Selective personality‐targeted prevention of suicidal ideation in young adolescents: post hoc analysis of data collected in a cluster randomised controlled trial

OBJECTIVE: To assess the efficacy of a selective, personality‐targeted intervention for reducing suicidal ideation in adolescents. DESIGN: Post hoc analysis of survey data collected in the Climate and Preventure (CAP) study, a cluster randomised controlled trial that compared strategies for reducing alcohol misuse by adolescents, 2012–2015. SETTING, PARTICIPANTS: Year 8 students at 16 New South Wales non‐government schools and one Victorian non‐government school. INTERVENTION: Preventure, a selective, personality‐targeted intervention designed to help adolescents with personality risk factors for alcohol misuse, comprising two 90‐minute sessions, one week apart. For our post hoc analysis, we combined data from the two CAP trial groups in which Preventure was offered (the Preventure and the Preventure/Climate Schools [a non‐selective prevention strategy] groups) as the intervention group; and data from the two groups in which Preventure was not offered (usual health education only [control] and Climate Schools groups) as the control group. MAIN OUTCOME MEASURE: Difference between post hoc control and intervention groups in the change in proportions of students reporting suicidal ideation during the preceding six months (single item of Brief Symptom Inventory depression subscale) over three years. RESULTS: A total of 1636 students (mean age at baseline, 13.3 years; standard deviation, 0.5 years) were included in our analysis, of whom 1087 (66%) completed the suicidal ideation item in the three‐year follow‐up assessment. The post hoc control group included 755 students (nine schools), the intervention group 881 students (eight schools). After adjusting for nesting of students in schools and sex, reporting of suicidal ideation by students who had received Preventure had declined over three years, compared with the control group (per year: adjusted odds ratio, 0.80; 95% CI, 0.66–0.97). CONCLUSION: Personality‐targeted selective prevention during early secondary school can have a lasting impact on suicidal ideation during adolescence. TRIAL REGISTRATION (CAP STUDY ONLY): Australian and New Zealand Clinical Trials Registry, ACTRN12612000026820 (prospective).