Background Anxiety disorders are common among primary-school aged children, but few affected children receive evidence-based treatment. Identifying and supporting children who experience anxiety problems through schools would address substantial treatment access barriers that families and school staff often face. We have worked with families and school staff to co-design procedures that incorporate screening, feedback for parents, and the offer of a brief intervention in primary schools. This study sets out to assess the feasibility of a subsequent school-based cluster randomised controlled trial to evaluate these procedures. Our objectives are to ensure our procedures for identifying and supporting children with anxiety difficulties through primary schools are acceptable and there are no negative impacts, to estimate recruitment and retention rates, and to identify any changes needed to study procedures or measures. Methods We will recruit six primary/junior schools in England (2 classes per school), and invite all children (aged 8–9) (n = 360) and their parent/carer and class teacher in participating classes to take part. Children, parents and class teachers will complete questionnaires at baseline and 12-week follow-up. Children who ‘screen positive’ on a 2-item parent-report child anxiety screen at baseline will be the target population (expected n = 43). Parents receive feedback on screening questionnaire responses, and where the child screens positive the family is offered support (OSI: Online Support and Intervention for child anxiety). OSI is a brief, parent-led online intervention, supported by short telephone sessions with a Children’s Wellbeing Practitioner. Participants’ experiences of study procedures will be assessed through qualitative interviews/discussion groups. Discussion Evidence-based procedures for identifying and supporting children with anxiety difficulties through primary schools would improve children’s access to timely, effective intervention for anxiety difficulties. Trial registration ISRCTN registry: ISRCTN30032471. Retrospectively registered on 18 May 2021.

BackgroundOver a quarter of people have an anxiety disorder at some point in their life, with many first experiencing difficulties during childhood or adolescence. Despite this, gaps still exist in the current evidence base of the multiple consequences of childhood anxiety problems and their costs.MethodsA systematic review of Medline, PsycINFO, EconLit and the National Health Service Economic Evaluation Database was conducted for longitudinal and economic studies reporting on the association between childhood anxiety problems and at least one individual‐, family‐ or societal‐level outcome or cost. All studies were synthesised narratively. For longitudinal studies, ‘effect direction’ was used as a common metric, with random effects meta‐analysis undertaken where possible.ResultsEighty‐three studies met inclusion criteria and were synthesised narratively. We identified 788 separate analyses from the longitudinal studies, which we grouped into 15 overarching outcome domains. Thirteen of the studies were incorporated into 13 meta‐analyses, which indicated that childhood anxiety disorders were associated with future anxiety, mood, behaviour and substance disorders. Narrative synthesis also suggested associations between anxiety problems and worse physical health, behaviour, self‐harm, eating, relationship, educational, health care, employment, and financial outcomes. ‘Effect direction’ was conflicting in some domains due to a sparse evidence base. Higher economic costs were identified for the child, their families, healthcare providers and wider society, although evidence was limited and only covered short follow‐up periods, up to a maximum of 2 years. Total annual societal costs per anxious child were up to £4040 (2021 GBP).ConclusionsChildhood anxiety problems are associated with impaired outcomes in numerous domains, and considerable economic costs, which highlight the need for cost‐effective interventions and policies to tackle them. More economic evidence is needed to inform models of the long‐term, economic‐related, consequences of childhood anxiety problems.