Please use this link to access publication Abstract Introduction Traumatic brain injury (TBI) is a significant source of morbidity and mortality in the United States. Recent shifts in state legislation have increased the use of recreational and medical marijuana. While cannabinoids and tetrahydrocannabinol (THC) have known anti-inflammatory effects, the impact of preinjury THC use on clinical outcomes in the setting of severe TBI is unknown. We hypothesized that preinjury THC use in trauma patients suffering TBI would be associated with decreased thromboembolic events and adverse outcomes. Methods The American College of Surgeons Trauma Quality Improvement Program was used to identify patients aged ≥18 y with TBI and severe injury (Injury Severity Score ≥ 16) in...