Explaining how childhood physical abuse and physical neglect influence adult depression: An analysis with multiple sequential mediators

Background: Substantial evidence indicates that experiencing physical abuse and neglect during childhood significantly elevates the likelihood of developing depression in adulthood. Nevertheless, there remains a dearth of understanding regarding the mechanisms underpinning this correlation. Objective: In this study, we aimed to examine the associations of childhood physical abuse and physical neglect with depression using follow-up data from UK Biobank and quantified the contribution of smoking, insomnia, and BMI in these associations. Participants and settings: This study included 144,704 participants (64,168 men and 80,536 women) from UK Biobank, most of whom were white (97 %). Methods: Physical abuse and physical neglect were measured using two items of Childhood Trauma Screener (CTS). Data on the incidence of depression were obtained from primary care, hospital inpatient records, self-reported medical conditions, and death registries. We used a sequential mediation analysis based on the "g-formula" approach to explore the individual and joint effects of potential mediators. Results: The depression incidence rate was 1.85 per 1000 person-years for men and 2.83 per 1000 person-years for women, respectively. Results of Cox proportional risk regression showed that physical abuse (HRs: 1.39-1.53, P < 0.001) and physical neglect (HRs: 1.43-1.60, P < 0.001) are associated with depression. Smoking, insomnia, and BMI together mediated 3 %-26 % of the associations. Conclusions: These findings contribute to our understanding of how physical abuse and physical neglect influence depression. Furthermore, a more effective reduction in the burden of depression can be achieved by managing modifiable mediators.