This editorial introduces the Journal’s 2026 Annual Research Review (ARR). Three themes emerged in this year’s ARR. The first revisits and expands our understanding of four longstanding mental health disorders – non-fatal self-harm, early conduct problems, eating, disorders and developmental language disorders. A second theme focuses on intervention development and efficacy by reviewing research on modifying school climates and behavioural treatments to address young children’s exposure to trauma. A final paper provides a systematic review of meta-analyses on the predictive validity of caregiver sensitivity. Cumulatively, this set of review papers provides important updates on a wide range of prevalent and meaningful disorders, expanding our understanding of aetiology, developmental course, and in many cases, success (or lack thereof) to assess and treat these conditions.