摘要:Posttraumatic stress disorder (PTSD) has been a controversial diagnosis, with concerns including the sheer number of possible minimal diagnostic combinations (1,750), increasing to >10,000 theoretical possibilities in Diagnostic and Statistical Manual of Mental Disorders (5th ed.) proposals. This study examined whether the theoretical combinations postulated actually occur in a large sample of military personnel. The design of the study was a retrospective examination of PTSD checklists from 3,810 participants who, based on scores, endorsed symptoms consistent with probable PTSD. Combinations of PTSD Checklist–Civilian Version (PCL-C) symptom clusters were identified using data from active-duty military personnel who completed the 2005 and the 2008 Department of Defense (DoD) Health Related Behaviors Among Active Duty Military Personnel Survey. The study examined (a) occurrence of combinations, (b) unique minimum combinations, (c) most frequent combinations, and (d) replication of symptom combinations and clusters. The PCL-C scores showed 1,837 unique scoring combinations, 83.5% (1,533/1,837) of the observed unique scoring combinations occurred just once. The most frequently occurring combination (17/17 endorsed) accounted for 955 participants (25.1%), the second most frequent (16/17 endorsed) accounted for 75 participants (2.0%). PTSD most often presented as a unique constellation of symptom clusters, either capturing symptoms while allowing for considerable variability in its presentation, reflecting different severities of the disorder, or raising concerns about the classification itself, and any future classification that Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-V) might develop.