Predictors, mediators, and moderators of response to digital interventions for eating disorders: A systematic review

Thinking flexibly about who digital mental health interventions are for and how they should be evaluated and used: Commentary on McClure et al. (2023)

Less than 20% of individuals with eating disorders (EDs) ever receive treatment. Digital interventions offer one solution to this problem and have demonstrated promise, but there is a need to understand predictors, moderators, and mediators of response, which McClure and colleagues aimed to do in their systematic review. Yet their review also raised key definitional and measurement issues pertinent to conducting research on digital interventions for EDs and other mental health problems, which may have impacted the conclusions drawn and which may stem from applying what has "always been done" in research on more traditional psychological interventions to research on digital interventions. This commentary suggests that digital interventions for EDs and other mental health problems should not be conceived as a 1:1 replacement for individual psychotherapy, and rather, these interventions should be viewed as one option in a wide-ranging menu of services that should be available, as the reality is that not all individuals want or can access the same type of care. If we accept that digital interventions need not be viewed as a 1:1 replacement for psychotherapy, then it logically follows that we should not evaluate or use these two approaches in the exact same manner.

Prevention of eating disorders: 2023 in review

This review of 16 prevention-related publications in Eating Disorders during 2022 is framed by three models: (1) Mental Health Intervention Spectrum: health promotion → types of prevention → case identification/referral → treatment; (2) the prevention cycle: rationale and theory, shaped by critical reviews → clarifying risk and protective factors → program innovation and feasibility studies → efficacy and effectiveness research → program dissemination; and (3) definitions of and links between disordered eating (DE) and eating disorders (EDs). Seven articles fell into the category of prevention rationale (including screening studies) and relevant reviews, while nine articles addressed correlates of/risk factors (RFs) for various aspects of DE and EDs. One implication of the 16 articles reviewed is that RF research toward construction of selective and indicated prevention programs for an expanding array of diverse at-risk groups needs to address, from a nuanced, intersectional framework, a broad range of factors beyond negative body image and internalization of beauty ideals. Another implication is that, to expand and improve current and forthcoming prevention programs, and to shape effective advocacy for prevention-oriented social policy, the field in general and Eating Disorders in particular need more scholarship in the form of critical reviews and meta-analyses; protective factor research; prevention program development and multi-stage evaluation; and case studies of multi-step activism at the local, state (province, region), and national levels.

Envisioning an improved research strategy for detecting moderators/mediators in intervention studies: A commentary on McClure et al

The goal of moderator/mediator research in treatment evaluation is to provide guidance to clinicians to choose the best treatment for each patient with a disorder (moderators), and to advise on its optimal protocol or implementation (mediators): personalized/precision medicine. McClure et al. report a systematic review of studies addressing moderators/mediators of the treatment effect of digital interventions for eating disorders, finding no robust moderators or mediators. They attribute this failure to methodological problems, an assessment with which I concur. The focus of this discussion is to clarify which methodological approaches are not likely to be successful, and to envision a research strategy encompassing both hypothesis-generating (exploratory) and hypothesis-testing approaches likely to produce better results not only for eating disorders, but also for all medical treatments.

Timing matters in (mis)identifying moderators and mediators of digital interventions for eating disorders: Commentary on McClure et al. (2023)

This commentary addresses the challenges in identifying consistent moderators and mediators of psychological treatments for eating disorders (EDs), as highlighted by McClure et al. (International Journal of Eating Disorders, 2023) in their systematic review. Specifically, we discuss the often-overlooked importance of temporal context (when an intervention is delivered), alongside sociodemographic and symptom type (for whom an intervention is delivered), in understanding and optimizing treatment engagement and effectiveness. We outline how individuals' fluctuating levels of motivation and receptivity across different "pivotal moments" in the help-seeking process-including initial outreach and self-screening, ongoing care engagement, and post-discharge-can dynamically impact interventions' relevance and impacts. We also overview how Just-In-Time Adaptive Interventions in digital mental health interventions can be harnessed to simultaneously consider "when" and "for whom" ED interventions can exert the greatest benefits. We conclude with several recommendations for conducting ED intervention and implementation research that integrate timing into support delivery and study design, enabling a deeper understanding of not just how and for whom, but when, ED interventions can be most effective.

Exploration of the individual and combined effects of predictors of engagement, dropout, and change from digital interventions for recurrent binge eating

OBJECTIVE

Our ability to predict responsiveness to digital interventions for eating disorders has thus far been poor, potentially for three reasons: (1) there has been a narrow set of predictors explored; (2) prediction has mostly focused on symptom change, ignoring other aspects of the user journey (uptake, early engagement); and (3) there is an excessive focus on the unique effects of predictors rather than the combined contributions of a predictor set. We evaluated the univariate and multivariate effects of outcome predictors in the context of a randomized trial (n = 398) of digitally delivered interventions for recurrent binge eating.

METHOD

Thirty baseline variables were selected as predictors, ranging from specific symptoms, to key protective factors, to technological acceptance, and to online treatment attitudes. Outcomes included uptake, early engagement, and remission. Univariate (d) and multivariate (D) standardized mean differences were calculated to estimate the individual and combined effects of predictors, respectively.

