Minimising young children’s anxiety through schools (MY-CATS): protocol for a cluster randomised controlled trial to evaluate the effectiveness and cost-effectiveness of an online parent-led intervention compared with usual school practice for young children identified as at risk for anxiety disorders

Background Identifying and supporting young children who are at risk of developing anxiety disorders would benefit children, families, and wider society. Elevated anxiety symptoms, inhibited temperament, and high parental anxiety are established risk factors for later anxiety disorders, but it remains unclear who is most likely to benefit from prevention and early intervention programmes. Delivering an online intervention through schools to parents of young children who have one or more of these risks could maximise reach. The primary aim of this trial is to evaluate the effectiveness and cost-effectiveness of delivering an online parent-led intervention, compared with usual school provision only, for children (aged 4–7) identified as at risk for anxiety disorders on the basis of at least one risk factor. We also aim to identify the characteristics of children who do and do not benefit from intervention and mechanisms of change from the intervention. Methods The design will be a parallel group, superiority cluster randomised controlled trial, with schools (clusters) randomised to intervention or usual school practice arms in a 1:1 ratio stratified according to level of deprivation within the school. The study will recruit and randomise at least 60 primary/infant schools in England, and on the basis of recruiting 60 schools, we will recruit 1080 trial participants (540 per arm). Parents of all children (aged 4–7) in sampled Reception, Year 1, and Year 2 classes will be invited to complete screening questionnaires. Children who screen positive on the basis of anxiety symptoms, and/or behavioural inhibition, and/or parent anxiety symptoms will be eligible for the trial. Parents/carers of children in schools allocated to the intervention arm will be offered a brief online intervention; schools in both arms will continue to provide any usual support for children and parents throughout the trial. Assessments will be completed at screening, baseline (before randomisation), 6 weeks, 12 weeks, and 12 months post-randomisation. The primary outcome will be the absence/presence of an anxiety disorder diagnosis at 12 months. Discussion The trial will determine if delivering an online intervention for parents of young children at risk of anxiety disorders identified through screening in schools is effective and cost-effective. Trial registration ISRCTN 82398107. Prospectively registered on Jan. 14, 2021