Intelligence quotient, combat experiences, psychosocial functioning, and depressive symptoms’ roles in PTSD symptom severity and treatment completion

Pre-, peri-, and post-deployment factors, including demographic factor, psychological traits, and previous trauma experience, have been hypothesized to influence severity of combat-related posttraumatic stress disorder (PTSD) and whether an individual completes a treatment trial. Here we report on the roles of these factors on pretreatment PTSD symptom severity and how these factors affected treatment drop-out in 103 participants enrolled in a previously conducted treatment trial for PTSD for these individuals. We found that comorbid depression, IQ, breadth of combat experiences, and psychosocial functioning play significant roles in accounting for PTSD severity, with those five variables accounting for ∼51% of the variance, with depressive symptoms (∼38% of the variance in CAPS total score), extent of trauma exposure (∼5%), IQ (∼3%), the index trauma being related to witnessing a threat (∼3%), and psychosocial functioning (∼2%) contributing significantly. The same factors were investigated to assess their influence on completion of treatment protocols, where higher IQs and less diversity of trauma exposures were associated with a higher completion rate. Thus, the factors contributing to PTSD symptoms and treatment completion are diverse, encompass pre-, peri-, and post-trauma conditions, and span the breadth of neurobiological, combat, and psychosocial factors. ClinicalTrials.gov identifier: NCT01391832.