Main comparisons of student outcomes at 1 year follow-up
| Outcome | Intervention arm (I) | Control arm (C) | Unadjusted | Adjusted mean difference (I-C)/OR (I/C)* | ICC† | ||||
| N | Mean (SD)/N (%) | N | Mean (SD)/N (%) | Mean diff. (I-C)/OR (I/C)* | Estimate | 95% CI | P value | ||
| Co-primary outcomes | |||||||||
| Depression (CES-D) | 3672 | 17.1 (11.9) | 3566 | 16.6 (11.9) | 0.4 | 0.1 | −0.6 to 0.7 | 0.86 | 0.018 |
| Social-emotional and behavioural functioning (SDQ)—self report | |||||||||
| Total difficulties | 3664 | 13.2 (6.8) | 3561 | 12.9 (6.8) | 0.2 | 0.2 | −0.2 to 0.5 | 0.33 | 0.019 |
| Well-being (WEMWBS) | 3678 | 47.6 (9.8) | 3566 | 47.6 (9.8) | 0.1 | 0.2 | −0.3 to 0.7 | 0.50 | 0.014 |
| Secondary outcomes | |||||||||
| Social-emotional and behavioural functioning (SDQ)—self report | |||||||||
| Emotional symptoms | 3664 | 4.0 (2.7) | 3562 | 3.8 (2.7) | 0.1 | 0.1 | −0.1 to 0.2 | 0.25 | 0.019 |
| Conduct problems | 3664 | 2.4 (2.0) | 3562 | 2.5 (2.0) | −0.04 | −0.1 | −0.2 to 0.1 | 0.30 | 0.014 |
| Hyperactivity/inattention | 3664 | 4.6 (2.6) | 3562 | 4.5 (2.5) | 0.2 | 0.2 | 0.04 to 0.3 | 0.01 | 0.015 |
| Peer relationship problems | 3664 | 2.2 (1.9) | 3561 | 2.2 (1.9) | −0.01 | −0.01 | −0.1 to 0.1 | 0.78 | 0.016 |
| Prosocial behaviour | 3664 | 7.4 (2.0) | 3562 | 7.4 (2.0) | 0.03 | −0.01 | −0.1 to 0.1 | 0.81 | 0.025 |
| Executive processing (BRIEF-2)—self-report | 3288 | 84.3 (22.7) | 3329 | 83.6 (22.4) | 0.5 | 0.2 | −1.4 to 1.7 | 0.84 | 0.019 |
| Executive processing (BRIEF-2)—teacher report | 2489 | 77.8 (22.8) | 1990 | 78.7 (24.3) | −0.3 | 0.02 | −2.8 to 2.9 | 0.99 | 0.063 |
| Drug use—self-report | 3401 | 587 (17.3) | 3429 | 635 (18.5) | 0.9 | 0.9 | 0.8 to 1.1 | 0.38 | 0.016 |
| Alcohol use—self-report | 3436 | 1703 (49.6) | 3451 | 1729 (50.1) | 1.0 | 1.0 | 0.8 to 1.3 | 0.77 | 0.078 |
| Anxiety (RCADS)—self-report | |||||||||
| Total score | 3504 | 30.0 (21.5) | 3483 | 28.8 (21.6) | 1.0 | 0.4 | −1.0 to 1.9 | 0.56 | 0.026 |
| Social phobia | 3510 | 10.6 (6.9) | 3488 | 10.3 (6.8) | 0.2 | −0.01 | −0.4 to 0.4 | 0.96 | 0.033 |
| Panic disorder | 3504 | 6.2 (6.1) | 3485 | 5.8 (6.1) | 0.4 | 0.2 | −0.2 to 0.6 | 0.30 | 0.022 |
| Separation anxiety | 3508 | 3.2 (3.5) | 3488 | 3.1 (3.6) | 0.2 | 0.1 | −0.1 to 0.3 | 0.45 | 0.016 |
| Generalised anxiety | 3512 | 5.9 (4.4) | 3490 | 5.7 (4.4) | 0.1 | 0.03 | −0.3 to 0.3 | 0.86 | 0.025 |
| Obsessive-compulsive | 3512 | 4.1 (3.7) | 3489 | 3.9 (3.8) | 0.2 | 0.1 | −0.1 to 0.4 | 0.39 | 0.017 |
| Social-emotional and behavioural functioning (SDQ)—teacher-report | |||||||||
| Total difficulties | 2496 | 5.3 (5.7) | 1981 | 5.1 (5.8) | 0.5 | 0.6 | −0.2 to 1.3 | 0.14 | 0.065 |
| Emotional symptoms | 2496 | 1.1 (1.9) | 1981 | 1.0 (1.8) | 0.3 | 0.3 | 0.1 to 0.5 | 0.01 | 0.053 |
| Conduct problems | 2496 | 0.7 (1.5) | 1981 | 0.8 (1.5) | 0.05 | 0.1 | −0.1 to 0.2 | 0.48 | 0.035 |
| Hyperactivity/inattention | 2496 | 2.2 (2.6) | 1981 | 2.2 (2.6) | 0.1 | 0.1 | −0.2 to 0.4 | 0.59 | 0.049 |
| Peer relationship problems | 2496 | 1.2 (1.7) | 1981 | 1.2 (1.7) | 0.1 | 0.1 | −0.1 to 0.3 | 0.31 | 0.046 |
| Prosocial behaviour | 2496 | 7.6 (2.5) | 1981 | 7.5 (2.6) | 0.1 | 0.1 | −0.3 to 0.4 | 0.76 | 0.086 |
| Self-harm—self-report | 3364 | 389 (11.6) | 3234 | 385 (11.9) | 1.0 | 0.9 | 0.8 to 1.1 | 0.53 | 0.012 |
| Suicide ideation—self-report | 3224 | 779 (24.2) | 3098 | 709 (22.9) | 1.1 | 1.1 | 0.9 to 1.2 | 0.45 | 0.013 |
| Mindfulness skills (CAMM)—self-report | 3625 | 26.4 (8.5) | 3546 | 26.7 (8.7) | −0.3 | −0.1 | −0.6 to 0.5 | 0.78 | 0.019 |
| School ecology/climate (SCCS) | |||||||||
| School leadership and student involvement | 3587 | 3.1 (0.9) | 3530 | 3.1 (0.9) | −0.01 | −0.01 | −0.1 to 0.1 | 0.85 | 0.072 |
| Respectful climate | 3582 | 3.2 (0.8) | 3527 | 3.2 (0.8) | −0.01 | −0.01 | −0.1 to 0.1 | 0.89 | 0.038 |
| Peer climate | 3581 | 3.0 (0.7) | 3523 | 3.0 (0.7) | −0.004 | −0.01 | −0.1 to 0.1 | 0.74 | 0.060 |
| Caring adults | 3576 | 3.1 (0.9) | 3518 | 3.2 (0.9) | −0.04 | −0.03 | −0.1 to 0.04 | 0.48 | 0.031 |
*Mean difference reported for quantitative outcomes and OR reported for binary outcomes.
†Intracluster (intraschool) correlation coefficients (ICCs) from crude (unadjusted) analyses.
BRIEF-2, Behaviour Rating Inventory of Executive Function, Second Edition; CAMM, Child and Adolescent Mindfulness Measure; CES-D, Center for Epidemiologic Studies for Depression Scale; RCADS, Revised Child Anxiety and Depression Scale; SCCS, School Climate and Connectedness Survey; SDQ, Strengths and Difficulties Questionnaire; WEMWBS, Warwick-Edinburgh Mental Well-Being Scale.