Table 1 Main outcomes of studies on universal campus-wide interventions

Aseltine et al., 2004 [42]

Signs of Suicide (SOS) prevention program

RCT (wait-list control group with follow up at 3 months postintervention)

Reduce suicidal ideation

No significant reduction in suicidal ideation.

Small (d = 0.15)

Reduce suicide attempts

Significant reduction in suicide attempts.

Small (d = 0.26)^a

Change knowledge

Significant increase in knowledge.

Small (d = 0.38)^a

Change attitudes

Significant increase in adaptive attitudes toward suicide.

Small (d = 0.40)^a

Increase in help-seeking behaviour

No significant increase in help seeking in the form of treatment.

No significant increase in help seeking from a friend.

No significant increase in help seeking from an adult.

Small (d = 0.12)

Small (d = 0.04)

Small (d = 0.13)

Aseltine et al., 2007 [43]

Signs of Suicide (SOS) prevention program

RCT (wait-list control group with follow up at 3 months postintervention)

Reduce suicidal ideation

No significant reduction in suicidal ideation.

Small (d = 0.10)

Reduce suicide attempts

Significant reduction in suicide attempt.

Small (d = 0.26)

Change knowledge

Significant increase in knowledge about suicide.

Small (d = 0.32)

Change attitudes

Significant increase in adaptive attitudes toward suicide.

Small (d = 0.10)

Increase in help-seeking behaviour

No significant increase in help seeking in the form of treatment.

No significant increase in help seeking from a friend.

No significant increase in help seeking from an adult.

Small (d = 0.02)

Small (d = 0.02)

Small (d = 0.08)

Britton et al., 2014 [44]

Classroom-based, teacher implemented, mindfulness meditation intervention

RCT (active control condition with postintervention follow up only)

Reduce suicidal ideation

Reduce suicidal behaviour

Significant reduction in suicidal ideation and self-harm.

Large (d = 1.13)

Kalafat & Elias, 1994 [45]

Suicide awareness curriculum

Solomon four-groups design (physical education content control group with postintervention follow up only)

Change knowledge

Significant increase in suicide knowledge.

Large (d = 0.91)

Change attitudes

Significant change in positive attitudes towards suicide and helping others.

Small (d = 0.17)

Nasution et al., 2019 [46]

Combination of training for mental health nurses (TKN), CBT and a peer leadership (PL) program

Quasiexperimental pre-post test design (care as usual control group with postintervention only follow up)

Reduce suicidal ideation

Significant reduction in suicidal ideation.

Insufficient statistics

Randell et al., 2001 [47]

C-CARE - Counselors CARE

Experimental three-group design (care as usual control group with follow up at 4-weeks and 10-weeks)

Reduce suicide risk: unspecified

Significant reduction in suicide risks behaviours (thoughts, threats, and attempts) in intervention and control group.

Large (d = 0.90)

Randell et al., 2001 [47]

CAST - C-CARE plus a 12-session Coping and Support Training

Experimental three-group design (care as usual control with follow up at 4-weeks and 10-weeks)

Reduce suicide risk: unspecified

Significant reduction in suicide risks behaviours (thoughts, threats, and attempts) in intervention and control group.

Large (d = 0.90)

Rogers et al., 2018 [48]

Psychoeducation and Interpersonal exposure

RCT (control group browsed the National Diabetes Education website with a postintervention and 1-month follow up)

Reduce stigma

Significant reduction in stigma of suicide.

Small (d = 0.46)

Significant greater reduction in suicide-related stigma among those with prior exposure to suicide at post-intervention.

Small (d = 0.28)

Significant greater reduction in suicide-related stigma among those with prior exposure to suicide at one-month follow-up.

Small (d = 0.40)

Schilling et al., 2016 [49]

Signs of Suicide (SOS) prevention program

RCT (wait-list control group with a 12-weeks post-baseline follow up)

Reduce suicidal ideation

No significant reduction in suicidal ideation.

Small (d = 0.01)

Reduce suicide plan

Significant reduction in suicide plan.

Large (d = 1.05)

Reduce suicide attempts

Significant reduction in suicide attempt.

Large (d = 0.72)

Change knowledge

Significant increase in knowledge.

Small (d = 0.28)

Change attitudes

Significant change in adaptive attitudes about suicide.

Small (d = 0.05)

Wasserman et al., 2015 [50]

Question, Persuade, Refer (QPR)

Cluster-RCT (control group exposed to six educational posters displayed in their classrooms with a 3-month and 12-month follow up)

Reduce suicidal behaviour

No significant reduction in suicidal behaviour at 3-month follow up.

Small (d = −0.26)

No significant reduction in suicidal behaviour at 12-month follow-up.

Small (d = −0.20)

Wasserman et al., 2015 [50]

ProfScreen

Cluster-RCT (control group exposed to six educational posters displayed in their classrooms with a 3-month and 12-month follow up)

Reduce suicide attempts

No significant reduction in likelihood of suicide attempt at 3-month follow-up.

Small (d = − 0.14)

Significant reduction in likelihood of suicide attempt at 12-month follow-up.

Large (d = −0.44)

Wasserman et al., 2015 [50]

Youth Aware of Mental Health Programme (YAM)

Cluster-RCT (control group exposed to six educational posters displayed in their classrooms with a 3-month and 12-month follow up)

Reduce suicide attempts

No significant reduction in the likelihood of suicide attempts at 3-month follow-up.

Small (d = − 0.14)

No significant reduction in the likelihood of suicide attempts at 12-month follow-up.

Small (d = −0.44)

Wulandari et al., 2019 [51]

Peer leadership training (team formation and building, adolescent related projects, and team activities)

Quasi-experimental pretest–posttest design (no control group with postintervention follow up)

Reduce suicidal ideation

Significant reduction in suicidal ideation.

Insufficient statistics

Wyman et al., 2010 [52]

Source of Strengths prevention program

RCT (wait-list control group with postintervention and 1 year follow up)

Increase help-seeking behaviour

Significant increase in positive expectation that adults at school would help suicidal students.

Medium (d = 0.75)^a

Significant increase in norms for help-seeking from adults at school.

Medium (d = 0.62)^a

No significant increase in connecting distressed peers to adults.

Small (d = 0.21)^a