Not only has accidental injury been shown to account for a significant health burden on all populations, regardless of age, sex and geographic region, but patients with accidental injury frequently present with the psychiatric condition of posttraumatic stress disorder (PTSD). Prevention of accident-related PTSD thus represents a potentially important goal. Physicians in the field of psychosomatic medicine and critical care medicine have the opportunity to see injured patients in the immediate aftermath of an accident. This article first briefly reviews the prevalence and associated factors of accident-related PTSD, then focuses on a conceptual model of fear memory and proposes a new, rationally hypothesized translational preventive intervention for PTSD through promoting hippocampal neurogenesis by omega-3 fatty acid supplementation. The results of an open-label pilot trial of injured patients admitted to the intensive care unit suggest that omega-3 fatty acid supplementation immediately after accidental injury can reduce subsequent PTSD symptoms.