Previous research indicates a relationship between perceived fear for one's safety (i.e., threat appraisal) and posttraumatic stress disorder (PTSD). This prospective study examined relationships among deployment‐ and predeployment‐related variables, threat appraisal, and postdeployment PTSD symptom severity. Prior to Iraq deployment, 774 U.S. Army soldiers completed self‐report measures assessing previous life stressors, deployment history, current (predeployment) PTSD symptoms, deployment preparedness, and unit cohesion. Following deployment, participants completed self‐report measures assessing combat intensity, deployment threat appraisal, and current (postdeployment) PTSD symptoms. Structural equation modeling revealed that predeployment PTSD symptom severity, prior warzone deployment, unit cohesion, and preparedness were each independently associated with deployment threat appraisal, even after taking into account combat intensity. Deployment threat appraisal was associated with postdeployment PTSD severity. Results indicated that predeployment PTSD symptom severity, history of warzone deployment, and preparedness—risk factors previously thought to influence PTSD outcomes directly—were either partially or fully mediated by threat appraisal. The model explained 15% of the variance in deployment threat appraisal and 50% of the variance in postdeployment PTSD severity. Helping service members cope with exposure to extreme stress during deployment by modifying certain prewar risk factors may facilitate reduction of PTSD symptoms following deployment. 標題：服役前風險因素、戰區危險度評價和退役後PTSD症狀的關係 撮要：有研究指出自身安全的覺察恐懼(即危險度評價)和創傷後壓力症(PTSD)互相關連。本前瞻性研究檢視服役中和服役前的相關變量、危險度評價、和退役後PTSD症狀幅度。774名美國人到伊拉克服役前完成自我報告測試，評核：昔日生活壓力、服役史、現行(服役前)PTSD症狀、服役準備、和單位凝聚力。而退役後，軍人亦會填寫自我報告測試，評估：戰鬥劇烈程度、服役危險度評價和現行(退役後)PTSD症狀。結構方程式模型顯示：在撇除戰鬥劇烈程度後，服役前PTSD症狀幅度，以往戰區服役情況，單位凝聚力和服役準備都各自獨立地與服役危險度評價有關連。服役危險度評價亦與退役後PTSD幅度相關。結果指出服役前PTSD症狀幅度、戰區服役史和服役準備此等風險因素，曾被認為直接影響PTSD後果，都是局部或全部經由危險評價作中介。此模型能有效解釋服役危險度評價的15%方差，和服役後PTSD幅度的50%方差。透過調整某些戰前風險因素，以協助軍人面對極端服役壓力，可能服役後有效減少PTSD症狀。 标题：服役前风险因素、战区危险度评价和退役后PTSD症状的关系 撮要：有研究指出自身安全的觉察恐惧(即危险度评价)和创伤后压力症(PTSD)互相关连。本前瞻性研究检视服役中和服役前的相关变量、危险度评价、和退役后PTSD症状幅度。774名美国人到伊拉克服役前完成自我报告测试，评核：昔日生活压力、服役史、现行(服役前)PTSD症状、服役准备、和单位凝聚力。而退役后，军人亦会填写自我报告测试，评估：战斗剧烈程度、服役危险度评价和现行(退役后)PTSD症状。结构方程式模型显示：在撇除战斗剧烈程度后，服役前PTSD症状幅度，以往战区服役情况，单位凝聚力和服役准备都各自独立地与服役危险度评价有关连。服役危险度评价亦与退役后PTSD幅度相关。结果指出服役前PTSD症状幅度、战区服役史和服役准备此等风险因素，曾被认为直接影响PTSD后果，都是局部或全部经由危险评价作中介。此模型能有效解释服役危险度评价的15%方差，和服役后PTSD幅度的50%方差。透过调整某些战前风险因素，以协助军人面对极端服役压力，可能服役后有效减少PTSD症状。