Abstract
INTRODUCTION: There is debate into the impact of universal, school-based interventions to improve emotional outcomes. Previous reviews have only focused on anxiety and depression symptoms, omitting broader internalising symptoms, nor include the proliferation of newer studies which have focused on mindfulness in schools. METHODS: We conducted a systematic review and meta-analysis, searching MEDLINE, Embase, PsycINFO, and Cochrane Central Register of Controlled trials for studies focusing on universal interventions to improve emotional outcomes for young people aged 8-18 until 15/12/2022. The primary focus were post-intervention self-report anxiety, depression and internalising outcomes. We prospectively registered the study with PROSPERO, number (CRD42020189845). Risk of bias was assessed using specially devised tools adopted from Cochrane. RESULTS: In total, 71 unique studies with a total sample of 63,041 young people met the inclusion criteria. This included 40 studies with 35,559 participants for anxiety outcomes, 50 studies with 49,418 participants for depression outcomes, and 15 studies with 21,473 participants for internalising outcomes. Pupils who received universal school-based interventions had significantly improved anxiety (d = -0.0858, CI = -0.15, -0.02, z = -2.46, p < .01) and depression (d = -0.109, CI = -0.19, -0.03, z = -2.60, p < 0.013), but not internalising outcomes. For anxiety disorders, intervention theory moderated the intervention effectiveness (Q = 24.93, p < 0.001), with CBT principles being significantly more effective than those that applied mindfulness or other/multiple theories. DISCUSSION: Evidence suggests that universal, school-based approaches for anxiety and depression produce small effect sizes for pupils. We conclude that used as a population health approach, these can have an impactful change on preventing anxiety and depression. However, intervention developers and researchers should critically consider which theories/approaches are being applied, particularly when trying to improve anxiety outcomes. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42020189845.