Mapping a Decade of Eating Disorder Therapy Trials Reveals Gaps and Small Studies

Psychological therapies are the frontline treatment for eating disorders, yet the evidence base supporting them has never been fully charted since psychiatry adopted its current diagnostic manual more than a decade ago. A new systematic scoping review, published in the Journal of Eating Disorders, has now mapped every randomized controlled trial of psychological treatments for eating disorders diagnosed under the DSM-5 and DSM-5-TR criteria, covering studies published between January 2013 and April 2026. The result is both encouraging and sobering: the field is producing more trials than ever, but most of that research remains small, short, exploratory, and narrowly focused on a handful of diagnoses and patient groups.

The research team, led by Liyun Zheng and colleagues at Peking University Sixth Hospital and the Peking University Institute of Mental Health, searched four major bibliographic databases—PubMed, PsycINFO, Embase, and the Cochrane Central Register of Controlled Trials—for randomized trials evaluating psychological interventions in patients diagnosed according to the updated diagnostic criteria. Unlike a traditional meta-analysis, which pools numerical results to estimate treatment effects, a scoping review aims to characterize the shape of an entire literature: who has been studied, with which therapies, against which comparators, and with what outcomes. That distinction matters here, because the authors argue that previous reviews of eating disorder psychotherapy have concentrated almost exclusively on efficacy while leaving the design and reporting quality of the underlying trials largely unexamined.

The search yielded 81 randomized controlled trials. Publication activity increased steadily across the periods covered by the review, a sign that the field has grown since the DSM-5 replaced the older DSM-IV framework in 2013. That diagnostic shift was significant for eating disorder research: it introduced binge-eating disorder as a formal diagnosis, created the category of avoidant/restrictive food intake disorder, and reorganized the residual categories of feeding and eating disorders. Each of those changes altered which patients could be enrolled in trials and how researchers framed their studies, making a fresh map of the trial landscape overdue.

What the map reveals first is a problem of generalizability. Most of the 81 trials were conducted in Western countries, and the participants were predominantly adult women. Eating disorders do, in reality, affect men, adolescents, older adults, and people across many cultural and geographic settings, but the trial evidence overwhelmingly reflects a narrow slice of that population. For clinicians treating patients outside that slice, the evidence base offers limited direct guidance, and the review’s authors highlight broadening participant populations as a priority for future research.

The scale of individual studies is another striking finding. More than half of the trials enrolled fewer than 100 participants, and 30 of the 81 were explicitly pilot or feasibility studies—early-stage investigations designed to test whether a larger trial is workable rather than to establish whether a treatment works. Long-term evidence is similarly thin: 69 of the trials followed participants for twelve months or less, meaning that questions about whether therapeutic gains persist, erode, or emerge only years after treatment remain largely unanswered. Attrition compounds the problem, because dropout from end-of-treatment assessments frequently exceeded 20 to 30 percent, a rate high enough to threaten the validity of comparisons even in well-designed studies.

The diagnostic distribution of the trials is strikingly lopsided. Binge-eating disorder appeared in 48 trials, making it by far the most intensively studied condition in the DSM-5 era, while anorexia nervosa and bulimia nervosa—historically the core of the field—received comparatively less experimental attention in this sample. At the other extreme, avoidant/restrictive food intake disorder, a diagnosis that describes restrictive eating not driven by body-image concerns, was addressed in exactly one trial. No eligible trials at all examined pica or rumination disorder, and unspecified feeding or eating disorder appeared only within mixed diagnostic samples. For patients with these less common presentations, randomized evidence for psychological treatment is essentially absent.

On the treatment side, cognitive-behavioral approaches dominated, appearing in 45 of the 81 trials. This family of therapies, including enhanced cognitive behavioral therapy, targets the thoughts and behaviors that maintain disordered eating, and its prominence reflects decades of accumulated support. Other modalities—interpersonal psychotherapy, dialectical behavior therapy, family-based treatment, mentalization-based treatment, and acceptance and commitment therapy among them—were represented but far less frequently. The review also found that digital interventions, a rapidly growing area that promises to expand access to care, were usually tested against waitlist controls rather than against active treatments already in use. That design choice is a known weakness: showing that an app or online program outperforms doing nothing says little about whether it outperforms face-to-face therapy or standard clinical management, which is the comparison patients and health systems actually face.

Measurement practices revealed further blind spots. Trial outcomes concentrated heavily on eating disorder symptoms, such as binge frequency and restraint, while outcomes that matter to patients, families, and health services—caregiver burden, quality of life beyond symptoms, costs, and resource use—were rarely assessed. Methodological reporting was also incomplete in important respects. Fifty-five trials did provide a qualifying sample-size rationale, a positive signal for statistical planning, but allocation concealment, the safeguard that prevents those enrolling patients from knowing the next assignment, was often not fully described. Treatment fidelity—whether the therapy was actually delivered as intended—and the monitoring of harms or adverse effects also remained incompletely reported across much of the literature. These gaps matter because readers cannot judge the credibility of a trial’s results if they cannot verify how it was conducted.

The authors’ conclusions are measured but pointed. The randomized literature on psychological treatments for eating disorders is expanding, they write, yet it remains largely exploratory in character. Their recommendations for the next generation of trials read as a checklist for maturing the field: enroll broader and more diverse populations, extend coverage to neglected diagnoses such as ARFID, pica, and rumination disorder, compare new treatments against active care rather than waitlists, measure outcomes that patients and service providers actually value, and commit to prospective registration with complete reporting of methods and safety. None of these changes requires a scientific breakthrough; they are questions of design discipline and reporting standards.

For the millions of people affected by eating disorders worldwide, the practical takeaway is nuanced. The review does not undermine the treatments clinicians use today—cognitive behavioral therapy in particular rests on a substantial body of work—but it clarifies how much of that work rests on small, short studies in narrow populations. As digital therapeutics and novel psychological models multiply, this evidence map provides the field with a baseline: a clear picture of where the randomized evidence stands in the DSM-5 era, and a blueprint for the trials that will determine whether the next decade of eating disorder research finally delivers answers that generalize to the full range of patients who need them.

Subject of Research: A scoping review of randomized controlled trials of psychological treatments for eating disorders under DSM-5 criteria

Article Title: Randomized controlled trials of psychological treatments for eating disorders in the DSM-5 era: a systematic scoping review and evidence map

Article References: Randomized controlled trials of psychological treatments for eating disorders in the DSM-5 era: a systematic scoping review and evidence map. (n.d.). https://doi.org/10.1186/s40337-026-01797-2

Image Credits: AI Generated

DOI: 10.1186/s40337-026-01797-2

Keywords: eating disorders, psychotherapy, randomized controlled trials, scoping review, DSM-5, cognitive behavioral therapy, binge-eating disorder, anorexia nervosa, bulimia nervosa, ARFID, digital interventions, evidence map