Effectiveness without safety: a response to Duggan, Hardy, and Waller (2026).

Abstract

This commentary responds to Duggan, Hardy, and Waller's systematic review and meta-analysis of cognitive-behavioural therapy (CBT) for outpatients with anorexia nervosa (AN). Although the review synthesises evidence of clinical benefit, it does not define, extract, or discuss iatrogenic harm or reasons for dropout. This omission limits what can be inferred from the review's conclusions. Effectiveness and safety are distinct evidentiary domains: improvement in weight or eating disorder (ED) symptoms does not demonstrate absence of iatrogenic harm, especially when clinical trials have not systematically defined, monitored, or reported treatment-related risks. Evidence-based care requires not only evidence of effectiveness, but also evidence about safety. This commentary argues that evidence syntheses may produce an unduly favourable account of treatment impact when they quantify and emphasise benefit without equivalent attention to iatrogenesis, weakening informed consent and obscuring patient-reported experiences that may not be captured by symptom or weight outcomes alone. The paper considers methodological, clinical, ethical, epistemic, and intersectional implications of this asymmetry. It recommends that future ED clinical trials and systematic reviews evaluate benefit and harm together, undertake balanced assessments of benefits versus risks, use clearer harm definitions and patient-reported measures, report reasons for dropout, assess longer-term outcomes, and involve lived experience contributors substantively in study design, interpretation, and translation.