Depression is a risk factor for traumatic brain injury: Evidence from the National Health and Nutrition Examination...

Previous studies have suggested an increased risk of post-traumatic depression in patients with traumatic brain injury (TBI). However, the pre-injury depression status of some included TBI patients remains unclear. This study aimed to investigate whether pre-existing depression increases the risk of TBI occurrence, thereby reassessing the causal relationship between depression and TBI.

A cross-sectional analysis was conducted using the National Health and Nutrition Examination Survey database for the periods 2011-2012 and 2013-2014. Multivariate-adjusted logistic regression was employed to evaluate the association between depression and TBI. Additionally, Mendelian randomization analysis was performed to examine potential causality.

Among 5773 eligible the National Health and Nutrition Examination Survey participants, a subset of TBI patients exhibited pre-injury depression. After adjusting for covariates, multivariate logistic regression revealed positive correlations between TBI risk and depression severity: moderate (log^OR = 0.67, 95% confidence interval (CI): 0.18-1.20; p = 0.015), moderate-to-severe (log^OR = 1.10, 95% CI: 0.62-1.20; p = 0.001), and severe depression (log^OR = 1.2, 95% CI: 0.32-2.10; p = 0.015). Mendelian randomization analysis further supported a causal link, with inverse-variance weighted estimates indicating that depression was associated with higher TBI incidence (odds ratio = 1.02, 95% CI: 1.00-1.03; p = 0.006). Sensitivity analyses confirmed the robustness of these findings.

The pre-existing depressive state in patients with TBI is a risk factor contributing to the occurrence of TBI. Preventive measures against TBI should be strengthened in depressive patients. Additionally, the impact of the pre-injury depression on the statistical analysis of neuropsychiatric complications following TBI warrants careful consideration.