Can exercise reduce the risk of suicidal ideation and behaviors in youth at school? A 12-month cluster randomized control trial.

Our aim was to investigate the effect of an aerobic exercise intervention on risk of suicidal ideation, behaviors and nonsuicidal self-injury among adolescents. This analysis included secondary outcomes of a randomized controlled trial investigating a 12-month aerobic exercise intervention. The intervention consisted of six months of supervised exercise delivered in a school setting, followed by six months of unsupervised exercise. There were three-four sessions of supervised moderate-intensity activities (60-80 % maximum heart rate) lasting 30 min each, with an additional of 10 min of warm-up and cool-down over the initial period. Different clusters of students were randomized into either exercise or a psychoeducation control group. Risk of suicidal ideation and nonsuicidal self-injury were assessed using the Inventory of Statements About Self-Injury, and suicidal behavior was assessed using the Columbia-Suicide Severity Rating Scale. The outcomes were analyzed using intention to treat analyses. Trial registration (ClinicalTrials.gov register, NCT04816617). The final sample was composed of 628 adolescents (13.0 ± 0.4 years, 43.3 % girls). In the adjusted models, there was no intervention effect on nonsuicidal self-injury for the whole sample or according to baseline subclinical levels of depressive symptoms. The exercise group presented a 49 % lower incidence of nonsuicidal self-injury incidence in participants with low baseline levels of physical activity (IRR: 0.49; 95 %CI: 0.25-0.97). There was no effect of the intervention on risk of suicidal ideation and suicidal behavior. A 12-month aerobic exercise intervention was associated with lower incidence of nonsuicidal self-injury in participants with low baseline levels of physical activity. The exercise intervention had no effect on the risk suicidal ideation and suicidal behavior.