Brief Educational Workshops in Secondary Schools Trial (BESST): a cluster randomised controlled trial. Secondary analysis in those with elevated symptoms of depression

Background Depression and anxiety are increasingly prevalent in adolescents. The Brief Educational Workshops in Secondary Schools Trial investigated the effectiveness of a brief self-referral stress workshop programme for sixth-form students aged 16–18 years old.Objective This study conducted a secondary analysis on the outcomes of participants with elevated depressive symptoms at baseline.Methods This is an England-wide, multicentre, cluster randomised controlled trial to evaluate the clinical effectiveness and cost-effectiveness of a brief cognitive–behavioural therapy workshop (DISCOVER) compared with treatment-as-usual (TAU) (1:1). The primary outcome was depression symptoms (Mood and Feelings Questionnaire (MFQ)) at 6-month follow-up, using the intention-to-treat (ITT) population and analysed with a multilevel linear regression estimating a between-group adjusted mean difference (aMD). Cost-effectiveness, taking a National Health Service (NHS) and personal social services perspective, was explored using quality-adjusted life years (QALYs).Findings Between 4 October 2021 and 10 November 2022, 900 adolescents at 57 schools were enrolled. 314 students were identified as having elevated symptoms of depression at baseline (>27 on MFQ). In this prespecified subgroup, the DISCOVER arm included 142 participants and TAU included 172. ITT analysis included 298 participants. Primary analysis at 6 months found aMD to be −3.88 (95% CI −6.48, –1.29; Cohen’s d=−0.52; p=0.003), with a similar reduction at 3 months (aMD=−4.00; 95% CI −6.58, –1.42; Cohen’s d=0.53; p=0.002), indicating a moderate, clinically meaningful effect in the DISCOVER arm. We found an incremental cost-effectiveness ratio of £5255 per QALY, with a probability of DISCOVER being cost-effective at between 89% and 95% compared with TAU.Conclusions and clinical implications DISCOVER is clinically effective and cost-effective in those with elevated depressive symptoms. This intervention could be used as an early school-based intervention by the NHS.Trial registration number ISRCTN90912799.