Self-Reported Traumatic Brain Injury and Its Biopsychosocial Risk Factors in Siblings of Individuals with Neurodevelopmental Conditions.

Siblings of individuals with neurodevelopmental conditions (NDCs) are situated within a complex system of risk and resilience factors for poor outcomes, many of which overlap with the risk of traumatic brain injury (TBI) and correlate with poorer recovery trajectories. This study used Bayesian analyses to characterize and compare TBI and biopsychosocial risk factors among 632 siblings (207 NDC, 425 controls; mean age 20.54 years, range 10-30, 78.48% female). NDC siblings had a higher self-reported lifetime history of TBI compared to controls (14.98% versus 6.35%), with most reporting more than one TBI, and at an earlier age. TBI history was associated with psychiatric diagnoses and subclinical NDC features. Family and structural factors related to TBI included poorer parent-child relationship, NDC diagnoses of autism or fetal alcohol spectrum disorder, minority ethnicity, and lower income. Findings have implications for health literacy, TBI education and screening, and implementation of family support.