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.