Main comparisons of student outcomes at postintervention follow-up
| Secondary outcomes | SBMT arm (I) | TAU arm (C) | Unadjusted | Adjusted mean difference (I-C)/OR ratio (I/C)* | ICC† | ||||
| N | Mean (SD)/N (%) | N | Mean (SD)/N(%) | Mean diff. (I-C)/OR (I/C)* | Estimate | 95% CI | P value | ||
| Depression (CES-D) | 3768 | 16.9 (11.8) | 3793 | 16.4 (11.6) | 0.4 | 0.2 | −0.4 to 0.8 | 0.51 | 0.016 |
| Social-emotional and behavioural functioning (SDQ)—self report | |||||||||
| Total difficulties | 3752 | 13.4 (6.9) | 3790 | 13.1 (6.8) | 0.3 | 0.2 | −0.1 to 0.6 | 0.15 | 0.018 |
| Well-being (WEMWBS) | 3775 | 47.8 (9.6) | 3797 | 48.1 (9.3) | −0.2 | −0.2 | −0.7 to 0.3 | 0.44 | 0.015 |
| Social-emotional and behavioural functioning (SDQ)—self report | |||||||||
| Emotional symptoms | 3752 | 4.0 (2.8) | 3790 | 3.8 (2.7) | 0.2 | 0.1 | −0.04 to 0.2 | 0.15 | 0.020 |
| Conduct problems | 3752 | 2.6 (2.0) | 3790 | 2.6 (2.0) | 0.007 | −0.009 | −0.1 to 0.1 | 0.86 | 0.015 |
| Hyperactivity/inattention | 3752 | 4.7 (2.6) | 3790 | 4.5 (2.6) | 0.1 | 0.2 | 0.04 to 0.3 | 0.01 | 0.015 |
| Peer relationship problems | 3752 | 2.2 (1.9) | 3790 | 2.2 (1.9) | −0.001 | 0·0002 | −0.1 to 0.1 | 1.00 | 0.012 |
| Prosocial behaviour | 3752 | 7.5 (2.0) | 3790 | 7.4 (1.9) | 0.008 | −0.03 | −0.1 to 0.1 | 0.54 | 0.021 |
| Executive processing (BRIEF-2)—self-report | 3115 | 85.7 (22.2) | 3426 | 84.9 (21.9) | 0.4 | 0.1 | −1.5 to 1.7 | 0.90 | 0.014 |
| Executive processing (BRIEF-2)—teacher-report | 3083 | 80.2 (24.6) | 2451 | 80.0 (24.5) | −0.3 | 0.2 | −2.7 to 3.0 | 0.91 | 0.066 |
| Drug use—self-report | 3410 | 458 (13.4) | 3621 | 524 (14.5) | 1.0 | 0.9 | 0.8 to 1.1 | 0.56 | 0.015 |
| Alcohol use—self-report | 3428 | 1556 (45.4) | 3630 | 1752 (48.3) | 0.9 | 1.0 | 0.8 to 1.2 | 0.67 | 0.075 |
| Anxiety (RCADS)—self-report | |||||||||
| Total score | 3487 | 31.3 (21.6) | 3688 | 29.1 (20.8) | 1.6 | 1.3 | −0.2 to 2.7 | 0.08 | 0.027 |
| Social phobia | 3492 | 10.9 (6.9) | 3694 | 10.4 (6.6) | 0.3 | 0.2 | −0.2 to 0.6 | 0.40 | 0.041 |
| Panic disorder | 3487 | 6.5 (6.1) | 3689 | 5.8 (5.9) | 0.5 | 0.4 | 0.03 to 0.9 | 0.04 | 0.019 |
| Separation anxiety | 3491 | 3.4 (3.6) | 3693 | 3.1 (3.5) | 0.2 | 0.2 | −0.05 to 0.4 | 0.12 | 0.017 |
| Generalised anxiety | 3499 | 6.2 (4.5) | 3697 | 5.8 (4.3) | 0.3 | 0.2 | −0.1 to 0.5 | 0.18 | 0.027 |
| Obsessive-compulsive | 3496 | 4.4 (3.8) | 3695 | 4.1 (3.7) | 0.3 | 0.3 | 0.01 to 0.5 | 0.04 | 0.016 |
| Social-emotional and behavioural functioning (SDQ)—teacher-report | |||||||||
| Total difficulties | 3071 | 5.9 (6.0) | 2451 | 5.6 (5.8) | 0.3 | 0.3 | −0.3 to 1.0 | 0.32 | 0.051 |
| Emotional symptoms | 3071 | 1.2 (1.9) | 2451 | 1.0 (1.9) | 0.1 | 0.2 | −0.1 to 0.4 | 0.14 | 0.044 |
| Conduct problems | 3071 | 0.9 (1.7) | 2451 | 0.8 (1.5) | 0.1 | 0.1 | −0.1 to 0.2 | 0.33 | 0.024 |
| Hyperactivity/inattention | 3071 | 2.5 (2.7) | 2451 | 2.5 (2.7) | 0.003 | 0.03 | −0.2 to 0.3 | 0.82 | 0.044 |
| Peer relationship problems | 3071 | 1.3 (1.7) | 2451 | 1.3 (1.7) | 0.05 | 0.1 | −0.1 to 0.3 | 0.48 | 0.035 |
| Prosocial behaviour | 3071 | 7.2 (2.6) | 2451 | 7.2 (2.6) | −0.004 | −0.05 | −0.4 to 0.3 | 0.77 | 0.049 |
| Self-harm—self-report | 3389 | 365 (10.8) | 3431 | 361 (10.5) | 1.0 | 1.0 | 0.8 to 1.2 | 0.94 | 0.015 |
| Suicide ideation—self-report | 3251 | 745 (22.9) | 3246 | 718 (22.1) | 1.0 | 1.0 | 0.9 to 1.2 | 0.70 | 0.015 |
| Mindfulness skills (CAMM)—self-report | 3703 | 26.0 (8.3) | 3769 | 26.7 (8.3) | −0.7 | −0.6 | −1.2 to −0.01 | 0.04 | 0.021 |
| School ecology/climate (SCCS) | |||||||||
| School leadership and student involvement | 3606 | 3.2 (0.8) | 3749 | 3.2 (0.9) | 0.006 | 0.009 | −0.1 to 0.1 | 0.88 | 0.070 |
| Respectful climate | 3600 | 3.2 (0.8) | 3746 | 3.3 (0.8) | −0.1 | −0.04 | −0.1 to 0.04 | 0.32 | 0.047 |
| Peer climate | 3598 | 3.0 (0.8) | 3745 | 3.0 (0.8) | −0.02 | −0.04 | −0.1 to 0.05 | 0.41 | 0.061 |
| Caring adults | 3593 | 3.1 (0.9) | 3744 | 3.2 (0.9) | −0.04 | −0.02 | −0.1 to 0.1 | 0.53 | 0.036 |
*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; I/C, intervention arm / control arm ; I-C, intervention arm - control arm; RCADS, Revised Child Anxiety and Depression Scale; SBMT, school-based mindfulness training; SCCS, School Climate and Connectedness Survey; SDQ, Strengths and Difficulties Questionnaire; TAU, teaching as usual; WEMWBS, Warwick-Edinburgh Mental Well-Being Scale.