RESULTS

At the univariate level, few predictors produced an effect size larger than what is considered small (d > .20) across outcomes. However, our multivariate approach enhanced prediction (Ds = .65 to 1.12), producing accuracy rates greater than chance (63%-71% accuracy). Less than half of the chosen variables proved to be useful in contributing to predictions in multivariate models.

CONCLUSION

Findings suggest that accuracy in outcome prediction from digitally delivered interventions may be better driven by the aggregation of many small effects rather than one or several largely influential predictors. Replication with different data streams (sensor, neuroimaging) would be useful.

PUBLIC SIGNIFICANCE

Our ability to predict who will and will not benefit from digital interventions for eating disorders has been poor. We highlight the viability of a multivariate approach to outcome prediction, whereby prediction may be better driven by the aggregation of many small effects rather than one or a few influential predictors.

We need to be more critical toward digital interventions for eating disorders: A commentary on McClure et al. (2023)

Over the past two decades, numerous digital interventions (also referred to as "e-mental health" interventions) have been developed for the prevention and treatment of eating disorders and several meta-analyses have summarized the existing evidence on the efficacy and effectiveness of such interventions. Based on the present systematic review of McClure and Colleagues, the question of how and for whom digital interventions for eating disorders actually work, remains unanswered. In the absence of reliable mediators and moderators of outcome, priorities for future research are discussed (e.g., a need for more rigorous RCTs with credible comparators). The resulting research agenda is expansive. However, even though this process will take time and might seem slow (especially, in contrast to the rapidity of technological developments), we should not accept a lowering of the quality bar in research on digital interventions compared to other intervention research.

A randomized controlled trial of an online single session intervention for body image in individuals with recurrent binge eating

OBJECTIVE

Theoretical models highlight body image disturbances as central to the maintenance of eating disorders, with empirical evidence finding negative body image to be a robust predictor of treatment nonresponse, relapse and symptom persistence. Accessible, scalable, and inexpensive interventions that can effectively target negative body image across the eating disorders are needed. We developed an online single session intervention (SSI) for negative body image and evaluated its acceptability and efficacy in a randomized controlled trial in individuals with recurrent binge eating.

METHOD

Participants with recurrent binge eating were randomly assigned to the SSI (n = 99) or a waitlist (n = 101). Assessments were conducted at baseline, 4 week follow-up, and 8 week follow-up.

RESULTS

81% of participants accessed the SSI, demonstrating reasonable uptake. However, issues with attrition were apparent; a 32% study dropout rate was observed at posttest, while a 58% dropout rate was observed at follow-up. 87% of participants who completed satisfaction measures would recommend the SSI. SSI participants experienced greater improvements in negative body image at both 4 (d = -0.65) and 8 week (d = -0.74) follow-up. Significant between-group effects were also observed on most other secondary symptom measures, though no differences were found for motivations and help-seeking beliefs and intentions.

CONCLUSION

Body image-focused self-guided SSIs for recurrent binge are largely accepted by those who are retained in the trial, but are associated with significant attrition. Although SSIs are not intended to replace standard treatment, they may help with short-term symptom management and could play an important role in eating disorder care.

PUBLIC SIGNIFICANCE

Single session interventions (SSI) are a potentially accessible, scalable, and cost-effective way to deliver evidence-based treatment content to people with eating disorders. This study shows that an online (SSI) designed to target body image among people with recurrent binge eating is accepted and produced short-term symptom relief.

Digital Mental Health Interventions: Differences in Diet Culture Intervention Framing

Diet culture is a societal norm that ranks thin bodies as superior to other body types and has been associated with negative outcomes, such as eating disorders. Wellness has evolved into a term that is often used to promote diet culture messages. One possible way to combat diet culture is through single-session, digital mental health interventions (DMHIs), which allow for increased access to brief public health treatments. The framing of DMHIs is critical to ensure that the target population is reached. Participants (N = 397) were enrolled in a single-session DMHI, which was framed as either a Diet Culture Intervention (n = 201) or a Wellness Resource (n = 196). Baseline group differences in eating disorder pathology, body image, weight stigma concerns, fat acceptance, and demographic characteristics were analyzed. Across groups, participants reported moderately high eating disorder pathology, low-to-moderate levels of body dissatisfaction, moderate levels of fat acceptance, and either very low or very high weight stigma concerns. Participants in the Diet Culture Intervention group reported higher levels of fat acceptance than those in the Wellness Resource group (p < 0.001). No other framing group differences were identified, though post hoc analyses revealed differences based on recruitment source (i.e., social media versus undergraduate research portal). This study found that framing a DMHI as targeting diet culture or as a Wellness Resource can result in the successful recruitment of individuals at risk of disordered eating. Framing a DMHI as a Wellness Resource may increase recruitment of individuals with low levels of fat acceptance, which may be particularly important for dismantling diet culture, disordered eating, and weight stigma concerns. Future research should assess DMHI framing in other populations, such as men and adolescents.