Reducing nonfatal suicidal behaviour among university students: actuarial analysis of potential effects of treating common mental disorders

Campus-based suicide prevention is an important priority for universities. One approach could be to identify and treat common mental disorders, but it is unclear what potential reduction in suicide might be achieved by such an approach. Our aim was to quantify this potential effect on prevalence of nonfatal suicidal behaviour among first-year students. Data were collected from students at two South African universities ( N = 633) via an online survey. We assessed prevalence of nonfatal suicidal behaviour and six common mental disorders and used logistic regression models to identify all main and interaction associations of sociodemographic variables and common mental disorders as predictors of nonfatal suicidal behaviour. Population attributable risk analysis was used to quantify the potential reduction in nonfatal suicidal behaviour achieved by effectively treating common mental disorders, based on the simplifying assumption that the logistic regression coefficients of the common mental disorders represented causal effects on nonfatal suicidal behaviour. Twelve-month prevalence of suicidal ideation, plan, and attempt were 40.9%, 22.3%, and 3.9%, respectively. Increased risk was associated with identifying as Black, female and reporting an atypical sexual orientation. Of the six common mental disorders, major depressive disorder and generalised anxiety disorder were associated with all dimensions of nonfatal suicidal behaviour, bipolar spectrum disorder with increased risk of ideation and plan, attention-deficit/hyperactivity disorder with ideation, and alcohol use disorder with suicide plan. Population attributable risk analysis suggests that treating common mental disorders could yield absolute reductions in suicide ideation, plan, and attempt of 17.0%, 55.0% and 73.8%, respectively. Pragmatic trials are needed to evaluate the effects on nonfatal suicidal behaviour of identifying and treating students with a prior history of common mental disorder early in their university careers.