy participants in their automatic approach-avoidance tendencies towards thin-ideal and normal-weight bodies. In study 2, no definite approach bias for a thin self and no avoidance bias for thin other women or for a normal-weight self were found. However, as compared to healthy women, those with AN showed a less positive implicit evaluation of thin other women, and an implicit preference for thin bodies depicted as themselves over thin bodies depicted as another woman.

CONCLUSIONS

The findings suggest that intra-sexual competition for being slim is increased in AN.

Internalized Weight Bias and Disordered Eating: The Mediating Role of Body Image Avoidance and Drive for Thinness

Internalized weight bias has been linked with undesirable physical and psychological health outcomes, including disordered eating. Interventions have targeted internalized weight bias and associated outcomes, but little is known about underlying mechanisms of change. Existing treatment literature suggests that drive for thinness and body image avoidance may sustain the link between internalized weight bias and disordered eating. The present study aimed to determine if drive for thinness and body image avoidance mediated the relationship between internalized weight bias and disordered eating in an ethnically diverse sample. Participants included 225 female college students aged 18–49 years (mean age = 20.4 years, SD = 4.4), with a mean BMI of 23.3 kg/m² who completed a computer-based survey for partial course credit. As expected, internalized weight bias was positively associated with disordered eating, and results supported the hypothesis of the mediating role of drive for thinness and body image avoidance. These results are important given the shortage of intervention efforts targeting internalized weight bias. Future intervention efforts aimed at reducing internalized weight bias and associated outcomes may benefit from simultaneously targeting drive for thinness and body image avoidance.

Comparing a Tailored Self-Help Mobile App With a Standard Self-Monitoring App for the Treatment of Eating Disorder Symptoms: Randomized Controlled Trial

BACKGROUND

Eating disorders severely impact psychological, physical, and social functioning, and yet, the majority of individuals with eating disorders do not receive treatment. Mobile health apps have the potential to decrease access barriers to care and reach individuals who have been underserved by traditional treatment modalities.

OBJECTIVE

The objective of this study was to evaluate the effectiveness of a tailored, fully automated self-help version of Recovery Record, an app developed for eating disorders management. We examined differences in eating disorder symptom change in app users that were randomized to receive either a standard, cognitive behavioral therapy-based version of the app or a tailored version that included algorithmically determined clinical content aligned with baseline and evolving user eating disorder symptom profiles.

METHODS

Participants were people with eating disorder symptoms who did not have access to traditional treatment options and were recruited via the open-access Recovery Record app to participate in this randomized controlled trial. We examined both continuous and categorical clinical improvement outcomes (measured with the self-report Eating Disorder Examination Questionnaire [EDE-Q]) in both intervention groups.

RESULTS

Between December 2016 and August 2018, 3294 Recovery Record app users were recruited into the study, out of which 959 were considered engaged, completed follow-up assessments, and were included in the analyses. Both study groups achieved significant overall outcome improvement, with 61.6% (180/292) of the tailored group and 55.4% (158/285) of the standard group achieving a clinically meaningful change in the EDE-Q, on average. There were no statistically significant differences between randomized groups for continuous outcomes, but a pattern of improvement being greater in the tailored group was evident. The rate of remission on the EDE-Q at 8 weeks was significantly greater in the group receiving the tailored version (d=0.22; P≤.001).

CONCLUSIONS

This is the first report to compare the relative efficacy of two versions of a mobile app for eating disorders. The data suggest that underserved individuals with eating disorder symptoms may benefit clinically from a self-help app and that personalizing app content to specific clinical presentations may be more effective in promoting symptomatic remission on the EDE-Q than content that offers a generic approach.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02503098; https://clinicaltrials.gov/ct2/show/NCT02503098.