Depressive symptoms and neuroticism mediate the association between traumatic events and suicidality - A latent class mediation analysis of UK Biobank Database

Background Mental disorders that follow traumatic experience may increase risk of suicidality, but a comprehensive approach to understand how these mental disorders mediate the association between psychological traumatic experience and suicidality should be elucidated. In this study, we attempted to provide comprehensive evidence on how depressive symptoms and neuroticism can mediate the association between psychological traumatic experiences and suicidal behaviours including suicidal ideation, suicidal planning, and suicide attempts. Methods We analyzed 111,931 participants from UK Biobank who had completed mental health web-based questionnaire from 2016 to 2017. “Self-harm and suicidal behaviour and ideation (SSBI) score” was calculated by the response from suicidal behaviours and self-harm questionnaires. Conducting multivariate linear regression, depressive symptoms, anxiety symptoms, and neuroticism were selected as potential mediators. We constructed a latent class mediation model estimated direct effect of psychological traumatic events on suicidality and indirect effect of psychological traumatic events mediated by depressive symptoms and neuroticism. Results Psychological traumatic events were positively associated with suicidal behaviours. Depressive symptoms and neuroticism significantly mediated the effect of psychological traumatic events on suicidality. Anxiety symptoms did not mediate the association between psychological traumatic events and suicidality. Conclusion Psychological traumatic events, irrespective of life stage of occurrence, are associated with suicidality. The association between psychological traumatic events and suicidality can be partially explained by depressive symptoms and neuroticism of those who were exposed to psychological trauma.