Determining the longitudinal associations between suicidal ideation and biopsychosocial factors in early- to mid-adolescence: a prospective cohort study

Objectives: To determine whether a biopsychosocial model of suicidality, specifically sleep, nutrition, physical exercise, mindfulness, social connectedness, lower socioeconomic status, and sex are uniquely associated with increased suicidal ideation, longitudinally over adolescence.Design: Longitudinal, prospective cohort study.Setting: A structured self-report questionnaire was collected as part of the Longitudinal Adolescent Brain Study at the University of the Sunshine Coast's Thompson Institute, (Queensland, Australia) from July 2018 - January 2024.Participants: 159 Australian adolescents (n=91 female; 68 male) aged 12 to 17 years.Outcome measures: Self-reported suicidal ideation was measured longitudinally. Data were also collected on self-reported lifestyle factors (sleep, nutrition, physical exercise, mindfulness, social connectedness), psychological distress, socioeconomic status, and sex. All measures were collected at 4-monthly intervals for each participant for up to 5 years (maximum of 15 time points).Results: Significant relationships were identified between increased suicidal ideation and poor sleep (odds ratio [OR] 2.6, 95% CI 1.4-4.6, p = .002), socioeconomic disadvantage (SES Quintile 1: OR 6.3 [95% CI, 1.8-21.8, p = .004; SES Quintile 2: OR 8.7, 95% CI 1.4-56.2, p = .022), psychological distress (OR 5.7, 95% CI 2.1-15.6, p = <.001) and eating habits (β -0.08, 95% CI -0.2--0.0).Conclusions: Poor sleep, socioeconomic disadvantage, psychological distress and eating habits were all found to be significantly associated with increased adolescent suicidal ideation over time. These biopsychosocial factors should be considered in targeted interventions and policies for reducing adolescent suicidality. Further research should employ multilevel modelling to examine factor interactions and rigorously evaluate interventions targeting lifestyle factors and socioeconomic inequalities through randomised controlled trials and quasi-experimental designs.